When to worry about persistent fatigue with immunotherapy side effects

Immunotherapy can activate the immune system against healthy tissues as well as cancer cells. Fatigue may accompany inflammation affecting hormone-producing glands, lungs, liver, bowel, skin, or other organs. The timing can vary, and symptoms may appear during treatment or after an infusion. Fatigue alone cannot show which organ is involved, so the pattern and accompanying symptoms matter.

Call your oncology team and explain when the fatigue began, whether it is progressing, and how it affects walking, eating, washing, work, or sleep. Mention every new symptom and medicine. Keep your treatment information available. Do not skip an infusion, take steroids, or use new supplements unless the treating team advises it; some immune-related problems need tests and specific treatment rather than extra rest.

Seek emergency help for severe breathlessness, chest pain, fainting, confusion, inability to stay awake, a seizure, sudden weakness, or inability to keep fluids down. Contact the cancer team urgently for fever, severe diarrhoea, black or bloody stools, a rapidly spreading rash, severe headache, or major changes in thirst and urination. Early reporting helps the team decide how quickly you need assessment.

Ask which symptoms could signal inflammation in a particular organ, which blood tests or scans may be needed, whether your treatment schedule should change, and whom to call outside clinic hours. Ask how to pace activity while the cause is being assessed.