Medical Oncologist
When treatment stops working
Do You Need Another Biopsy — When the Cancer Progresses?
Hearing that the cancer has progressed is frightening. Before deciding what comes next, your oncologist may want to re-test the tumour — because the cancer that is growing now may be biologically different from the one that was diagnosed.
Medically reviewed by Dr. C. Raghavendra Reddy, Medical Oncologist, MBBS (Gold Medal) · DNB · DM (Medical Oncology, Gold Medal) · Last reviewed August 2026
- Tumours can change — The molecular profile of a cancer can shift during treatment, so the original biopsy may no longer describe what is there now.
- Resistance is predictable — Cancer developing resistance to treatment is a known biological process, not a sign that everything has failed.
- Re-testing guides the next step — Knowing which resistance mechanism developed can point your oncologist toward the next-line option most likely to work.
- Blood tests can sometimes substitute — A liquid biopsy detects tumour DNA in a blood sample and may be used when a tissue biopsy is not possible.
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)
When cancer progresses, the tumour may have changed at the molecular level since your first biopsy. A repeat biopsy — or a blood-based liquid biopsy — can identify which resistance mechanism developed and guide which next-line treatment is most likely to work. Whether one is needed depends on your cancer type and the treatment you were on.
Why does cancer stop responding to treatment?
Every time a cancer cell divides, it can acquire small changes in its DNA. Most of those changes are harmless. But occasionally one gives a cell the ability to survive the treatment that is killing its neighbours.
That resistant cell divides, and over weeks to months it can become the dominant population in the tumour. This is called acquired resistance, and it is a predictable biological process — not a failure of care, and not something that could have been prevented.
The result is that the tumour your oncologist is dealing with now may be molecularly different from the one biopsied at diagnosis. A rebiopsy checks whether that has happened and what changed.
When does your oncologist usually recommend a repeat biopsy?
- You were on a targeted therapy and imaging has confirmed progression.
- Your oncologist needs to identify the specific resistance mechanism before choosing next-line treatment.
- A liquid biopsy was inconclusive or detected too little tumour DNA to interpret.
- A clinical trial you may be eligible for requires fresh tissue testing.
- Your cancer type has established rebiopsy guidance at progression from NCCN or ESMO.
- You progressed unexpectedly quickly on immunotherapy and pseudo-progression needs to be ruled out.
What do these terms mean?
- Progression
- When imaging or blood tests show the cancer has grown, spread to new areas, or restarted growing after a period of control.
- Acquired resistance
- A change the tumour develops during treatment that allows it to survive a drug it was previously sensitive to. It is a biological process, not a sign the treatment was wrong.
- Liquid biopsy
- A blood test that detects small fragments of tumour DNA circulating in the bloodstream. It can sometimes identify resistance mutations without needing a tissue sample.
- Next-line therapy
- The treatment plan used after an earlier plan stops working. Most cancer types have more than one line of treatment available.
- Molecular re-testing
- Laboratory analysis of biopsy tissue or blood to look for new genetic changes that appeared after your first test. The results inform which next-line options are most suitable.
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.
Get a straight answer from a specialist
45 minutes, your reports reviewed, your questions answered in plain language.
What can a rebiopsy actually tell your oncologist?
A rebiopsy gives your oncologist two things: confirmation that the progression is real, and information about which biological pathway the cancer is now using to survive.
For some cancer types, a specific resistance mutation identifies a next-line option that directly targets it. For others, the result narrows the field — ruling out treatments unlikely to help and pointing toward those that are. Either way, it moves the conversation from a standard sequence to a directed choice.
If the rebiopsy site is difficult or risky to reach, a liquid biopsy is the most common alternative. Your oncologist will tell you whether a blood-based test is a validated option for your cancer type, or whether tissue is necessary.
What happens if a rebiopsy is not possible or gives no clear answer?
Not all tumours are safely accessible. A lesion in the lung, liver, or lymph node is usually reachable. One close to a major blood vessel or in the brain may not be safe to approach. If tissue cannot be obtained safely, liquid biopsy is the most common next step.
Sometimes neither test yields enough material to interpret, or the result does not reveal a new actionable change. In that situation, your oncologist uses your original pathology, your treatment history, and published evidence to recommend the next-line option. This is still a structured decision, not a guess.
NCCN and ESMO guidance for most solid tumours includes standard next-line options that do not depend on a rebiopsy result. Not being able to re-test does not mean running out of options.
Did you know?
A tumour at progression can be molecularly different from the same tumour at diagnosis — in some cancer types, the resistance mechanism that develops is entirely distinct from the original genetic change that drove the cancer.
This is why ASCO and ESMO recommend molecular re-testing at progression for several tumour types: the clinical decision being made concerns a different cancer than the one originally diagnosed.
Source: ASCO and ESMO guidelines on molecular testing at disease progression
Explore 39 more Monitoring, Resistance & Long-Term Response topics
Resistance, Progression & Next Lines
- Being Told 'There Are No More Options': Is That Really True?
