Chemoradiotherapy with Brachytherapy or Electron Therapy Boost for Locally Advanced Squamous Cell Carcinoma of the Anus-Reducing the Colostomy Rate.

Purpose: The aim of this study is to determine overall survival, disease-specific survival and stoma-free survival after treatment of squamous cell carcinoma of the anus with chemoradiotherapy followed by brachytherapy or electron boost in a recent cohort of patients.

Methods: Fifty-two patients (median age 62 years) were treated with radical chemoradiotherapy (mitomycin C, infusional 5-fluorouracil concurrently with conformal radical radiotherapy 45 Gy in 25 fractions over 5 weeks) followed by a radiotherapy boost between 1 December 2000 and 30 April 2011. Follow-up was to 30 November 2014. Thirty-six patients received a boost (15-20 Gy) over 2 days with Ir needle brachytherapy for anal canal tumours, and 16 patients received electron beam therapy (20 Gy in 10 fractions in 2 weeks) for anal margin tumours. A defunctioning stoma was only created prior to chemoradiotherapy for fistula or severe anal pain.

Results: The overall survival for the 36 patients treated with chemoradiotherapy followed by brachytherapy was 75 % (95 % CI, 61-89) at 5 years, the disease-specific survival was 91 % (95 % CI, 81-101 %), and the stoma-free survival was 97 % (95 % CI, 91-103 %) all at 5 years. For the 16 patients treated with an electron boost for anal margin tumours, the 5-year overall survival, disease-specific survival and stoma-free survival were 68 % (95 % CI, 44-92 %), 78 % (95 % CI, 56-100 %) and 80 % (95 % CI, 60-100 %), respectively.

Conclusions: A very low stoma formation rate can be obtained with radical chemoradiotherapy followed by a brachytherapy boost for squamous cell carcinoma of the anal canal but not with an electron boost for anal margin tumours.