Targeted Therapy: A Complete Patient and Family Guide

At a glance: Targeted therapy uses medicines designed to interfere with specific proteins, genes, receptors, enzymes, blood vessels, or cellular pathways that help cancer grow, survive, repair itself, or spread. Many targeted therapies are selected using biomarker testing.

Important: “Targeted” does not mean harmless, side-effect-free, or guaranteed to work. The same biological target may be important in one cancer but not another. Treatment must be matched to the cancer type, biomarker result, stage, previous therapy, organ function, and approved clinical setting.

Medication-safety reminder: Never start, stop, skip, double, crush, split, dissolve, or change the timing of an oral targeted medicine unless the oncology team or oncology pharmacist provides specific instructions. Contact the team about missed doses, vomiting after a dose, planned surgery, new prescriptions, nonprescription medicines, supplements, or major side effects.

Report symptoms early: Some targeted therapies can affect the heart, lungs, liver, kidneys, eyes, blood vessels, blood pressure, blood counts, skin, bowel, or wound healing. Follow the drug-specific emergency instructions supplied by the oncology team.

Quick Jump: Targeted Therapy Topics

• What Is Targeted Therapy?
• Cancer Growth and Molecular Targets
• Goals of Targeted Therapy
• Who May Benefit?
• When It May Not Be Recommended
• Precision and Personalized Medicine
• Biomarker Testing
• Tissue, Blood and Testing Methods
• Understanding Test Results
• Tumor Testing vs. Inherited Testing
• Major Types of Targeted Therapy
• Small-Molecule Inhibitors
• Monoclonal Antibodies
• Antibody-Drug Conjugates
• Bispecific Antibodies
• Angiogenesis Inhibitors
• Major Molecular Pathways
• Examples of Targeted Treatment
• Tumor-Agnostic Therapy
• How a Treatment Plan Is Selected
• How Treatment Is Given
• Schedules and Treatment Duration
• Preparing for Treatment
• Oral Targeted Therapy Safety
• Food, Drug and Supplement Interactions
• What Happens on Treatment Day?
• Laboratory and Clinical Monitoring
• How Doctors Know It Is Working
• Treatment Resistance
• Common Side Effects
• Side Effects by Drug Class
• Skin, Nail and Hand-Foot Effects
• Diarrhea and Digestive Effects
• Blood Pressure and Blood Vessels
• Heart and Rhythm Effects
• Lung Inflammation
• Liver and Kidney Effects
• Eye and Vision Effects
• Blood Counts and Infection
• Infusion and Allergic Reactions
• Surgery and Wound Healing
• Urgent Warning Signs
• Pregnancy, Fertility and Sexual Health
• Combination Treatment
• Long-Term Monitoring
• Nutrition and Physical Activity
• Supportive and Integrative Care
• Work, Travel and Daily Life
• Questions to Ask the Care Team
• Targeted Therapy Myths and Facts
• Clinical Trials and New Directions
• Costs and Financial Planning
• Treatment Checklist
• Trusted Resources

Targeted therapy is cancer treatment designed to interfere with particular molecular features that cancer cells use to grow, divide, survive, repair damage, form blood vessels, evade normal cell-death signals, or spread.

A treatment target may be:

• A mutated or abnormally activated protein
• A receptor on the cancer-cell surface
• An enzyme inside the cancer cell
• A gene fusion or rearrangement
• An amplified gene or overproduced protein
• A DNA-repair weakness
• A pathway controlling cell division
• A protein supporting cancer-cell survival
• A signal that promotes new blood-vessel growth
• An antigen used to deliver a drug directly to a cancer cell

Many targeted therapies are part of precision medicine because treatment is selected using information about the patient’s cancer rather than only the organ where it began.

National Cancer Institute: Targeted Therapy for Cancer

Targeted therapy versus chemotherapy: Traditional chemotherapy broadly attacks rapidly dividing cells. Targeted therapy is designed around a particular cancer feature or pathway. However, targeted medicines can still affect healthy cells that use the same pathway and can cause serious side effects.

Normal cells use tightly controlled signaling systems to decide when to grow, divide, repair damage, specialize, or die. Cancer cells may acquire molecular changes that disrupt these controls.

Cancer-promoting changes may cause a cell to:

• Send a constant growth signal
• Ignore signals telling it to stop dividing
• Repair DNA damage incorrectly
• Avoid programmed cell death
• Create new blood vessels
• Invade neighboring tissue
• Survive in another organ
• Evade immune destruction

Some cancers depend strongly on one dominant abnormal signal. This dependence is sometimes called an oncogenic driver. Blocking that driver can produce a major response.

Other cancers rely on several overlapping pathways. Blocking one may slow the cancer temporarily while another pathway takes over. This biological complexity helps explain why targeted treatments may work dramatically, partially, temporarily, or not at all.

The presence of a molecular change does not automatically prove that it is driving the cancer or that a particular medicine will help.

1. Curative Treatment

For selected cancers, targeted therapy may be part of a treatment plan intended to eliminate the cancer and produce a lasting remission. It may be used alone or with chemotherapy, surgery, radiation, hormone therapy, immunotherapy, or stem-cell transplantation.

2. Neoadjuvant Targeted Therapy

Treatment may be given before surgery to shrink a tumor, improve the likelihood of complete removal, increase organ preservation, or provide information about treatment response.

3. Adjuvant Targeted Therapy

Treatment may be given after surgery to reduce recurrence risk when the cancer has a target associated with benefit from postoperative therapy.

4. Maintenance Therapy

A targeted medicine may continue after initial treatment to help maintain remission or delay cancer progression.

5. Treatment of Advanced or Metastatic Cancer

Targeted therapy may shrink cancer, slow its growth, relieve symptoms, preserve function, or extend survival. Some patients experience long-term disease control.

6. Treatment of Recurrent Cancer

Cancer that returns after earlier treatment may contain an actionable target or a new resistance mechanism that can be treated with a different targeted medicine.

7. Treatment of Blood Cancers

Targeted medicines can block abnormal enzymes, receptors, survival proteins, epigenetic regulators, or other features used by leukemia, lymphoma, myeloma, and related blood cancers.

8. Symptom and Disease Control

Even when cure is not expected, targeted therapy may reduce cancer burden and improve or maintain quality of life. Palliative-care services can be provided at the same time.

Targeted therapy may be considered when:

• The cancer has a biomarker linked to an approved targeted treatment.
• The cancer expresses a surface protein recognized by a therapeutic antibody.
• The tumor depends on a particular growth pathway.
• The cancer has a DNA-repair weakness that can be exploited therapeutically.
• The cancer has progressed after previous treatment and repeat testing identifies a new target.
• Targeted treatment can reduce recurrence risk after surgery.
• Treatment can shrink a tumor before surgery.
• A target-based treatment is part of an established combination regimen.
• A biomarker-directed clinical trial is available.

