Immunotherapy

Immunotherapy is a cancer treatment that works by helping the patient's own immune system find and destroy cancer cells.

Normally, cancer cells can hide from the immune system by sending out signals that tell immune cells to leave them alone. Immunotherapy drugs block those hiding signals or give immune cells a stronger boost so they can recognise and attack the tumour. Unlike chemotherapy, which directly kills dividing cells throughout the body, immunotherapy targets the immune system's own machinery, so the effect can last long after the treatment course ends.

Immunotherapy is used for a wide range of cancers, especially those that have spread, come back after earlier treatment, or do not respond well to chemotherapy or radiation alone. The oncologist (cancer specialist) will check the tumour's biology before deciding whether immunotherapy is appropriate.

• Melanoma (skin cancer) — one of the first cancers where immunotherapy showed strong results
• Non-small cell lung cancer
• Bladder cancer
• Kidney cancer (renal cell carcinoma)
• Head and neck cancers
• Colorectal (bowel) cancer with certain genetic markers
• Liver cancer (hepatocellular carcinoma)
• Cervical cancer
• Lymphoma (cancer of the lymphatic system)
• Some types of breast cancer
• Certain solid tumours that have a specific marker called MSI-H or dMMR, regardless of where in the body they started

Immunotherapy is not suitable for everyone. A doctor may advise against it in certain situations, including:

• Active autoimmune disease (a condition where the immune system already attacks the body's own tissue), because immunotherapy can make it worse
• Patients who have recently had an organ transplant, as the treatment can trigger rejection
• Tumours whose biology tests show they are unlikely to respond to immune-based treatment
• Severe damage to organs such as the lungs, hati (liver), or kidneys that could not safely tolerate the treatment's side effects

Because immunotherapy stimulates the immune system, the most significant risks come from that same immune system becoming overactive and attacking healthy tissues — a pattern doctors call immune-related adverse events (irAEs).

• Fatigue and general tiredness — the most commonly reported side effect
• Skin rash or itching
• Diarrhoea or colitis (inflammation of the bowel lining)
• Pneumonitis (inflammation of the lung tissue), causing cough or shortness of breath
• Hepatitis (liver inflammation), detected by blood tests even before symptoms appear
• Endocrine (hormonal gland) problems — the thyroid, pituitary, or adrenal glands may become underactive or overactive
• Joint pain or muscle aches
• Infusion reactions — fever, chills, or low blood pressure during the drip, more common with the first dose
• Nephritis (kidney inflammation), which can affect kidney function
• In rare cases, severe inflammation of the heart muscle (myocarditis) or nervous system
• Most irAEs are manageable and reversible when caught early; your care team will monitor for them at every visit

Preparation for immunotherapy begins weeks before the first infusion (drip session). The medical team needs a full picture of your health because any hidden autoimmune condition, infection, or organ problem can affect how safely you receive the treatment.

Before the first session, the following tests are usually ordered:

• Blood tests to check liver function, kidney function, thyroid hormone levels, and blood cell counts
• Imaging — CT or MRI scans — to document the size and location of the tumour before treatment begins, so progress can be measured
• Biomarker (biological marker) tests on tumour tissue: for example, PD-L1 expression (a protein on the tumour surface that predicts response) and MSI or TMB (tumour mutation burden — a measure of how many genetic changes the tumour carries)
• Lung function test if pneumonitis risk is a concern
• Heart trace (ECG) in some hospitals
• A full medication review — some supplements, herbal products, and corticosteroids (anti-inflammatory drugs) can affect the immune system and may need to be paused

On the day of each infusion session, the following steps usually happen in this order:

• 1. Check-in and vital signs: blood pressure, temperature, heart rate, and weight are recorded.
• 2. Blood draw: a fresh blood sample is taken to check liver, kidney, and thyroid results before proceeding.
• 3. The doctor or nurse reviews the results and confirms it is safe to continue.
• 4. A cannula (small plastic tube) is inserted into a vein, usually in the arm.
• 5. Pre-medications such as antihistamines or anti-nausea drugs may be given through the cannula to reduce infusion reactions.
• 6. The immunotherapy drug is given slowly as an intravenous (IV) infusion over a period set by your care team — usually ranging from 30 minutes to several hours depending on the specific drug and dose.
• 7. The nurse monitors for any infusion reaction throughout the session.
• 8. After the infusion finishes, you are observed for a further period before leaving.

There is usually no requirement to fast before an immunotherapy infusion, but your care team will give you specific instructions. If you smoke or drink alcohol regularly, the team may advise reducing or stopping, as these can affect immune function and overall treatment tolerance.

Most patients go home the same day as each infusion session. Because immunotherapy is given in cycles — typically every two, three, or four weeks over many months — aftercare is an ongoing process, not a single recovery period. The priority after each session is watching for delayed immune reactions, which can appear days or even weeks after the infusion.

• Monitoring: blood tests to check liver, kidney, thyroid, and hormone levels are repeated before each new cycle and whenever new symptoms appear
• Symptom reporting: patients are usually given a list of warning signs — such as new cough, shortness of breath, severe diarrhoea, yellow skin (jaundice), unusual tiredness, or visual changes — and told to contact their care team promptly if any occur
• Activity: most patients can continue light daily activities between sessions; strenuous exercise or activities that risk infection should be discussed with the care team
• Diet and nutrition: no single diet is required, but the team may refer patients to a dietitian (nutrition specialist) if weight loss or appetite problems develop
• Alcohol and smoking: reducing or avoiding both is generally advised during treatment, as they can stress the liver and lungs — organs already monitored for inflammation
• Other medications: any new drug, supplement, or herbal product should be checked with the oncologist before starting, as some can interfere with immunotherapy or mask its side effects
• Vaccinations: live vaccines (such as yellow fever) are usually avoided during treatment; the care team will advise on timing for any needed vaccines
• Psychological support: long treatment courses can be emotionally demanding; asking the care team about counselling or support groups is encouraged
• Follow-up imaging: CT or MRI scans are repeated at intervals set by the oncologist to assess how the tumour is responding
• Long-term follow-up: some immune-related side effects, particularly hormonal ones, can persist after treatment ends and may need ongoing management