Cancer treatment used to mean the same chemotherapy protocol for every patient with the same cancer type, regardless of what was actually driving that person's tumour at a molecular level.
That's changed. Oncologists today can often test a tumour's genetic makeup and choose a drug built to block the exact mutation or protein fuelling it. This approach, targeted therapy for cancer treatment, is now standard of care for a growing list of cancers, from certain lung and breast cancers to specific leukaemias.
This guide explains how targeted therapy works and why it is transforming cancer care across India.
What Is Targeted Therapy for Cancer Treatment?
Targeted therapy is a category of cancer drugs designed to interfere with specific molecules, genes, proteins, or signalling pathways that a particular tumour depends on to grow, divide, or spread. Instead of attacking all rapidly dividing cells in the body (which is how chemotherapy works), a targeted drug is built around a molecular "address" that is present on or inside the cancer cell, and largely absent in healthy tissue.
This personalized approach has transformed survival rates for many cancer types, from lung cancer and breast cancer to melanoma and leukemia. The goal is to give each patient the most effective drug for their specific cancer, reducing side effects and improving outcomes.
How It Differs From Chemotherapy at a Cellular Level
Chemotherapy drugs are largely non-selective, they kill any cell that divides quickly, which is why hair follicles, gut lining, and bone marrow cells (also fast-dividing) take collateral damage alongside the tumour. Targeted therapy drugs bind to a specific receptor or block a specific enzyme pathway, so healthy cells that don't carry that particular molecular marker are largely spared.
This is also why targeted therapy side effects tend to look different from classic chemotherapy side effects, think skin rashes, blood pressure changes, or wound-healing issues, rather than hair loss and severe nausea, though this varies by drug.
How Targeted Therapy Works at the Cellular Level
Targeted drugs generally fall into a few functional categories, often used in combination with surgery, radiation, or chemotherapy rather than as a stand-alone cure:
- Monoclonal antibodies are lab-engineered proteins that latch onto a specific target on the surface of cancer cells, either blocking a growth signal directly or flagging the cell for the immune system to destroy. Trastuzumab, used for HER2-positive breast cancer, is a well-known example.
- Small-molecule inhibitors are oral or IV drugs small enough to enter a cell and block an internal signalling enzyme, commonly a tyrosine kinase, that would otherwise tell the cancer cell to keep dividing. EGFR inhibitors used in certain lung cancers work this way.
- Angiogenesis inhibitors cut off a tumour's blood supply by blocking the signals it uses to grow new blood vessels, effectively starving it of oxygen and nutrients rather than attacking the cancer cell directly.
- Hormone-blocking targeted agents are used where a cancer (commonly hormone-receptor-positive breast cancer or certain prostate cancers) depends on estrogen, progesterone, or testosterone to grow; these drugs either lower hormone levels or block the receptor the cancer relies on.
Targeted Therapy vs Chemotherapy vs Immunotherapy
Patients often confuse these three terms, they are related but mechanistically distinct, and a treatment plan may use more than one. The table below outlines key differences:
| Aspect | Targeted Therapy | Chemotherapy | Immunotherapy |
|---|---|---|---|
| What it acts on | A specific mutation, protein, or pathway in the tumour | All rapidly dividing cells, cancerous or not | The patient's own immune system |
| Selection basis | Biomarker/molecular test result | Cancer type and stage | Cancer type, sometimes PD-L1 expression |
| Common side effects | Skin, blood pressure, wound-healing issues (drug-dependent) | Hair loss, nausea, low blood counts | Fatigue, immune-related inflammation |
| Delivery | Oral pill or IV infusion | Usually IV, sometimes oral | Usually IV infusion |
| Typical use case | Cancer with an identified actionable mutation | Broad-spectrum, often first-line or adjuvant | Cancers responsive to immune checkpoint blockade |
Also Read: Combining Cancer Treatments: Multimodal Therapy Approaches
Many patients receive a combination, chemotherapy to debulk the tumor, followed by targeted therapy for long-term control, or radiation plus targeted drugs for advanced disease.
Which Cancers Respond to Targeted Therapy?
Eligibility depends entirely on whether a patient's tumour carries a mutation or protein marker that a targeted drug is built to act on, cancer type alone doesn't determine this.
| Cancer Type | Common Biomarker | Drug Category |
|---|---|---|
| Breast cancer | HER2-positive, hormone receptor-positive | Monoclonal antibodies, hormone-blocking agents |
| Lung cancer (NSCLC) | EGFR, ALK, ROS1, MET, BRAF mutations | Small-molecule (tyrosine kinase) inhibitors |
| Colorectal cancer | KRAS wild-type, EGFR expression | EGFR inhibitors |
| Chronic myeloid leukaemia | BCR-ABL fusion gene | Tyrosine kinase inhibitors |
| Kidney and liver cancer | VEGF pathway activity | Angiogenesis inhibitors |
| Ovarian cancer | BRCA1/BRCA2 mutations | PARP inhibitors |
Also Read: Cancer Types and Treatment Options: Expert Guide
Am I Eligible? The Biomarker Testing Process Explained
Before any targeted drug is prescribed, the oncology team needs a tissue or blood sample to test for the relevant mutation. This typically happens through:
- Tumour biopsy : a tissue sample sent for molecular/genomic profiling
- Liquid biopsy: a blood-based test detecting circulating tumour DNA, sometimes used when a tissue biopsy isn't feasible or to monitor for resistance mutations later
- Immunohistochemistry (IHC) and FISH testing: commonly used to confirm HER2 status in breast cancer, for instance.
Results usually take anywhere from a few days to two to three weeks depending on the complexity of the panel being run and whether it's processed in-house or sent to an external genomic lab.
Once results come back, the oncology team maps the mutation profile to an approved (or clinical-trial) drug, and only then is a targeted regimen finalised, this is why a rushed "start chemo now, figure out biomarkers later" approach is a red flag if a targeted option genuinely exists for that mutation.
Also Read: Targeted Therapy vs Chemotherapy: How to Choose the Right Treatment
Why Choose Baby Memorial Hospital's NAVA Cancer Institute for Targeted Therapy in Kerala
Targeted therapy works best when it's part of a coordinated cancer care plan. At Baby Memorial Hospital's NAVA Cancer Institute, Kozhikode, patients have access to multiple oncology specialties and advanced diagnostics under one roof, making it easier to move from biomarker testing to personalised treatment without unnecessary delays.
Why patients choose NAVA Cancer Institute:
- Medical, surgical, radiation, haemato-, paediatric oncology, and nuclear medicine teams work together.
- Multidisciplinary tumour board reviews for personalised treatment planning.
- Advanced technology including TrueBeam LINAC, Discovery IQ PET-CT, Da Vinci X Robotic Surgery, and GammaMedplus iX Brachytherapy.
- Dedicated chemotherapy day-care, inpatient oncology, and bone marrow transplant support.
- International patient services for Indian and Gulf (UAE, Saudi Arabia, Oman, Qatar, Kuwait, and Bahrain) patients requiring treatment coordination.
Whether you need a second opinion, biomarker testing, or a personalised targeted therapy plan, NAVA Cancer Institute offers comprehensive cancer care designed around your diagnosis and treatment goals.
Chat with our Medical Assistant to connect with our cancer care team, discuss your treatment journey, and schedule a consultation with an oncology specialist.
Medical Disclaimer: This article is intended for general informational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Targeted therapy eligibility, drug selection, dosing, and expected outcomes vary by individual patient, cancer type, stage, and biomarker profile. Always consult a qualified oncologist to evaluate your specific medical situation before making any treatment decisions.