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Lower GI: Anal cancer definitive chemoradiotherapy

Free question published 05 September 2026

Lower GIAnal cancer definitive chemoradiotherapy

A 62-year-old woman presents with a 4 cm squamous cell carcinoma of the anal canal with one suspicious mesorectal node and no distant metastases. She is keen to preserve sphincter function. Which first-line definitive treatment should be recommended?

  1. AUpfront abdominoperineal resection
  2. BConcurrent chemoradiotherapy with cisplatin and 5-fluorouracil, as cisplatin gives a higher complete response rate
  3. CConcurrent chemoradiotherapy with mitomycin and 5-fluorouracil
  4. DChemoradiotherapy followed by maintenance cisplatin and 5-fluorouracil
  5. ERadiotherapy alone without concurrent chemotherapy

Why C is correct

ACT II established that fluorouracil and mitomycin with 50.4 Gy radiotherapy in 28 fractions should remain standard practice in the UK for anal squamous cell carcinoma. Cisplatin was not superior to mitomycin for complete response (90.5% vs 89.6%, p=0.64) and maintenance chemotherapy gave no progression-free survival benefit.

And why the others are not

  • AIncorrect. Surgery is reserved for salvage of persistent or recurrent disease; chemoradiotherapy preserves the sphincter as first-line treatment.
  • BIncorrect. Cisplatin was not superior to mitomycin for complete response (90.5% vs 89.6%, p=0.64).
  • DIncorrect. ACT II showed maintenance chemotherapy gave no improvement in progression-free survival (74% vs 73%, p=0.70).
  • EIncorrect. Concurrent chemotherapy improves outcomes over radiotherapy alone and is standard for localised anal cancer.

Source ACT II trial — chemoradiotherapy for squamous-cell carcinoma of the anus — James RD, Glynne-Jones R, Meadows HM, et al. Mitomycin or cisplatin chemoradiation with or without maintenance chemotherapy for treatment of squamous-cell carcinoma of the anus (ACT II): a randomised, phase 3, open-label, 2 x 2 factorial trial. Lancet Oncol. 2013.

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