Targeted therapy may not be the preferred treatment when:

• The required target is absent.
• The detected biomarker is not considered actionable for that cancer.
• The biomarker predicts resistance rather than sensitivity.
• The cancer has already developed resistance to the proposed medicine.
• A better-supported surgery, chemotherapy, radiation, hormone therapy, immunotherapy, or surveillance approach is available.
• The patient has a medical condition that creates unacceptable treatment risk.
• A serious interaction cannot be safely managed.
• Organ function does not support safe use of the proposed medicine.
• The expected benefit is small compared with toxicity or treatment burden.
• The patient decides that treatment does not match their goals.

A negative test does not mean that no cancer treatment is available. It may mean that another drug class, combination, clinical trial, or non-targeted treatment is more appropriate.

Precision medicine uses information about genes, proteins, biomarkers, environment, health, and other individual factors to guide prevention, diagnosis, or treatment.

In cancer care, precision medicine may help determine:

• Which treatment is most likely to help
• Which medicine is unlikely to work
• Whether a treatment requires a specific biomarker
• Whether a person may qualify for a clinical trial
• Whether repeat testing is appropriate after resistance
• Whether an inherited cancer-risk evaluation is needed

Precision medicine does not mean that every treatment is made uniquely for one person. Many patients with the same actionable cancer feature may receive the same targeted medicine.

Personalized care also includes patient priorities, organ function, previous treatments, other illnesses, daily responsibilities, treatment access, and quality-of-life goals.

Biomarker testing looks for genes, proteins, receptors, mutations, amplifications, fusions, rearrangements, or other characteristics that may provide information about a cancer.

A biomarker may be:

• Predictive: Suggests whether a treatment is more or less likely to work
• Prognostic: Provides information about how the cancer may behave
• Diagnostic: Helps identify or classify the cancer
• Monitoring-related: Helps follow treatment response or recurrence

A treatment biomarker may identify:

• A mutation that activates a growth protein
• A gene fusion producing an abnormal enzyme
• Extra copies of a cancer-driving gene
• Overproduction of a surface receptor
• A defective DNA-repair pathway
• A resistance mutation
• A target that can be recognized by an antibody-drug conjugate

National Cancer Institute: Biomarker Testing for Cancer Treatment

Tumor-Tissue Testing

Tissue obtained during a biopsy or surgery can be tested for cancer-related proteins and genetic changes. Tissue testing also allows the pathologist to confirm the diagnosis and evaluate the tumor’s cellular features.

Liquid Biopsy

A liquid biopsy usually examines fragments of tumor DNA circulating in the bloodstream. It may be useful when tissue is difficult to obtain, when faster testing is needed, or when clinicians are looking for resistance changes.

A negative liquid-biopsy result may occur because the tumor is releasing too little DNA into the blood. In selected situations, tissue testing may still be needed.

Immunohistochemistry

Immunohistochemistry uses antibodies to detect particular proteins in tumor tissue. It may help measure receptor expression, protein loss, or tumor classification.

In Situ Hybridization

Fluorescence or other in situ hybridization methods can detect gene amplification, deletion, fusion, or rearrangement in cells.

Polymerase Chain Reaction

PCR-based testing can rapidly detect selected mutations, fusions, or other known changes.

Next-Generation Sequencing

Next-generation sequencing can examine many genes at the same time. Panels differ in the genes, alteration types, and technical methods they include.

RNA and Protein Testing

RNA-based methods may be especially helpful for detecting selected gene fusions. Protein-based tests may show whether a molecular change is producing an abnormal or overexpressed protein.

No single test detects every possible cancer change. Ask what the test covers, what it does not cover, whether the sample was adequate, and whether confirmatory testing is needed.

A report may identify:

• Actionable alteration: A change with evidence supporting a treatment or clinical trial
• Resistance biomarker: A change suggesting that a particular medicine is unlikely to work
• Variant of uncertain significance: A change whose clinical meaning is not established
• No actionable alteration detected: The test did not identify a currently usable treatment match
• Inadequate or insufficient sample: The laboratory could not obtain a reliable result

Ask the oncology team:

• Is the result clearly linked to an approved treatment for my cancer?
• Is the evidence from my cancer type or a different cancer?
• Does the alteration predict benefit, resistance, or neither?
• Is the finding present in most cancer cells or only a small proportion?
• Should the result be confirmed by another method?
• Does the finding qualify me for a clinical trial?
• Could the result suggest an inherited mutation?

A variant of uncertain significance should not automatically be treated as a proven cancer driver or inherited cancer-risk finding.

Somatic or tumor changes develop within cancer cells and are generally not present in every cell of the body. These changes are not automatically inherited or passed to children.

Germline changes are inherited or arise in an egg or sperm and are present throughout the body. They may affect cancer risk and have implications for biological relatives.

Tumor testing can sometimes detect a change that may be inherited, but tumor testing alone may not establish whether it is germline. Confirmatory testing using blood, saliva, or another non-tumor sample may be recommended.

Genetic counseling can help explain consent, privacy, family implications, testing options, insurance considerations, and appropriate communication with relatives.

• Small-molecule inhibitors: Enter cells and block enzymes or signaling proteins.
• Monoclonal antibodies: Bind targets on cancer cells, immune cells, blood vessels, or circulating molecules.
• Antibody-drug conjugates: Link an antibody to a potent anticancer drug.
• Bispecific antibodies: Bind two targets at the same time.
• Angiogenesis inhibitors: Interfere with signals used to form or maintain tumor blood vessels.
• DNA-repair inhibitors: Exploit weaknesses in the cancer cell’s ability to repair genetic damage.
• Cell-cycle inhibitors: Block proteins that control progression through cell division.
• Apoptosis regulators: Restore or promote programmed cancer-cell death.
• Epigenetic therapies: Alter proteins that regulate which genes are switched on or off.
• Proteasome inhibitors: Disrupt the cancer cell’s protein-disposal system.
• Hormone-pathway therapies: Target hormone production or signaling and are often discussed separately as hormone therapy.
• Targeted radiopharmaceuticals: Carry radioactive treatment to cells with a particular target and are also considered a form of systemic radiation therapy.

Small-molecule medicines are chemically small enough to enter cells and interfere with internal proteins or enzymes. Many are taken as tablets or capsules.

Small molecules may inhibit:

• Receptor tyrosine kinases
• Intracellular signaling kinases
• Cell-cycle proteins
• DNA-repair enzymes
• Proteasomes
• Epigenetic regulators
• Proteins preventing programmed cell death
• Metabolic enzymes used by cancer cells

A medicine ending in “-ib” is often an inhibitor, but the name ending alone does not tell patients the full mechanism, approved use, interaction profile, or safety requirements.

Small-molecule treatments can be convenient to take at home, but they require the same seriousness as infused cancer therapy.

Monoclonal antibodies are laboratory-made proteins designed to bind a particular target. They are usually too large to enter cells and commonly act on a cell-surface receptor, antigen, blood-vessel signal, or circulating molecule.

