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BCG Cystitis — SCE Medical Oncology MCQ

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ModerateUrological CancersBCG CystitisSCE Medical Oncology

A 60-year-old man with non-muscle-invasive bladder cancer (NMIBC, high-grade Ta) is started on intravesical BCG induction. He develops severe cystitis (dysuria, frequency, haematuria) after the 4th instillation. Urine culture is negative. What is this?

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Correct answer: A — BCG cystitis — a local immune-mediated inflammatory response to BCG; managed by delaying the next instillation, analgesics (paracetamol, NSAIDs) and anticholinergics; rarely requires anti-tuberculosis therapy unless systemic BCG-osis develops

BCG cystitis is the most common local adverse effect of intravesical BCG (~80% of patients), reflecting the desired local immune response. Management: delay next instillation until symptoms resolve, symptomatic treatment (analgesics, anticholinergics, phenazopyridine). Dose reduction (1/3 or 1/10 dose) may be needed for subsequent instillations. Systemic BCG-osis (fever >38.5°C for >48h, hepatitis, pneumonitis, sepsis) is rare (~1%) but requires anti-tuberculosis therapy (isoniazid, rifampicin, ethambutol) and is a medical emergency.

Reference: ESMO 2024 Bladder Cancer; EAU NMIBC Guidelines; BNF BCG