Medical Oncologist
Understanding targeted therapy
How Does Targeted Therapy — Actually Work?
You may have been told targeted therapy is an option for you, but left the appointment still unsure what that means. The explanation uses words like receptor, mutation and pathway — words that sound precise but feel abstract when you are trying to make sense of a new diagnosis. This page explains what they actually mean.
Medically reviewed by Dr. T. Raghavender Reddy, Medical Oncologist, MBBS · DM (Medical Oncology) · MD (Radiation Oncology) · Last reviewed August 2026
- Different from chemotherapy — Targeted therapy does not attack all dividing cells. It looks for a specific molecular feature on the cancer cell that healthy tissue largely does not carry.
- Testing comes first — Before treatment starts, your tumour tissue is tested to identify which protein it carries. That result decides which drug, if any, applies to you.
- The target is a protein — Cancer cells often depend on abnormal proteins to keep growing. Targeted therapy is designed to block those specific proteins and disrupt that process.
- Not every cancer has a usable target — If testing shows no actionable target, targeted therapy is not the right approach — and a different treatment is likely to fit your situation better.
17+
Cancer Specialists
on Panel
on Panel
96.9%
Breast Cancer
Survival Rate*
Survival Rate*
15,000+
Patients
Treated
Treated
4.8★
Google Rating
(800+ reviews)
(800+ reviews)
Targeted therapy uses drugs designed to attach to specific proteins on or inside cancer cells — proteins the tumour depends on to grow and divide. By blocking those proteins, the drug disrupts the cancer's internal machinery. Healthy cells that do not carry those proteins are largely spared.
How is targeted therapy different from chemotherapy?
Chemotherapy works by attacking all rapidly dividing cells. Cancer cells divide fast, so chemo hits them hard — but so do the cells lining your gut, your hair follicles, and your bone marrow. That is why nausea, hair loss and low blood counts are common chemotherapy side effects.
Targeted therapy does not focus on how fast a cell divides. It looks for a specific protein that the cancer cell carries — one that healthy cells either do not have, or carry only in much smaller amounts. The drug is designed to find that protein and block it.
This means the side effect profile is different — not necessarily milder, but different in character. Which side effects you experience depends on which target the drug is acting on, and your oncology team will tell you what to watch for with your specific treatment.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Interventional Radiologist
Dr. Mohammed Imran
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
You do not have to work this out alone
A 45-minute consultation with a specialist who treats this every week.
What exactly is the protein that targeted therapy aims at?
Proteins control most of what a cell does — when to grow, when to stop, when to divide. Cancer cells often carry mutations that produce abnormal versions of these proteins. Those abnormal proteins can act like a stuck accelerator pedal, telling the cell to keep dividing when it should stop.
A targeted drug is shaped to fit that specific protein, the way a key fits a lock. By attaching to it, the drug blocks the signal the protein sends — and the cancer cell loses the instruction that was driving its growth.
The biomarker testing your oncologist arranges is looking for exactly that protein in your tumour tissue. The result tells the team whether your cancer carries an accessible target and which drug is designed to fit it.
Did you know?
Two people with the same cancer diagnosis can need completely different targeted therapy drugs — or one can be eligible while the other is not — because their tumours carry different proteins at the molecular level.
This is why the cancer type on a pathology report is not enough to decide treatment. NCCN guidance states that treatment selection in molecularly driven cancers must follow the result of biomarker testing, not the tissue of origin alone.
Source: NCCN Guidelines — Principles of Molecular Biomarker Testing
Explore 119 more Targeted Therapy Basics, Testing & Your Cancer Type topics
Foundations & How Targeted Therapy Works
- Adjuvant and Neoadjuvant Targeted Therapy: Treatment Before or After Surgery
- Antibody-Drug Conjugates (ADCs): The Smart Bombs of Cancer Treatment
- Biosimilars and Generic Targeted Therapy Drugs: What They Are
- Can Targeted Therapy Be Combined with Chemotherapy or Radiation?
- Can Targeted Therapy Cure Cancer? An Honest Answer
- First-Line, Second-Line and Beyond: How Treatment Lines Work
- How Doctors Decide Between Chemo, Immunotherapy and Targeted Therapy
- How Does Targeted Therapy Actually Work? Explained Without Jargon
- How Long Does Targeted Therapy Take to Start Working?
- Is Targeted Therapy Painful? What the Treatment Actually Feels Like
- Is Targeted Therapy a Type of Chemotherapy? Clearing Up the Confusion
- Oral Tablets vs IV Infusion Targeted Therapy: What's the Difference?
- Precision Oncology vs Personalised Medicine: Are They the Same Thing?
- Targeted Therapy Success Rates: What the Numbers Really Mean
- Targeted Therapy for Stage 4 Cancer: What You Can Realistically Expect
- Targeted Therapy vs Chemotherapy: 12 Differences That Actually Matter
- Targeted Therapy vs Immunotherapy: Which One Is Right for You?
- The 8 Main Types of Targeted Therapy Drugs (With Examples)
- What Do Cancer Drug Endings Like -nib, -mab and -tinib Mean?