An antibody may:

• Block a growth receptor
• Prevent a receptor from receiving its activating signal
• Cause the receptor to be removed from the cell surface
• Mark the cancer cell for immune destruction
• Block blood-vessel growth
• Carry a drug, toxin, or radioactive substance to the cancer cell
• Bring an immune cell into contact with a cancer cell

Antibodies are generally given by intravenous infusion or injection. Treatment schedules range from weekly to every several weeks, depending on the product.

Some monoclonal antibodies are classified as targeted therapy, immunotherapy, or both.

An antibody-drug conjugate, or ADC, combines three components:

• An antibody that recognizes a cancer-associated target
• A linker connecting the antibody and drug
• A potent anticancer payload

After the antibody binds to the target, the conjugate may be taken into the cancer cell and release its payload. Some ADCs also produce a “bystander effect,” allowing drug to affect nearby cells.

ADC side effects depend on the antibody target, linker, payload, dose, and tissues that express the target. Possible effects include low blood counts, nausea, fatigue, hair loss, neuropathy, eye problems, liver changes, bleeding, or lung inflammation.

An ADC is not side-effect-free chemotherapy. Its payload may be a powerful cytotoxic drug delivered through a targeted antibody.

A bispecific antibody binds two different targets. It may:

• Block two cancer-growth pathways
• Bind two parts of one receptor system
• Bring a T cell or another immune cell directly to a cancer cell
• Improve target binding or immune activation

Some bispecific antibodies behave primarily as immune-cell engagers and can cause cytokine release syndrome, neurologic effects, infection, and blood-count changes. Others have different target-specific toxicity.

Patients should ask whether the proposed bispecific treatment is being used mainly as targeted therapy, immunotherapy, or both—and which emergency symptoms are specific to that product.

Tumors need blood vessels to receive oxygen and nutrients. Angiogenesis inhibitors block signals involved in forming or maintaining those vessels.

Some treatments block vascular endothelial growth factor, or VEGF. Others block VEGF receptors or several related kinases.

Important possible effects include:

• High blood pressure
• Protein in urine
• Bleeding
• Blood clots
• Slow or impaired wound healing
• Heart effects
• Kidney effects
• Rare gastrointestinal perforation or abnormal internal connection

Tell both the oncologist and surgeon about every planned operation, biopsy, dental procedure, or wound-healing problem. Drug-specific instructions determine when treatment should be held and restarted.

HER2

HER2 is a growth receptor that can be overexpressed or amplified in selected breast, stomach, esophageal, lung, and other cancers. Treatment may involve antibodies, small-molecule inhibitors, or antibody-drug conjugates.

EGFR

EGFR is a growth-signaling receptor. Selected lung cancers with activating EGFR mutations can be treated with EGFR inhibitors. EGFR-targeting antibodies are also used in selected colorectal and head and neck cancers.

ALK, ROS1, RET and NTRK Fusions

Gene fusions can produce continuously active signaling proteins. Specific inhibitors may be used when an eligible fusion is present.

BRAF and MEK

The BRAF-MEK pathway controls cell growth. Selected cancers with activating BRAF alterations may be treated using a BRAF inhibitor, frequently combined with a MEK inhibitor.

KRAS

KRAS was historically difficult to target, but medicines now inhibit selected KRAS alterations in particular cancers. The exact KRAS variant and treatment setting matter.

MET and FGFR

Abnormal MET or FGFR signaling can drive selected lung, bladder, bile-duct, blood, and other cancers. Eligibility may require a mutation, amplification, fusion, rearrangement, or exon-skipping alteration.

KIT and PDGFRA

These kinases are important targets in gastrointestinal stromal tumors and selected blood or mast-cell disorders. The specific mutation can influence treatment choice and sensitivity.

BCR-ABL

BCR-ABL is an abnormal fusion protein central to chronic myeloid leukemia and selected acute lymphoblastic leukemias. Tyrosine-kinase inhibitors transformed treatment of these cancers.

BRCA and Homologous-Recombination Repair

Some cancers have weakened repair of double-strand DNA damage. PARP inhibitors can exploit this weakness in selected ovarian, breast, prostate, pancreatic, and other cancer settings.

CDK4 and CDK6

CDK4/6 proteins help cells move through the cell cycle. Inhibitors are widely used with hormone therapy in selected hormone-receptor-positive breast cancers.

PI3K, AKT and mTOR

This pathway regulates growth, metabolism, and survival. Medicines targeting different parts of the pathway are used in selected solid and blood cancers.

BTK, BCL-2 and Other Blood-Cancer Targets

B-cell cancers may depend on B-cell receptor signaling or anti-death proteins. BTK and BCL-2 inhibitors are examples of targeted approaches used in selected leukemias and lymphomas.

IDH

Mutated IDH enzymes produce an abnormal metabolite that alters cell development. IDH inhibitors are used in selected leukemias, bile-duct cancers, brain tumors, and other settings.

Proteasome and Epigenetic Targets

Proteasome inhibitors disrupt protein disposal, while epigenetic medicines alter gene regulation. These approaches are particularly important in selected blood cancers.

The following examples are educational and not a complete list. Eligibility depends on cancer subtype, stage, biomarker, previous treatment, organ function, and current regulatory approval.

• Breast cancer: HER2-directed therapy, CDK4/6 inhibitors, PI3K or AKT pathway inhibitors, PARP inhibitors, and antibody-drug conjugates in selected settings
• Lung cancer: Treatments for selected EGFR, ALK, ROS1, BRAF, MET, RET, NTRK, KRAS, HER2, and other alterations
• Colorectal cancer: EGFR, VEGF, BRAF, HER2, KRAS, and other targeted strategies in biomarker-selected disease
• Melanoma: BRAF and MEK pathway inhibitors in selected BRAF-altered tumors
• Chronic myeloid leukemia: BCR-ABL tyrosine-kinase inhibitors
• Acute leukemias: Treatments targeting selected BCR-ABL, FLT3, IDH, CD33, BCL-2, and other abnormalities
• Lymphoma and chronic lymphocytic leukemia: BTK, BCL-2, PI3K, CD20, and other target-directed treatment
• Multiple myeloma: Proteasome inhibitors, antibodies, antibody-drug conjugates, and other molecularly directed approaches
• Gastrointestinal stromal tumor: KIT- or PDGFRA-directed kinase inhibitors
• Kidney cancer: VEGF-receptor, mTOR, HIF-2, and combination targeted strategies
• Ovarian cancer: PARP inhibitors, angiogenesis inhibitors, and target-directed antibody-drug conjugates in selected settings
• Prostate cancer: PARP inhibitors, androgen-pathway medicines, targeted radiopharmaceuticals, and other selected treatments
• Thyroid cancer: RET, BRAF, MEK, VEGF-receptor, and other kinase inhibitors in selected disease
• Bladder cancer: FGFR-directed treatment and antibody-drug conjugates in selected settings
• Bile-duct cancer: FGFR, IDH, HER2, BRAF, NTRK, and other biomarker-directed treatment
• Brain tumors: IDH, BRAF, MEK, mTOR, and other targeted approaches for selected tumor types
• Neuroendocrine tumors: mTOR inhibitors, angiogenesis inhibitors, and receptor-targeted radiopharmaceutical treatment
• Pediatric cancers: Targeted treatments for selected BRAF, NTRK, ALK, RET, mTOR-pathway, and other alterations

National Cancer Institute: Targeted Therapy Drug List by Cancer Type

Most cancer medicines are approved according to both the cancer type and treatment setting. A tumor-agnostic approval is based primarily on a molecular feature found across several tumor types rather than only the organ where the cancer began.

