Medical Oncologist
Drug Deep Dive: Gefitinib
Tests and Monitoring — While You Are on Gefitinib
Gefitinib requires regular blood tests and scans while you are taking it. Each test serves a specific purpose: checking that the drug is not harming your liver or lungs, and confirming that it is still working against the cancer.
Medically reviewed by Dr. Bharati Devi Gorantla, Medical Oncologist, MBBS · MD · DM (Adyar, Chennai) · ECMO · MRCP SCE (UK) · Last reviewed August 2026
- Liver tests come first — Blood tests checking your liver enzymes are the most frequent check in the early weeks, because gefitinib can raise those levels in a proportion of patients.
- Response scans confirm benefit — A CT scan, usually at six to eight weeks, shows whether the tumour is responding before you continue on the drug long-term.
- New breathlessness is always urgent — A rare but serious lung reaction means any new or worsening breathlessness needs same-day contact with your team, not a wait for your next appointment.
- Resistance testing if it stops working — If gefitinib eventually stops controlling the cancer, a blood test or biopsy can identify the mutation driving resistance and guide what comes next.
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On gefitinib, your team will check your liver enzymes every four to eight weeks initially — in line with NCCN and ESMO guidance — do a response CT scan at six to eight weeks, and monitor for lung and skin reactions throughout. Liver tests catch a common side effect early; response scans confirm the drug is still working.
How does monitoring work, from day one?
Baseline tests before your first dose
Before you start, your team records your liver enzymes, full blood count and kidney function. A baseline imaging result is also documented so later scans have something to compare against.
Liver blood tests in the first three months
NCCN and ESMO guidance recommends checking liver enzymes every four to eight weeks during the first three months, when the risk of liver-related changes is highest. These are simple blood draws, usually done at your review appointment.
First response scan at six to eight weeks
A CT scan of your chest is usually arranged six to eight weeks after starting. This is not a safety check — it is confirmation that the tumour is responding before you continue on the drug long-term.
Ongoing monitoring every two to three months
After the first response scan, scans typically continue every two to three months and blood tests continue periodically. The frequency may reduce if your results remain stable over time.
Resistance testing if the drug stops working
If scans eventually show the cancer growing again on gefitinib, a liquid biopsy or repeat tissue biopsy checks for resistance mutations, including T790M. The result guides which treatment is most likely to help next.
What to track between appointments
- Any new or worsening breathlessness, even if mild — report it the same day, not at your next appointment
- A dry cough that is new or getting worse
- Any skin rash, especially on your face and upper chest — note when it started and what it looks like
- Yellowing of your eyes or skin, or dark urine — these may suggest a liver reaction
- Diarrhoea — note how often it is happening and whether it is settling or worsening
- Sore or dry eyes — gefitinib can occasionally affect the eyelid lining
- Any new medicines, supplements or herbal remedies you start between appointments — some interact with gefitinib
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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)
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Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
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Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
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Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
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Radiation Oncologist
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Dr. Mohammed Imran
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Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
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What does each test check for, and what does a change mean?
| Test | Usual schedule | What a change may mean |
|---|---|---|
| Liver enzymes (ALT / AST) | Every 4–8 weeks for the first 3 months, then periodically | A rise usually causes no symptoms and is caught by routine testing. A significant increase may prompt a dose pause while levels settle. Most cases resolve without permanently stopping treatment. |
| Full blood count | Before starting, then periodically as needed | Serious blood count changes are uncommon with gefitinib. Your team checks for anaemia or other findings that might explain fatigue or other symptoms you report. |
| CT chest — response scan | Around 6–8 weeks after starting, then every 2–3 months | Shrinkage or stability means the drug is working. If the tumour grows while you are on gefitinib, resistance testing is the next step before changing treatment. |
| Chest imaging — symptom-triggered | Only if you develop new breathlessness, cough or fever | New changes on imaging alongside respiratory symptoms may indicate drug-related lung inflammation (ILD). Gefitinib is paused immediately while the cause is confirmed. |
| Skin review | At each clinic visit | Rash on the face and upper body is common and usually manageable. A severe or blistering rash needs prompt review to decide whether the dose needs to change. |
| Eye review | If you report eye symptoms | Conjunctivitis or persistent dry, sore eyes are occasionally reported. An eye specialist review may be arranged if symptoms do not settle. |
| Typically starts | Blood tests begin before your first dose; first response scan at 6–8 weeks | Baseline results are recorded before treatment begins so any later change can be measured against them. |
Why is new breathlessness always urgent on gefitinib?
Gefitinib can, in a small proportion of patients, cause inflammation of the lung tissue — a reaction called drug-related pneumonitis or interstitial lung disease (ILD). ESMO and NCCN guidance treats any new or worsening breathlessness on an EGFR inhibitor as needing same-day assessment.
ILD can look identical to a chest infection or a cancer-related change on first presentation. The difference matters because the treatments are opposite: ILD requires pausing gefitinib and sometimes starting steroids, while an infection requires antibiotics. A chest image is needed before either decision is made.
Do not wait for your next scheduled appointment if you notice new breathlessness, a dry cough that is getting worse, or fever alongside these symptoms. Contact your team the same day.
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Common questions
Frequently asked questions
How often will I need blood tests on gefitinib?
In the first three months, liver enzyme tests are typically done every four to eight weeks, in line with NCCN and ESMO guidance. After that, the frequency reduces if your results have been stable. Tests are usually coordinated with your regular review appointments rather than requiring a separate visit.
What happens if my liver enzymes go up?
A rise in liver enzymes on gefitinib is not uncommon and usually causes no symptoms — it is caught through routine blood testing. Your team may pause the dose while the levels settle, then restart at the same or a lower dose. Permanently stopping treatment for this reason alone is uncommon, particularly when the rise is mild and caught early.
Do I need a scan at every review appointment?
No. Scans are not done at every visit. The first response scan is typically at six to eight weeks, and ongoing scans are usually every two to three months. Blood tests are more frequent, especially early on. Between scans, your team relies on your blood results and how you feel to guide decisions about your dose.
What is the T790M test and when is it done?
T790M is a mutation that often develops in EGFR-positive tumours as they become resistant to gefitinib. It is tested when scans show the cancer is growing again on treatment — it is not part of routine monitoring while the drug is working. A positive result means a different EGFR inhibitor may still be effective, and the test can often be done from a blood sample rather than a repeat biopsy.
Can I have my blood tests done at a local laboratory instead of the cancer centre?
For straightforward tests like liver enzymes and full blood count, your oncologist may agree to have these done at a local facility, with results shared with the cancer centre before your review appointment. Ask your team at your next visit — it depends on whether your local laboratory can reliably transmit results and whether your team needs to examine you at the same appointment.