- What Is Targeted Therapy for Cancer? A Complete Patient Guide
- Which Cancers Can Be Treated with Targeted Therapy? Full List
- Why Didn't My Doctor Recommend Targeted Therapy for Me?
Before You Start - Preparation & Baseline
- 25 Questions to Ask Your Oncologist Before Starting Targeted Therapy
- Before You Start Targeted Therapy: The Complete Preparation Checklist
- Dental Check-Up Before Cancer Treatment: Why It Matters
- Financial Planning Before Starting Long-Term Targeted Therapy
- How Long After Surgery Can You Start Targeted Therapy?
- How to Store Your Targeted Therapy Tablets Correctly
- Setting Up a Dosing Routine You Won't Forget
- Should Targeted Therapy Be Taken With Food or on an Empty Stomach?
- Vaccinations Before and During Cancer Treatment
- What to Expect in Your First Month on Targeted Therapy
- Which Baseline Tests Are Done Before Starting a TKI?
- Which of Your Existing Medicines Must Stop Before Targeted Therapy
- Why You Need an ECHO and ECG Before Certain Cancer Drugs
Biomarker & Molecular Testing
- Can Mutation Testing Be Done on an Old Biopsy Block or Slides?
- Cost of NGS and Mutation Testing in India: 2026 Price Guide
- Do I Need Genetic Testing Before Starting Targeted Therapy?
- Germline vs Somatic Testing: The Difference Nobody Explains Properly
- Getting a Second Opinion on Your Genomic Report
- How Long Do Mutation Test Results Take in India? Realistic Timelines
- How to Read Your Molecular Pathology Report, Line by Line
- IHC, FISH, PCR or NGS: Which Mutation Test Is Right for Your Cancer?
- Is Mutation Testing Worth It If I Can't Afford the Drug?
- Liquid Biopsy vs Tissue Biopsy: Which Test Do You Need?
- My Report Says a Mutation Is 'Actionable': What Does That Mean?
- No Mutation Found in My Report: What Are My Options Now?
- Should I Start Chemotherapy While Waiting for Mutation Results?
- Should You Repeat Molecular Testing After Your Cancer Progresses?
- Single-Gene Test or Full Panel? How to Choose Without Wasting Money
- What Are PD-L1, TMB and MSI, and Do They Affect Targeted Therapy?
- What Does 'Variant of Uncertain Significance' (VUS) Mean?
- What Happens If There Isn't Enough Tissue for Mutation Testing?
- What Is NGS (Next-Generation Sequencing) Testing in Cancer?
- What Is a Molecular Tumour Board and Why Should You Want One?
- Which Cancers Should Always Be Tested for Mutations? A Checklist
- ctDNA and MRD Testing: Tracking Cancer Through a Blood Test
Cancer-Type Specific Targeted Therapy
- CML Treatment with TKIs: Living a Normal Life Span
- Cancer of Unknown Primary: Can Molecular Testing Help?
- GIST Treatment: Why This Cancer Changed Targeted Therapy Forever
- Targeted Therapy for Bile Duct Cancer (Cholangiocarcinoma)
- Targeted Therapy for Bladder and Urothelial Cancer
- Targeted Therapy for Brain Tumours and Glioma
- Targeted Therapy for Breast Cancer: HER2, HR+ and Triple Negative
- Targeted Therapy for CLL and Lymphoma
- Targeted Therapy for Cervical and Endometrial Cancer
- Targeted Therapy for Childhood Cancers
- Targeted Therapy for Colorectal Cancer: RAS, BRAF and HER2
- Targeted Therapy for Head and Neck Cancer
- Targeted Therapy for Kidney Cancer (RCC)
- Targeted Therapy for Liver Cancer (HCC)
- Targeted Therapy for Lung Cancer: Every Mutation and Drug Explained
- Targeted Therapy for Melanoma: BRAF and MEK Inhibitors
- Targeted Therapy for Multiple Myeloma
- Targeted Therapy for Neuroendocrine Tumours
- Targeted Therapy for Ovarian Cancer: PARP Inhibitors and Beyond
- Targeted Therapy for Pancreatic Cancer: Limited but Real Options
- Targeted Therapy for Prostate Cancer
- Targeted Therapy for Sarcoma
- Targeted Therapy for Stomach and Gastroesophageal Cancer
- Targeted Therapy for Thyroid Cancer
- Targeted Therapy in AML: Beyond Standard Chemotherapy
- Tumour-Agnostic Drugs: When the Mutation Matters More Than the Organ
Mutation & Target-Specific Pages
- ALK-Positive Lung Cancer: Drugs, Response and What Comes Next
- Antiangiogenic Drugs (VEGF Inhibitors): How Starving a Tumour Works
- BCR-ABL and the Philadelphia Chromosome in CML
- BRAF V600E Mutation: Targeted Therapy Across Multiple Cancers
- BRCA vs HRD Testing: Which One Determines PARP Inhibitor Eligibility?
