FRCR VAULT

Lower GI: Anal cancer salvage and response assessment

Free question published 16 September 2026

Lower GIAnal cancer salvage and response assessment

A 59-year-old man treated with definitive mitomycin and 5-fluorouracil chemoradiotherapy for a T2 N0 anal squamous cell carcinoma is reviewed in clinic. At the planned assessment there is a persistent firm nodule at the primary site, and biopsy at 26 weeks confirms residual viable squamous carcinoma without distant metastases. What is the most appropriate management?

  1. ASalvage abdominoperineal resection
  2. BPalliative best supportive care only
  3. CContinued surveillance, as response can occur up to one year after chemoradiotherapy
  4. DMaintenance cisplatin and 5-fluorouracil chemotherapy
  5. EA further course of the same chemoradiotherapy to the same dose

Why A is correct

Definitive chemoradiotherapy with mitomycin and 5-fluorouracil is the organ-preserving standard of care for anal squamous cell carcinoma, with surgery reserved for failure. Biopsy-proven persistent disease at 26 weeks represents local failure, and salvage abdominoperineal resection is the mainstay of treatment for locoregional failure after chemoradiation.

And why the others are not

  • BIncorrect. With localised, non-metastatic persistent disease, curative-intent salvage surgery is appropriate rather than best supportive care alone.
  • CIncorrect. Although some responses occur late, biopsy-confirmed persistent viable tumour at 26 weeks is local failure requiring salvage surgery, not further watching.
  • DIncorrect. Maintenance chemotherapy was shown ineffective in ACT II and does not treat established residual disease.
  • EIncorrect. Re-irradiation to full dose is not standard for persistent disease and carries prohibitive toxicity; surgery is indicated.

Source Salvage abdominoperineal resection after chemoradiation for anal squamous cell carcinoma — Oncologic Outcomes of Salvage Abdominoperineal Resection for Anal Squamous Cell Carcinoma Initially Managed with Chemoradiation. J Clin Med. 2024 (PMC11050212).

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