Examples of targets that may support tumor-agnostic treatment in selected circumstances include particular NTRK fusions, RET fusions, BRAF alterations, or HER2 expression or mutation patterns.

Tumor-agnostic does not mean unrestricted. Eligibility may still depend on:

• The exact biomarker and testing method
• Age
• Whether the cancer is advanced or cannot be surgically removed
• Previous treatments
• Whether satisfactory alternatives exist
• Organ function
• The approved drug label

The original tumor type remains important because cancer behavior, treatment combinations, resistance, and side effects can differ even when the same target is present.

The oncology team considers:

• The exact cancer type, subtype, stage, and grade
• The biomarker and testing method
• How strong the evidence is for targeting that biomarker
• Whether the medicine is approved for that clinical setting
• The treatment goal
• Previous therapies and responses
• Known or suspected resistance mechanisms
• Heart, lung, liver, kidney, blood-count, eye, and nerve function
• Other medicines and possible interactions
• Planned surgery, procedures, or dental treatment
• Pregnancy and fertility considerations
• The patient’s preferences, access, schedule, and cost

The plan should identify the medicine’s generic name, target, treatment goal, route, dose, schedule, monitoring requirements, likely side effects, interaction precautions, and conditions for dose adjustment or treatment discontinuation.

Oral Treatment

Many small-molecule targeted medicines are tablets or capsules taken at home. They may be taken once or several times daily, continuously, or on a repeating schedule.

Intravenous Infusion

Monoclonal antibodies, antibody-drug conjugates, and some other therapies are given through a vein. Treatment may use a temporary IV, port, or central catheter.

Subcutaneous Injection

Selected targeted antibodies or combination products are injected under the skin.

Intramuscular or Local Administration

Less commonly, treatment may be injected into a muscle, tumor, body cavity, or another local site.

Targeted Radiopharmaceutical Administration

A radioactive targeted medicine may be swallowed or infused. Radiation-safety precautions may apply and are covered more fully in the Cancer Source Radiation Therapy guide.

Targeted treatment may be given:

• Once or several times each day
• Continuously without a planned break
• For several days followed by a rest period
• Weekly
• Every two, three, four, or more weeks
• For a fixed number of months or years
• Until cancer progresses
• Until side effects become unacceptable
• As maintenance after another treatment

Treatment may be delayed, reduced, interrupted, or stopped because of:

• Severe diarrhea or dehydration
• Liver or kidney changes
• High blood pressure
• Heart or rhythm problems
• Lung inflammation
• Eye or vision effects
• Low blood counts
• Skin or hand-foot toxicity
• Bleeding, clotting, or wound-healing complications
• Drug interactions
• Cancer progression or resistance

A dose reduction or treatment hold does not automatically mean treatment has failed. Many targeted medicines have established dose-modification plans designed to improve safety and treatment continuity.

Understand the Treatment Match

• Ask for the full generic name of the medicine.
• Ask which molecular target it blocks.
• Review the biomarker report.
• Understand the treatment goal.
• Ask how strong the evidence is for your cancer type and stage.
• Know how response and resistance will be monitored.

Baseline Medical Testing

Depending on the drug, testing may include:

• Complete blood count
• Liver and kidney tests
• Electrolytes and blood sugar
• Urine protein testing
• Blood-pressure measurement
• Electrocardiogram
• Echocardiogram or another heart-function test
• Lung assessment
• Eye examination
• Pregnancy testing
• Infection screening
• Baseline imaging

Review Medicines and Supplements

Provide a complete list of prescriptions, nonprescription medicines, vitamins, herbs, supplements, cannabis products, antacids, acid-reducing medicines, and other substances. Include medicines taken only occasionally.

Discuss Upcoming Procedures

Tell the team about planned surgery, biopsy, dental extraction, endoscopy, implanted-device placement, or another invasive procedure. Certain medicines affect bleeding or wound healing.

Pregnancy and Fertility Planning

Many targeted medicines can harm a developing pregnancy. Discuss contraception, fertility preservation, breastfeeding, and future family planning before treatment.

Prepare for Home Monitoring

The oncology team may recommend:

• A home blood-pressure monitor
• A thermometer
• A symptom and bowel-movement record
• Daily weight measurements
• Medication reminders or a treatment calendar
• Photographs to track skin changes
• Daytime and after-hours oncology numbers

Oral treatment is not automatically milder, safer, or less effective than infused therapy.

Obtain written instructions covering:

• The exact dose
• The days and times it should be taken
• Whether it should be taken with food or on an empty stomach
• Foods, medicines, or supplements to avoid
• Whether tablets may be split, crushed, dissolved, or opened
• What to do after a missed or late dose
• What to do if vomiting occurs after a dose
• What symptoms require withholding a dose and calling the team
• How the medicine should be stored
• How it should be handled by caregivers
• How unused medicine should be returned or discarded

Do not double the next dose unless the oncology team specifically instructs you to do so.

Keep targeted medicines in their original labeled containers unless the oncology pharmacist approves another system. Protect them from heat, moisture, direct sunlight, children, pets, and unauthorized use.

Contact the specialty pharmacy or oncology team before allowing a prescription to run out. Some medicines require prior authorization, limited-distribution pharmacies, or special delivery arrangements.

Many oral targeted therapies are absorbed, activated, or removed through liver enzymes and transport proteins. Another medicine or food can raise drug levels, lower drug levels, or increase side effects.

Potential interaction categories include:

• Strong liver-enzyme inhibitors or inducers
• Acid-reducing medicines
• Blood thinners and antiplatelet medicines
• Medicines affecting heart rhythm
• Blood-pressure medicines
• Seizure medicines
• Antibiotics and antifungal medicines
• Herbal products such as St. John’s wort
• Selected citrus products, including grapefruit, when restricted by the drug label
• Vitamins and mineral supplements

Some treatments must be taken with food, while others must be taken on an empty stomach. Food can substantially change the amount of medicine absorbed.

Do not assume that a pharmacy or clinician outside the oncology center knows every cancer-drug interaction. Tell each prescriber and pharmacist the exact targeted medicine you take.

Before starting any new product—including a short antibiotic course, antacid, pain reliever, cold medicine, vitamin, or herbal supplement—contact the oncology team or oncology pharmacist.

Symptom and Medication Review

The clinician may ask about diarrhea, rash, blood pressure, breathing, bleeding, pain, vision, mouth symptoms, swelling, urination, energy, and missed doses. New prescriptions and supplements should be reviewed.