- BRCA1 and BRCA2 Mutations in Cancer Treatment: PARP Inhibitors
- BTK Inhibitors in CLL and Lymphoma
- CD20, CD38 and Other Antibody Targets in Blood Cancers
- CDK4/6 Inhibitors in Hormone-Positive Breast Cancer
- Co-Mutations: When You Have Two Mutations at Once
- EGFR Exon 20 Insertion: Why It's Different and Harder to Treat
- EGFR Mutation in Lung Cancer: Complete Patient Guide
- ESR1 Mutation: Why Your Hormone Therapy Stopped Working
- FGFR Alterations in Bladder and Bile Duct Cancer
- FLT3 Mutation in AML: What It Means for Your Prognosis
- HER2 Mutation in Lung and Gastric Cancer
- HER2-Low Breast Cancer: A New Category That Changes Treatment
- HER2-Positive Breast Cancer: The Full Targeted Therapy Roadmap
- IDH1 and IDH2 Mutations in Glioma, AML and Bile Duct Cancer
- KIT and PDGFRA Mutations in GIST
- KRAS G12C Mutation: The Target That Was Undruggable for 40 Years
- KRAS Mutation but Not G12C: What Are My Options?
- MET Exon 14 Skipping and MET Amplification Explained
- MSI-High and Mismatch Repair Deficiency: Testing and Treatment
- NRG1, MET, RET and Other Rare Fusions: Where to Get Tested
- NTRK Fusion: One Drug for Many Different Cancers
- Osimertinib: What to Expect, Side Effects and How Long It Works
- PALB2, ATM and Other BRCA-Like Genes: Do They Get the Same Drugs?
- PIK3CA Mutation in Breast Cancer: Alpelisib and What to Expect
- PSMA and AR-Targeted Therapy in Prostate Cancer
- RET Fusion Cancer: Lung, Thyroid and Beyond
- ROS1-Positive Cancer: A Rare Mutation with Excellent Options
- TP53 Mutation: Why There's Still No Targeted Drug for It
- Understanding Variant Allele Frequency (VAF) in Your Report
- What If My Mutation Has No Approved Drug Yet?
- mTOR Inhibitors in Cancer: Everolimus and Temsirolimus
Next step
Still not sure what applies to you?
Send your reports across and a senior medical oncologist will go through what they mean, what is known, and what the options actually are.
Common questions
Frequently asked questions
Why do I need a test before targeted therapy can start?
The test identifies which protein your cancer depends on — and that determines which drug, if any, will work for you. Two people with the same cancer type can have tumours that behave completely differently at the molecular level. Without the test, there is no way to know whether there is a matching drug, or which one to use. The biopsy tissue you have already had is usually enough; a new biopsy is only needed if the original sample was too small or too old.
Can targeted therapy work if I do not have a mutation?
It can, but the cancer still needs to carry a specific target for the drug to act on. Not all targets come from mutations — some cancers overproduce a normal protein rather than an abnormal one, and that overproduction is itself a target. The key point is that testing must show the target is present. If it is not there, the drug has nothing to attach to and will not help.
Will my hair fall out on targeted therapy?
Hair loss is much less common with targeted therapy than with chemotherapy, but it is not impossible. The side effects depend on which specific drug you are taking and which protein it targets. Some targeted therapies cause skin changes — rashes or dry skin — rather than hair loss. Others affect blood pressure, liver function or other organ systems. Ask your oncologist which side effects are expected with your drug and what to watch for.
Is targeted therapy given as a tablet or a drip?
It depends on the specific drug. Some targeted therapies are taken as daily tablets at home, which means no clinic visit on most days. Others are given intravenously in a day-care setting. Some are given as injections under the skin. Your oncologist will explain the form your treatment takes and what the schedule looks like before you start.
What happens if the cancer stops responding to targeted therapy?
Resistance can develop over time — this is one of the known limitations of the approach. When it happens, the cancer has usually changed at the molecular level in a way that means the drug can no longer block its target effectively. Your team may arrange repeat testing to look for what has changed, and there may be another drug suited to the new picture. Resistance does not mean all options are exhausted.
Can targeted therapy be used alongside chemotherapy?
Yes, in some cases. For certain cancer types, the combination is the standard approach rather than targeted therapy alone, because the two treatments work by different mechanisms and can complement each other. Whether this applies to your situation depends on your cancer type, your biomarker results and your general fitness. Your oncologist will explain the specific regimen being considered and what it is intended to achieve.
Does targeted therapy work for all types of cancer?
No. Targeted therapy is only useful where the tumour carries a specific molecular target that a drug is designed to block. Many common cancer types do not have actionable targets in most patients. Being told targeted therapy is not an option is not a statement about how serious your cancer is — it is information about the biology of your tumour, and it means a different treatment is likely to fit you better.
How long does targeted therapy treatment last?
The duration varies and depends on your cancer type, how well you are responding, and whether side effects require a break or a change. Some people take targeted therapy for months, others for considerably longer. The aim is to continue for as long as the treatment is working and you can tolerate it. Your oncologist will review your scans and blood tests regularly and discuss any changes to the plan with you.