Synopsis
Explain checkpoint blockade and tumour selection, obtain a safe multisystem baseline, distinguish immune toxicity from infection or progression, and coordinate prompt treatment without masking endocrine emergencies.
- PD-1, PD-L1 and CTLA-4 pathways restrain T-cell activation; checkpoint inhibitors release that restraint and can produce durable tumour control in selected cancers.
- Eligibility depends on tumour type, stage, treatment line and sometimes PD-L1, mismatch-repair or other biomarkers under the current protocol.
- Immune-related adverse events can affect any organ, appear after one dose or months after stopping, and involve several systems simultaneously.
- The initial action for suspected clinically important immune toxicity is to hold checkpoint treatment, grade severity and investigate immune, infective, malignant and medicine causes together.
- Corticosteroids are first-line treatment for many significant immune toxicities, but dose, route and taper depend on organ and severity; endocrine hormone loss often needs replacement rather than recovery.
- Myocarditis, myositis and myasthenic features can overlap and deteriorate rapidly despite modest early symptoms.
- Before giving thyroid hormone for possible hypophysitis, assess and protect the cortisol axis because unrecognised ACTH deficiency can precipitate crisis.
- Provide a treatment alert card and 24-hour contact, and tell every acute service about previous checkpoint exposure even after therapy ends.
Key red flags
Ptosis, dysphagia, proximal weakness, myalgia, chest pain or troponin elevation can combine myositis, myasthenia and myocarditis.
Investigation priorities
Establish marrow, renal, hepatic, glucose and electrolyte status before therapy.
Management branches
A patient is due to start checkpoint blockade.
- Confirm tumour indication, biomarker where required, autoimmune and transplant history, organ baseline and interacting immunosuppression.
- Explain organ-specific warning symptoms, delayed events, alert-card use and the 24-hour acute-oncology route.
- Record baseline bowel, respiratory, neurological, endocrine, skin and musculoskeletal status to make later change interpretable.
Key medicines
Pembrolizumab200 mg intravenously every 3 weeks or 400 mg every 6 weeks, infused over 30 minutes, for a licensed and funded indication. Do not reduce the dose; hold or discontinue according to organ toxicity, severity and the product and treatment protocol.Immune toxicity can affect any organ during or after treatment. Establish baseline function, give lifelong alert advice, assess infection and progression in parallel, and protect cortisol before starting thyroid replacement when adrenal or pituitary failure is possible.