Laboratory and Vital-Sign Review

Blood counts, liver tests, kidney tests, electrolytes, urine protein, blood pressure, or other results may need approval before treatment continues.

Premedication

Antibodies and antibody-drug conjugates may require antihistamines, corticosteroids, anti-nausea medicines, fever-reducing medicines, or other premedications.

Infusion or Injection

The medicine is administered at the prescribed rate. The team monitors for infusion reactions and target-specific complications.

Before Leaving

The patient should know which medicine was given, when to take home medicines, which side effects require contact, when laboratory tests are due, and whether driving or activity restrictions apply.

Monitoring depends on the drug and may include:

• Complete blood count
• Liver and kidney function
• Electrolytes
• Blood sugar
• Thyroid or other hormone testing
• Urine protein
• Blood pressure
• Electrocardiogram
• Echocardiogram or another heart-function test
• Lung imaging or oxygen measurement
• Eye examinations
• Skin and nail evaluation
• Neurologic assessment
• Drug-level or molecular monitoring in selected cancers

Monitoring may be more frequent when treatment starts, after a dose change, or when a new interaction or side effect appears.

Laboratory tests do not detect every problem. Report symptoms even when recent test results were described as normal.

Treatment response may be evaluated through:

• Physical examinations
• Changes in symptoms and function
• CT, MRI, PET, ultrasound, or other imaging
• Blood tests and tumor markers
• Bone-marrow testing
• Molecular tests measuring cancer-related DNA or transcripts
• Pathology after surgery

Possible response categories include:

• Complete response: No detectable cancer using the current tests
• Partial response: A meaningful reduction in measurable cancer
• Stable disease: No major growth or shrinkage
• Progressive disease: Cancer has grown or new areas have appeared
• Molecular response: A reduction in a cancer-specific molecular marker

Side-effect severity does not show whether treatment is working. A severe rash or diarrhea does not guarantee benefit, and having few side effects does not mean treatment has failed.

Primary resistance means that the cancer does not respond adequately from the beginning. Acquired resistance develops after an initial period of benefit.

Resistance may occur when:

• The target changes shape through a new mutation
• The cancer produces more of the target
• A different growth pathway becomes active
• The cancer loses the target
• Another group of cancer cells without the target grows
• The drug cannot reach the tumor adequately
• The cancer pumps the drug out or breaks it down
• The tumor environment protects cancer cells
• Doses are repeatedly missed or absorption is reduced by an interaction

When cancer progresses, the team may recommend:

• Repeat tissue or liquid-biopsy testing
• A next-generation inhibitor
• A second medicine targeting a bypass pathway
• An antibody-drug conjugate
• Chemotherapy, immunotherapy, hormone therapy, radiation, or surgery
• Treatment directed at a limited resistant tumor site
• A clinical trial

Do not continue or restart an ineffective targeted medicine without oncology guidance. In some situations treatment is continued beyond limited progression, but this requires a deliberate medical plan.

Side effects depend on the target, drug class, dose, combinations, and patient. Possible effects include:

• Diarrhea or constipation
• Rash, dryness, acne-like eruptions, or itching
• Hand-foot skin reaction
• Nail changes
• Mouth sores
• Fatigue
• Nausea or reduced appetite
• High blood pressure
• Liver-test abnormalities
• Low blood counts
• Swelling or fluid retention
• Muscle or joint pain
• Changes in hair texture or color
• Heart or rhythm effects
• Lung inflammation
• Kidney problems or protein in urine
• Eye and vision problems
• Bleeding, clotting, or wound-healing problems
• Infusion or allergic reactions

EGFR-Pathway Inhibitors

Possible effects include acne-like rash, dry skin, nail inflammation, diarrhea, mouth sores, and—in selected medicines—lung or eye effects.

HER2-Directed Treatments

Effects depend on the product and may include infusion reactions, diarrhea, heart-function changes, low blood counts, liver changes, or lung inflammation.

BRAF and MEK Inhibitors

Possible effects include fever, chills, rash, fatigue, diarrhea, heart or eye changes, blood clots, skin tumors, and lung or liver effects.

VEGF and Angiogenesis Inhibitors

Possible effects include high blood pressure, bleeding, blood clots, protein in urine, wound-healing problems, diarrhea, hand-foot reaction, heart effects, and rare perforation.

CDK4/6 Inhibitors

Possible effects include low white blood cells, infection risk, anemia, fatigue, diarrhea, liver changes, blood clots, heart-rhythm changes, or lung inflammation, depending on the medicine.

PARP Inhibitors

Possible effects include fatigue, nausea, low blood counts, appetite changes, and—rarely—serious bone-marrow disorders or blood cancers.

PI3K, AKT and mTOR Inhibitors

Possible effects include high blood sugar, rash, diarrhea, mouth sores, infection, lung inflammation, liver changes, and altered cholesterol or triglyceride levels.

BTK and Related Blood-Cancer Inhibitors

Possible effects include bleeding, infection, low blood counts, diarrhea, high blood pressure, irregular heartbeat, or other heart effects.

BCL-2 Inhibitors

Tumor lysis syndrome can occur when many cancer cells die rapidly. Treatment may require gradual dose increases, hydration, preventive medicines, and close laboratory monitoring.

Proteasome Inhibitors

Possible effects include neuropathy, low blood counts, infection, diarrhea or constipation, heart effects, and reactivation of selected viruses.

Antibody-Drug Conjugates

Side effects reflect both the antibody target and the payload and may include low blood counts, nausea, fatigue, neuropathy, eye problems, liver changes, bleeding, or lung inflammation.

Targeted therapies may cause:

• Acne-like rash
• Dry, itchy, or cracked skin
• Sun sensitivity
• Nail tenderness or infection
• Hair thinning or texture changes
• Eyelash or facial-hair changes
• Redness, pain, peeling, or thickening of palms and soles

Early skin care may include gentle cleansing, regular moisturizing, sun protection, friction reduction, and treatment prescribed by the oncology or dermatology team.

Do not use harsh acne products, strong exfoliants, black salve, unapproved herbal preparations, or caustic substances on a treatment-related rash.

Report blistering, peeling, rapidly spreading rash, facial swelling, mouth sores, eye involvement, fever, or painful skin immediately.

Diarrhea can cause dehydration, kidney problems, electrolyte changes, weight loss, skin injury, and treatment interruption.

Report:

• A significant increase over normal bowel movements
• Nighttime diarrhea
• Blood or black stool
• Severe cramping
• Fever
• Dizziness or very little urine
• Inability to keep fluids down

The team may recommend hydration, dietary adjustments, anti-diarrheal medicine, laboratory testing, infection evaluation, dose interruption, or hospitalization.

Do not automatically treat severe diarrhea with nonprescription medicine without knowing the oncology plan. The cause and recommended treatment differ among targeted therapies.

Angiogenesis inhibitors and other targeted medicines may increase blood pressure. Patients may be asked to measure blood pressure at home and record the results.