- Brain Metastases on Targeted Therapy: Does Your Drug Reach the Brain?
- Can You Continue the Same Drug After Progression?
- Combination Therapy to Overcome Resistance
- Do You Need Another Biopsy When the Cancer Progresses?
- Histologic Transformation: When Lung Cancer Changes Type
- How to Emotionally Process a Progression Scan
- Leptomeningeal Disease: Symptoms, Diagnosis and Treatment
- Life After ALK Inhibitor Resistance: Sequencing Your Options
- MET Amplification and Other Bypass Resistance Mechanisms
- Oligoprogression: When Only One or Two Spots Grow
- Primary vs Acquired Resistance: Two Very Different Problems
- Should You Change Hospitals After Progression?
- What Happens After Osimertinib Stops Working?
- What Is Sequencing and Why the Order of Drugs Matters
- Why Does Targeted Therapy Stop Working? The Biology of Resistance
Long-Term Response, Stopping & Survivorship
- Am I Still a Cancer Patient? Identity After Long-Term Response
- Bone Health, Heart Health and Late Effects to Monitor
- Can You Ever Stop Targeted Therapy If the Cancer Is Gone?
- Drug Holidays: Are Planned Breaks Safe?
- Follow-Up Schedule After Stopping Targeted Therapy
- How Long Do You Have to Stay on Targeted Therapy?
- Long-Term Effects of Taking a TKI for 5 or 10 Years
- Restarting Treatment After a Break
- Treatment-Free Remission in CML: Who Can Stop Their TKI?
- Your Survivorship Care Plan: What Should Be In It
Monitoring, Scans & Response Assessment
- Are Tumour Markers Reliable on Targeted Therapy?
- Complete Response, Partial Response, Stable Disease: What Each Means
- Do I Need Regular Brain MRIs on Targeted Therapy?
- How Doctors Measure Whether Targeted Therapy Is Working
- How Often Will I Need Scans on Targeted Therapy?
- How to Read a CT or PET Scan Report Without Panicking
- Is 'Stable Disease' Good News or Bad News?
- Scanxiety: How to Get Through the Wait for Scan Results
- Tumour Flare and Pseudoprogression: When Growth Isn't Really Growth
- Understanding PFS, OS and Median Survival Without Losing Hope
- What Happens at a Follow-Up Visit: A Walk-Through
- Which Blood Tests Are Repeated Every Month and Why
- ctDNA Monitoring: Can a Blood Test Predict Progression Early?
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
Is a rebiopsy painful or risky?
The level of discomfort and risk depends entirely on where the biopsy is taken from. A biopsy of an accessible lymph node or a lesion just under the skin is a minor procedure done with local anaesthetic. A biopsy of a deep lesion in the lung or liver is more involved and carries a small risk of bleeding or other complications. Your oncologist will explain the specific risks for your situation before asking you to consent. If a liquid biopsy is a validated alternative for your cancer type, they will usually discuss that option first.
Can I refuse a rebiopsy?
Yes. No procedure can be done without your consent. If you decline, your oncologist will use your existing pathology and treatment history to recommend next-line treatment. It is worth asking what information a rebiopsy would add before deciding — in some cases it changes the treatment direction significantly, and in others the standard next-line option would be the same regardless. Understanding what is at stake helps you make an informed choice.
Is a liquid biopsy as accurate as a tissue biopsy?
For some resistance mutations in some cancer types, liquid biopsy is now a validated and guideline-endorsed alternative to tissue biopsy. For others, it detects resistance changes less reliably, particularly when the tumour sheds only small amounts of DNA into the blood. Your oncologist will know whether a blood-based test is an accepted substitute for your specific situation, or whether tissue remains necessary. When both are available, tissue is generally more informative — but the least invasive option that answers the clinical question is usually preferred.
How long will it take to get rebiopsy results?
Basic pathology from a rebiopsy — confirming what type of tissue was sampled — usually comes back within a few days. Molecular testing, which looks for specific resistance mutations, typically takes one to two weeks once the laboratory receives the sample. If the sample needs to go to a specialist molecular laboratory, it can take longer. Ask your oncologist when the sample was sent and what the expected turnaround is, so you have a timeline rather than open-ended waiting.
What if the rebiopsy shows no targetable mutation?
This is a common result, and it does not mean there is no next-line treatment available. Most cancer types have standard next-line options that are not contingent on finding a specific mutation. What it means is that the decision will be based on your cancer type, stage, treatment history, and general fitness rather than on a molecular target. Ask your oncologist which options remain available and what each is expected to achieve in your situation.
Does progression always mean the cancer can no longer be controlled?
No. Progression means the current treatment plan is no longer working — it does not mean the cancer cannot respond to a different approach. Many people go through multiple lines of treatment over time, with periods of control between progressions. What matters is which options remain and how your oncologist weighs the likelihood of response to each. Asking what the next treatment is aiming to achieve, and over what timeframe, is a reasonable and important question at this point.