Side effects of immunotherapy for lung cancer

Immunotherapy helps the immune system recognise and attack cancer, but the immune response can sometimes irritate healthy tissue. Effects may start during treatment or after an infusion course has ended. They can be mild at first and then become more serious, so a new or changing symptom deserves attention.

Possible changes include an itchy or widespread rash, diarrhoea, abdominal pain, a new cough, breathlessness, yellowing of the eyes or skin, dark urine, unusual tiredness, headaches, dizziness, or changes in thirst and urination. These symptoms can have causes unrelated to treatment, but the oncology team needs to assess them.

Keep the treatment team's contact details available and tell them about symptoms early, including when they began, how they are changing, and whether they affect eating, drinking, sleep, or normal activity. Bring a current list of medicines and supplements to appointments.

Do not start steroids, anti-diarrhoea medicines, or other treatments for a suspected immune reaction without guidance. Your team may advise an examination, blood tests, scans, or a pause in treatment. Follow the plan they give you and attend monitoring visits even when you feel well.

Contact your cancer team promptly for new or worsening breathlessness, chest pain, persistent cough, repeated diarrhoea, blood in stool, severe abdominal pain, confusion, fainting, marked weakness, or inability to keep fluids down. Seek emergency help for severe breathing difficulty, sudden collapse, or signs of a severe allergic reaction such as swelling of the face or throat.

Ask which symptoms should be reported immediately, whom to call outside clinic hours, and whether your current medicines could hide or worsen a treatment reaction. You can also ask how symptoms will be monitored, when treatment might be delayed, and what information to record between visits.