Contact the team for:

• Readings above the drug-specific threshold
• Severe headache
• Chest pain
• Shortness of breath
• Confusion
• Vision changes
• New neurologic symptoms

Certain therapies can also increase bleeding or clotting risk. Report unusual bruising, prolonged bleeding, blood in urine or stool, coughing or vomiting blood, one-sided leg swelling, sudden chest pain, or sudden trouble breathing.

Do not begin aspirin, ibuprofen, naproxen, blood-thinning supplements, or another product affecting clotting without oncology approval.

Selected targeted therapies can weaken heart pumping, alter heart rhythm, raise blood pressure, cause fluid retention, or contribute to blood clots.

Possible warning signs include:

• New shortness of breath
• Chest pain
• Rapid, irregular, or pounding heartbeat
• Fainting or severe dizziness
• Sudden weight gain
• Swelling of the feet, legs, hands, or abdomen
• Difficulty breathing while lying flat
• Unusual reduction in exercise tolerance

Monitoring may include electrocardiograms, echocardiograms, blood pressure, electrolytes, and cardiac blood tests.

Tell the team about existing heart disease, rhythm problems, fainting, high blood pressure, and every medicine that can affect heart rhythm.

Some kinase inhibitors, antibody-drug conjugates, mTOR inhibitors, and other targeted medicines can cause interstitial lung disease or pneumonitis.

Report immediately:

• New or worsening cough
• Shortness of breath
• Chest discomfort
• Fever
• Low oxygen reading
• Difficulty completing usual activity

These symptoms can also result from infection, a blood clot, heart problems, fluid, radiation effects, or cancer. Prompt evaluation is necessary.

Do not wait for a scheduled scan when breathing symptoms are new or worsening.

Liver

Liver injury may first appear in blood tests. Possible symptoms include:

• Yellow skin or eyes
• Dark urine
• Pale stool
• Right-sided upper abdominal pain
• Severe nausea
• Unusual bruising
• Marked fatigue or confusion

Kidneys

Targeted therapies can affect kidney filtration, blood vessels, electrolytes, or urine protein. Report:

• Marked reduction in urine
• Blood in urine
• New swelling
• Rapid weight gain
• Severe weakness
• Persistent vomiting or diarrhea

Avoid dehydration and do not begin nonprescription pain medicines or supplements that may affect kidney function without oncology approval.

Selected kinase inhibitors and antibody-drug conjugates can affect the cornea, retina, tear production, visual focus, or tissue around the eyes.

Report:

• New blurred vision
• Eye pain or redness
• Light sensitivity
• Flashes, floaters, or missing areas of vision
• Sudden reduction in vision
• Severe dry eye
• Swelling around the eyes

Some medicines require baseline and repeat eye examinations. Lubricating drops or other preventive care may be recommended.

Do not drive when vision is impaired. Sudden vision loss or severe eye pain requires urgent assessment.

Some targeted therapies lower white blood cells, red blood cells, or platelets.

• Low neutrophils: Increased infection risk
• Anemia: Fatigue, weakness, dizziness, or breathlessness
• Low platelets: Bruising or bleeding risk

Report fever at or above the oncology team’s threshold, shaking chills, infection symptoms, uncontrolled bleeding, or severe weakness.

Tumor Lysis Syndrome

When an effective therapy rapidly destroys many cancer cells, their contents can enter the blood and disrupt potassium, phosphorus, calcium, uric acid, kidney function, and heart rhythm. This is called tumor lysis syndrome.

High-risk patients may need hydration, preventive medicine, gradual dose increases, frequent blood tests, or hospital monitoring.

Tell the nurse immediately during an infusion if you develop:

• Itching, hives, flushing, or rash
• Fever, chills, or shaking
• Chest or throat tightness
• Trouble breathing or wheezing
• Facial, lip, or tongue swelling
• Dizziness or fainting
• Sudden back, chest, or abdominal pain
• Rapid heartbeat

The infusion may be paused while the team evaluates and treats the reaction. Depending on severity, treatment may restart more slowly, require additional premedication, be changed, or be permanently discontinued.

Reactions can occasionally occur after leaving the infusion center. Follow the written instructions for delayed symptoms.

Some targeted therapies—especially medicines affecting blood vessels—can interfere with wound healing or increase bleeding, clotting, infection, or perforation risk.

Before a procedure:

• Tell the surgeon and dentist the exact cancer medicine.
• Tell the oncology team the procedure type and date.
• Ask whether and when treatment must be held.
• Ask when treatment may safely restart.
• Report open wounds, infection, drainage, or delayed healing.

The safe interruption interval differs by medicine, dose, procedure, and healing status.

Never create your own preoperative medication-hold schedule.

Follow the drug-specific instructions supplied by your treatment center. Contact the oncology team immediately for:

• Fever at or above the reporting threshold
• New or worsening shortness of breath or cough
• Chest pain, fainting, or an irregular heartbeat
• Severe headache, confusion, weakness, or vision change
• Severe or persistent diarrhea
• Blood or black material in stool
• Persistent vomiting or inability to keep liquids down
• Severe abdominal pain or sudden abdominal swelling
• Yellow skin or eyes
• Very dark urine or major reduction in urine
• Uncontrolled bleeding or coughing or vomiting blood
• One-sided leg swelling or sudden breathing difficulty
• Rapidly worsening swelling or sudden weight gain
• Severe rash, blistering, peeling, or painful skin
• Facial, tongue, or throat swelling
• Sudden vision loss or severe eye pain
• Markedly elevated blood pressure with symptoms
• Signs of infection around a port, catheter, incision, or wound
• Any reaction specifically identified as urgent in the medication guide

Seek emergency medical care for severe breathing difficulty, loss of consciousness, signs of stroke, uncontrolled bleeding, severe chest pain, seizure, or another immediately life-threatening problem.

Pregnancy

Many targeted medicines can harm an embryo or fetus. Tell the oncology team immediately if you are pregnant, could be pregnant, or become pregnant during treatment.

Contraception

Patients who could become pregnant or cause a pregnancy should ask which contraception is recommended and how long it should continue during and after treatment. The required period differs by medicine.

Fertility

Fertility effects are not fully known for every targeted treatment. Risk may also come from chemotherapy, radiation, surgery, hormone changes, or the cancer itself.

Ask about sperm banking, egg or embryo freezing, ovarian-tissue preservation, and other options before treatment when future biological parenthood matters.

Breastfeeding

Many targeted medicines may pass into breast milk or pose an unknown risk. Ask whether breastfeeding must stop and for how long.

Sexual Health

Fatigue, diarrhea, skin changes, hormonal effects, pain, body-image concerns, and other cancer treatments may affect sexual health. Ask about reproductive, endocrine, pelvic-floor, counseling, or sexual-medicine support.

Targeted Therapy and Chemotherapy

Chemotherapy may broadly destroy rapidly dividing cells while targeted therapy blocks a specific pathway or receptor. Combined treatment may improve cancer control but can also increase blood-count, digestive, skin, nerve, or organ effects.

