Can immunotherapy cause immunotherapy side effects?

The type and timing vary between people and treatments. A reaction may begin during treatment or after it has ended, so new symptoms should still be linked to your immunotherapy history when you speak with a clinician.

Some immunotherapies remove brakes from immune cells so they can attack cancer. The same response may cause inflammation elsewhere. Skin, bowel, lungs, liver, kidneys, hormone-producing glands, joints, nerves, eyes and the heart can be affected. Symptoms may seem unrelated, while liver, kidney or hormone changes may first appear on blood tests.

A rash, persistent diarrhoea, abdominal pain, new cough, breathlessness, unusual fatigue, headache, vision changes, muscle weakness or changes in thirst and urination all deserve attention. These symptoms have many possible causes, so the cancer team needs to assess them rather than assuming they are immune-related.

Follow the reporting plan provided by your treatment centre and contact the oncology team early when a symptom is new, persistent or worsening. Tell any clinician who treats you the exact immunotherapy medicine and when you last received it. Keep the team's contact details and your treatment information accessible.

Do not self-treat persistent diarrhoea, breathlessness or a spreading rash without advice, and do not start steroids on your own. Management depends on the affected organ and severity; the team may arrange examinations and tests, pause treatment, or prescribe medicine to calm the immune response.

Call your oncology service urgently for worsening diarrhoea, blood or black colour in the stool, yellow skin or eyes, reduced urine, a new severe headache, marked weakness, eye pain or vision change. Seek emergency care for severe trouble breathing, chest pain, fainting, confusion, a seizure, rapidly spreading blistering skin or swelling of the face or throat. State immediately that you receive or previously received immunotherapy.

Ask which immune-related effects are associated with your medicine, whom to call outside clinic hours, and which symptoms require emergency care. Discuss any autoimmune disease, transplant, lung condition or hormone disorder before treatment. Also ask what monitoring is planned and how a treatment pause would affect the cancer plan.