Immunotherapy

What immunotherapy is — in plain words

Cancer cells often hide from the immune system by pressing a kind of "off switch" on the immune cells that should be hunting them. Checkpoint inhibitor drugs — pembrolizumab, nivolumab, atezolizumab, durvalumab, ipilimumab, and others — block that off switch. The result is that your own T-cells can suddenly see the cancer again and attack it. The medicine itself does not kill cancer; your immune system does.

This is a fundamentally different approach from chemotherapy. Chemotherapy works on the cancer; immunotherapy works on you. That difference shapes everything about how it's given, how long it works, and the side effects it can cause.

"The first time a patient on immunotherapy comes back for a scan and the tumour has shrunk, I always remind them: the drug didn't do that. Your own body did. We just gave it permission."

Which cancers respond to immunotherapy

Immunotherapy is now part of standard care — sometimes as first-line treatment, sometimes after chemotherapy — for a growing list of cancers. The most established uses include:

• Lung cancer (non-small cell and small cell) — often combined with chemotherapy or given alone if PD-L1 expression is high.
• Melanoma — the cancer where immunotherapy first transformed survival, and still its strongest indication.
• Kidney cancer — usually in combination with another immunotherapy or a targeted drug.
• Bladder and other urinary tract cancers — both for advanced disease and after surgery in selected cases.
• Head and neck cancers, liver cancer, stomach and oesophageal cancers, cervical cancer, triple-negative breast cancer, Hodgkin lymphoma — all have established roles.
• Any tumour with MSI-high or high tumour mutational burden — regardless of where it started, these molecular features predict response.

Before recommending immunotherapy, we usually test the tumour for PD-L1 expression and, where relevant, microsatellite instability. These tests help predict who is most likely to benefit.

What an infusion day looks like

1. You arrive at the clinic. A nurse checks your weight, blood pressure, oxygen level, and reviews your blood work — especially thyroid, liver, and kidney function.
2. We ask about any new symptoms since your last visit — even minor ones like a new rash, looser stools, a dry cough, or unusual tiredness. These small details matter.
3. The drug is mixed in the pharmacy and given through a drip over 30 to 60 minutes. No pre-medications are usually needed.
4. You're observed for a short period afterwards, then you go home. Most patients feel completely normal and drive themselves home or back to work.
5. Treatment is given every 2, 3, 4, or 6 weeks depending on the drug and dose schedule. Many patients continue for up to two years if it's working.

Immune-related side effects — what makes immunotherapy different

Because immunotherapy revs up the immune system, that immune system can occasionally attack healthy organs as well as the tumour. These are called immune-related adverse events. Most are mild. A few can be serious if missed. The pattern matters more than the symptom itself — anything new during immunotherapy deserves a phone call.

Less commonly, immunotherapy can affect the liver (raised enzymes on blood tests), the joints (a kind of inflammatory arthritis), the kidneys, the heart, or the nervous system. The chance of any one of these is small. The chance of some immune-related event over a course of treatment is real — which is why monitoring is built into every visit.

How we know if it's working — and the puzzle of pseudoprogression

The first scan after starting immunotherapy is usually done at 9 to 12 weeks. Most of the time, the news is straightforward: the tumour has shrunk, stayed the same, or grown.

Occasionally, something strange happens — the tumour appears larger on the first scan, but the patient feels well, with no new symptoms. This can be "pseudoprogression": immune cells flooding into the tumour, making it look bigger before it shrinks. If your clinical picture is good, we may repeat the scan in 4 to 6 weeks before changing course. The opposite pattern — feeling worse with a stable scan — also matters, and we take it seriously.

When immunotherapy works, it often works for a long time. A subset of patients who respond well continue to do well years after stopping the drug — the immune memory persists. This long tail of durable response is what makes immunotherapy a genuinely different kind of cancer treatment.

What immunotherapy is not

• Not for everyone. Some cancers don't respond, and we won't recommend it when the evidence isn't there.
• Not gentle for every patient. Most tolerate it very well — but the people who get a severe immune reaction can be very sick. Honest monitoring is essential.
• Not always combined with chemotherapy. Sometimes it replaces chemotherapy; sometimes it's added to it; sometimes it follows it. The combination depends on the cancer.
• Not a cure-all. When it works, it can work spectacularly. When it doesn't, we move on to other options without hesitation.

Special situations to discuss honestly

If you have an autoimmune condition (rheumatoid arthritis, lupus, inflammatory bowel disease, psoriasis, autoimmune thyroid disease), immunotherapy can sometimes flare it. That doesn't always rule the treatment out — but it's a conversation we'll have carefully, weighing the benefit against the risk. The same applies if you've had an organ transplant or are on long-term steroids for another condition.

Cost, access, and planning ahead

Immunotherapy drugs are expensive, and access varies. We'll discuss the financial picture openly — including whether insurance covers a given drug, whether a patient assistance programme is available, and whether a clinically equivalent alternative exists. No one should be choosing a treatment without understanding what it will cost their family.

Working, family life, and travel

Most patients on immunotherapy continue to work and live normally between infusions. There's no neutropenic period to plan around, no expected hair loss, and infusions are short. The main thing to plan for is the monitoring: blood tests before each cycle, scans every 9 to 12 weeks, and a low threshold for calling in. Learn about long-term follow-up →