Targeted Therapy and Immunotherapy

Targeted treatment may alter the tumor environment or release antigens in ways that support immune attack. Combinations can also increase liver, lung, skin, bowel, blood-pressure, and other toxicities.

Targeted Therapy and Hormone Therapy

Targeted medicines are commonly combined with hormone therapy in selected breast, prostate, uterine, and other hormone-sensitive cancers.

Targeted Therapy and Radiation

Some targeted medicines make cancer cells more sensitive to radiation. The combination may also intensify skin, bowel, lung, liver, brain, or other tissue effects.

Targeted Therapy and Surgery

Treatment may be given before surgery to shrink cancer or after surgery to reduce recurrence risk. Timing must account for bleeding, wound healing, infection, and organ effects.

Two Targeted Therapies Together

Blocking two levels of one pathway or two different pathways may improve response and delay resistance. Combination therapy can also produce new or more severe side effects.

Some targeted therapies are taken for months or years. Long-term treatment requires attention to both cancer control and cumulative toxicity.

Long-term monitoring may address:

• Heart function
• Blood pressure
• Kidney and liver health
• Blood counts
• Lung symptoms
• Eye health
• Skin and nail problems
• Bone and metabolic health
• Fertility and hormone effects
• Medication adherence and interactions
• Resistance and disease progression
• Rare secondary cancers or bone-marrow disorders associated with selected treatments

Patients should request a treatment summary listing:

• The exact target and biomarker
• The medicine and treatment dates
• Highest and final doses
• Dose interruptions or reductions
• Important side effects
• Heart, lung, eye, liver, kidney, or other monitoring needs
• Known resistance findings
• Future surveillance recommendations

Keep biomarker reports and treatment summaries permanently because they may guide future therapy.

Nutrition

Nutrition supports strength, healing, treatment tolerance, and quality of life. Report reduced appetite, unplanned weight loss, taste changes, mouth pain, diarrhea, vomiting, swallowing difficulty, or inability to prepare food.

Food Timing

Follow the medication’s exact food instructions. Taking a drug with food when it requires fasting—or fasting when it requires food—can alter absorption and toxicity.

Hydration

Diarrhea, vomiting, fever, poor intake, kidney effects, and high blood sugar can cause dehydration. Fluid recommendations should be individualized for patients with heart, kidney, or liver problems.

Physical Activity

Safe, appropriately paced movement may support strength, mood, sleep, and fatigue management. Activity should be adjusted for anemia, heart or lung effects, neuropathy, dizziness, blood clots, bone disease, high blood pressure, or fall risk.

Supportive and integrative care may help patients manage fatigue, anxiety, pain, sleep, nutrition, mobility, and treatment-related stress while evidence-based cancer treatment continues.

Depending on medical approval, services may include:

• Oncology nutrition
• Physical and occupational therapy
• Supervised exercise
• Dermatology or specialized skin care
• Mindfulness and relaxation practices
• Psychological counseling
• Support groups
• Spiritual care based on patient preference
• Massage adapted for oncology patients
• Acupuncture for selected symptoms
• Palliative care for symptom management and quality of life

Complementary approaches should not replace biomarker-directed cancer treatment or urgent evaluation of possible toxicity.

Avoid unverified cancer cures, detox products, black salve, coffee enemas, restrictive starvation diets, or high-dose supplement programs. Supplements can alter targeted-drug levels, worsen liver or kidney injury, increase bleeding, or reduce treatment effectiveness.

National Center for Complementary and Integrative Health: Cancer and Complementary Approaches

Some people continue working or attending school during targeted therapy. Others need reduced hours, remote work, medical leave, disability accommodations, or help with transportation.

Daily-life planning may need to account for:

• Fatigue
• Diarrhea or frequent bathroom needs
• Skin sensitivity
• Blood-pressure monitoring
• Frequent laboratory appointments
• Infusion schedules
• Infection or bleeding risk
• Vision or heart-rhythm effects
• Medication timing and refrigeration requirements

Travel

Discuss travel before booking. Ensure adequate medicine supply, temperature-controlled storage when required, insurance authorization, laboratory access, emergency care, and a plan for lost or delayed medication.

Driving

Do not drive when affected by dizziness, faintness, confusion, vision changes, severe fatigue, sedating medicines, neuropathy, or another condition that makes driving unsafe.

Bring a written list, take notes, and consider bringing a trusted support person. Useful questions include:

1. What is the exact name and subtype of my cancer?
2. What is the stage and treatment goal?
3. What is the full generic name of the targeted medicine?
4. What protein, gene, receptor, or pathway does it target?
5. Which biomarker test supports this treatment?
6. Can I receive a copy of the biomarker report?
7. Was testing performed on tissue, blood, or both?
8. Was the sample adequate?
9. Does the biomarker clearly predict benefit?
10. Does the result indicate resistance to another treatment?
11. Could the result represent an inherited mutation?
12. Should I meet with a genetic counselor?
13. How likely is the treatment to help in my situation?
14. Which evidence or guideline supports it?
15. Is the medicine approved for my cancer and treatment setting?
16. What alternatives are available?
17. What may happen without targeted therapy?
18. Will treatment be used alone or with chemotherapy, immunotherapy, hormone therapy, radiation, or surgery?
19. How is the medicine given?
20. What is the exact dose and schedule?
21. Should oral doses be taken with food or on an empty stomach?
22. What should I do if I miss a dose?
23. What should I do if I vomit after taking it?
24. May the tablet or capsule be split, crushed, opened, or dissolved?
25. Which foods, medicines, antacids, vitamins, and supplements should I avoid?
26. Could any of my current medicines change the drug level?
27. Which baseline tests do I need?
28. Will I need blood-pressure, heart, lung, eye, urine, liver, kidney, or blood-count monitoring?
29. What side effects are most likely?
30. Which side effects could be permanent or life-threatening?
31. Which symptoms require an immediate call?
32. Whom should I contact at night or on weekends?
33. When should a dose be held?
34. What would lead to a dose reduction or permanent stop?
35. Could treatment affect surgery, dental work, bleeding, or wound healing?
36. Could treatment affect fertility or pregnancy?
37. What contraception is recommended, and for how long?
38. Is breastfeeding safe?
39. How will you determine whether treatment is working?
40. When will scans or molecular tests be repeated?
41. How might the cancer become resistant?
42. Would repeat tissue or liquid-biopsy testing be useful after progression?
43. Could a clinical trial be appropriate?
44. Can I meet with an oncology pharmacist, dietitian, dermatologist, rehabilitation professional, fertility specialist, social worker, counselor, or financial navigator?
45. Will I receive a written treatment and survivorship summary?

Myth: Targeted therapy attacks only cancer cells.

Fact: Healthy cells may use the same target or pathway, so targeted therapy can cause significant side effects.

Myth: Every cancer has a targetable mutation.

Fact: Testing may find no actionable target, and some cancers lack an established targeted treatment.

Myth: Finding a matching mutation guarantees that treatment will work.

