Medical Oncologist
Gefitinib timeline
How Long Does Gefitinib — Take to Work?
Gefitinib starts blocking the signal your cancer cells depend on from the first dose. Symptom relief can come before a scan confirms it — but the scan, usually at around six to eight weeks, is when you get your first clear answer.
Medically reviewed by Dr. T. Raghavender Reddy, Medical Oncologist, MBBS · DM (Medical Oncology) · MD (Radiation Oncology) · Last reviewed August 2026
- Symptom relief can come first — Some people feel better before imaging shows any change.
- The first scan is the real marker — Most oncologists schedule it at around six to eight weeks.
- No change does not mean failure — Stable disease — no growth — is also a meaningful result.
- Take it at the same time each day — Consistency matters more than the specific hour you choose.
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Gefitinib begins working on cancer cells from the first dose. Symptom relief — less coughing, easier breathing — can appear within the first one to two weeks for some people. Tumour response is confirmed on your first CT scan, which most oncologists schedule at around six to eight weeks.
Do you feel anything in the first week?
Most people notice very little in the first few days. Targeted therapies like gefitinib work quietly — they are not like chemotherapy, where the effect on the body is often immediate and unmistakable.
Some people develop mild fatigue or loose stools in the first week. These usually settle as your body adjusts to the medicine.
A skin rash — often on the face, neck, or chest — may appear in the first one to two weeks. Tell your team when it does. It is often a signal that the drug is active, not a sign that something has gone wrong.
What should you watch for while taking gefitinib?
- Note whether your main symptom — breathlessness, cough, or pain — has changed since starting
- Tell your team if a rash appears on your face or body, even if it seems mild
- Record whether you feel more able to do daily activities than the week before
- Keep taking the tablet at the same time each day, even on days when you feel well
- Write down any new symptoms rather than waiting until your next appointment to mention them
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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
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What happens week by week?
Days 1 to 7 — Starting
You take one tablet each morning. Most people notice little visible change. Mild fatigue or loose stools may appear and usually settle within the week.
Weeks 1 to 2 — First possible symptom shifts
Some people notice their main symptom — breathlessness, cough, or pain — beginning to ease. If a skin rash appears, tell your team. It is a signal worth reporting, not ignoring.
Weeks 3 to 5 — Continuing treatment
If symptoms have improved, that usually continues. If you have not noticed much difference yet, that does not mean the drug is not working — imaging is the only reliable measure of tumour response.
Weeks 6 to 8 — First response scan
Your oncologist schedules a CT scan, usually at around six to eight weeks. This is the first objective measure of whether the tumour has responded to the drug.
After the scan — Acting on what it shows
If the scan shows the tumour is stable or smaller, treatment continues. If the cancer has grown, your oncologist will discuss the next options with you. Either way, you now have information to move forward on.
What will the scan actually show?
Your oncologist will look for whether the tumour has shrunk, stayed the same, or grown. Shrinkage — even partial — is a positive response. Stable disease, where the cancer has not grown meaningfully, is also a useful result.
A complete response, where no cancer is visible on imaging, is less common but does happen. The term your report may use is RECIST response — ask your team to explain what the specific finding means for your next step.
A good result at the first scan is not permanent. Scans continue throughout treatment to check that the response is being maintained.
Did you know?
In patients whose tumours carry an EGFR mutation, gefitinib often produces symptom relief before the first response scan can confirm it — because the drug begins blocking the cancer's growth signal from the first dose.
This is one reason NCCN and ESMO both list EGFR tyrosine kinase inhibitors as the preferred first-line treatment for EGFR-mutated non-small cell lung cancer.
Source: NCCN Guidelines for Non-Small Cell Lung Cancer; ESMO Clinical Practice Guidelines for Metastatic NSCLC
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Common questions
Frequently asked questions
How will I know if gefitinib is actually working?
The clearest answer comes from your CT scan at around six to eight weeks. Before that, improving symptoms — less coughing, better breathing, more energy — are encouraging signs but not proof. The scan is the first objective measure. Ask your oncologist to explain exactly what the report shows and what it means for your treatment plan going forward.
What if I feel no different after two weeks?
That does not mean the drug is not working. Some patients have no noticeable symptom change but show clear tumour shrinkage on their first scan. Gefitinib works at the molecular level, and that does not always produce a feeling you can identify. Continue the tablet as prescribed and wait for the scan before drawing conclusions.
Can the skin rash tell me whether gefitinib is working?
The rash is a pharmacological signal — it means the drug is having an effect on EGFR-expressing cells in the skin, which uses the same pathway as EGFR-mutated tumours. Some oncologists regard it as reassuring, though it is not a reliable predictor of tumour response in any individual. Tell your team when it appears and ask whether it needs treatment or monitoring. Do not stop the tablet because of a rash without guidance.
What happens if the first scan shows no response?
Your oncologist will review the scan alongside your symptoms and overall condition. If the cancer has grown, a change in treatment will be discussed. This may include a different targeted therapy or another approach, depending on what molecular testing shows at that point. A poor result at the first scan is information, not the end of treatment options.
How long do people stay on gefitinib if it is working?
Treatment continues as long as the drug is controlling the cancer and the side effects are manageable. There is no fixed maximum duration set in advance. Most oncologists scan every two to three months to check whether the response is maintained. If the disease starts to grow again — which can happen after months or years — a change in treatment will be considered.
Can gefitinib stop working even if it worked at first?
Yes. Most tumours eventually develop resistance to gefitinib. This is an expected part of how targeted therapies behave over time, not a personal treatment failure. When resistance develops, your oncologist will likely recommend repeat testing — including a biopsy or liquid biopsy — to understand what has changed and which treatment to try next. Knowing this in advance means a change in your scan result is not a surprise.