Fact: Response also depends on whether the alteration drives the cancer, the treatment setting, other cancer changes, drug delivery, and resistance.

Myth: Any mutation listed on a report can be treated.

Fact: Some findings are not actionable, and variants of uncertain significance do not have established treatment meaning.

Myth: Oral targeted therapy is weaker than infused therapy.

Fact: Oral targeted medicines can be powerful and require strict dosing, interaction review, and monitoring.

Myth: More side effects mean the medicine is working better.

Fact: Side-effect severity does not prove treatment effectiveness.

Myth: Having no side effects means the medicine has failed.

Fact: Response is measured through examinations, imaging, laboratory tests, pathology, and molecular monitoring.

Myth: A negative liquid biopsy proves that no target exists.

Fact: Some tumors release too little DNA into the blood. Tissue testing may still be appropriate.

Myth: Tumor mutations are always inherited.

Fact: Many mutations are limited to cancer cells. Separate germline testing may be needed to determine whether a finding is inherited.

Myth: Supplements cannot interfere with precision treatment.

Fact: Herbal products, vitamins, antacids, and other medicines can raise or lower targeted-drug levels and change safety or effectiveness.

Current research includes:

• New inhibitors for previously difficult targets
• Next-generation drugs designed to overcome resistance
• Combination treatments blocking multiple pathways
• Protein degraders that cause cancer-driving proteins to be destroyed
• New antibody-drug conjugates
• Bispecific and multispecific antibodies
• Targeted radiopharmaceuticals
• Liquid-biopsy monitoring
• Circulating tumor-DNA-guided treatment
• Artificial intelligence for biomarker interpretation and drug discovery
• Improved treatment for rare molecular alterations
• Basket trials based on a shared biomarker
• Umbrella trials testing several biomarkers within one cancer type
• Adaptive trials that change treatment according to response
• Methods to reduce target-specific toxicity

Questions to ask about a trial include:

• What biomarker or target is required?
• How strong is the evidence that this target drives my cancer?
• Is the drug approved for another cancer or fully investigational?
• How does the trial compare with standard treatment?
• Is a new biopsy required?
• What are the known and uncertain risks?
• What extra visits, costs, or travel are involved?
• What treatment is available if I do not participate?

National Cancer Institute: Find Cancer Clinical Trials

A second opinion may confirm the treatment match, identify missing biomarker testing, clarify a complex report, or provide access to a specialized clinical trial.

A second opinion may be especially helpful when:

• The cancer is rare.
• The molecular finding is unusual.
• The report contains several possible targets.
• The alteration is classified differently by different laboratories.
• A variant of uncertain significance is being discussed as a treatment target.
• The treatment would be outside the usual approved setting.
• The cancer progressed after an initially effective targeted therapy.
• Repeat testing or a new biopsy is being considered.

Some cancer centers use a molecular tumor board, where oncologists, pathologists, geneticists, pharmacists, laboratory specialists, and researchers review complex biomarker findings.

National Cancer Institute: Find an NCI-Designated Cancer Center

Costs vary according to the medicine, treatment schedule, testing, facility, pharmacy, insurance, monitoring, toxicity management, and treatment duration.

Potential expenses include:

• Biomarker testing
• Tissue or liquid biopsy
• Oral specialty-pharmacy medicine
• Infusion-center or hospital charges
• Laboratory and imaging tests
• Heart, eye, or other specialist monitoring
• Supportive medicines
• Emergency or hospital care
• Travel, lodging, parking, or child care
• Reduced work hours or medical leave

Before treatment, ask:

• Is biomarker testing covered?
• Is prior authorization required?
• Must I use a specialty or limited-distribution pharmacy?
• Is the treatment billed under the medical or pharmacy benefit?
• Are the oncologist, laboratory, imaging center, and infusion facility in network?
• Is copayment or manufacturer assistance available?
• What happens if insurance authorization is delayed?
• Can a financial navigator estimate total out-of-pocket costs?

National Cancer Institute: Tracking and Managing Cancer-Care Costs

• □ I know the goal of targeted therapy.
• □ I know the full generic name of the medicine.
• □ I know which protein, gene, receptor, or pathway it targets.
• □ I have a copy of my biomarker report.
• □ I understand whether the finding is actionable.
• □ I know whether inherited genetic testing is recommended.
• □ I understand the dose, route, and schedule.
• □ I know whether oral treatment is taken with food or while fasting.
• □ I know what to do after a missed dose or vomiting.
• □ I provided a complete medicine and supplement list.
• □ I know which food and drug interactions to avoid.
• □ I told the team about planned surgery and dental procedures.
• □ Pregnancy, contraception, fertility, and breastfeeding were discussed.
• □ I understand the most likely side effects.
• □ I know which symptoms require immediate contact.
• □ I have daytime and after-hours oncology numbers.
• □ I know which blood tests and scans are required.
• □ I understand blood-pressure, heart, lung, eye, kidney, or liver monitoring.
• □ I know how treatment response will be measured.
• □ I know whether repeat biomarker testing may be needed after progression.
• □ I will request a treatment and survivorship summary.

• National Cancer Institute — Targeted Therapy for Cancer
• National Cancer Institute — Targeted Therapy Drug List by Cancer Type
• National Cancer Institute — Biomarker Testing for Cancer Treatment
• National Cancer Institute — A-to-Z List of Cancer Drugs
• National Cancer Institute — Cancer Types and Treatment Summaries
• National Cancer Institute — Tumor Markers
• National Cancer Institute — Cancer Genetics
• American Cancer Society — Targeted Therapy
• American Cancer Society — Targeted Therapy Side Effects
• Cancer Research UK — Targeted Cancer Drugs
• Canadian Cancer Society — Targeted Therapy
• MedlinePlus — Cancer Targeted Therapies
• U.S. Food and Drug Administration — Oncology Prescription Drug Labeling
• U.S. Food and Drug Administration — Oncology Approval Notifications
• National Center for Complementary and Integrative Health — Cancer and Complementary Approaches
• National Cancer Institute — Find an NCI-Designated Cancer Center
• National Cancer Institute — Find Cancer Clinical Trials

Targeted therapy is not one medicine, one biomarker, or one treatment experience. It includes small-molecule inhibitors, antibodies, antibody-drug conjugates, angiogenesis inhibitors, DNA-repair treatments, cell-cycle inhibitors, and other approaches designed for different molecular targets.

For selected patients, targeted therapy can produce major and sometimes long-lasting responses. It may cure certain cancers, reduce recurrence risk, shrink a tumor before surgery, maintain remission, or control advanced disease.

A biomarker match is the beginning of treatment interpretation—not the end. Safe and effective care depends on understanding whether the target truly drives the cancer, whether the medicine is supported for the clinical setting, and how resistance, interactions, organ function, adherence, and side effects will be monitored.

Patients and families deserve a clear explanation of the treatment target, biomarker result, expected benefit, alternatives, schedule, interaction precautions, short- and long-term risks, emergency plan, costs, and how the oncology team will determine whether treatment is working.