Role of brachytherapy in the treatment of cancers of the anal canal Long-term follow-up and multivariate analysis of a large monocentric retrospective series

Background and Purpose. There are few data on long-term clinical results and tolerance of brachytherapy in anal canal cancer. We present one of the largest retrospective analyses of anal canal cancers treated with external beam radiotherapy with/without (+/-) chemotherapy followed by a brachytherapy boost. Materials and Methods. We performed a retrospective analysis of clinical results in terms of efficacy and toxicity. The impact of different clinical and therapeutic variables on these outcomes was studied. Results. From May 1992 to December 2009, 209 patients received brachytherapy after external beam radiotherapy +/- chemotherapy. Of these patients, 163 were stage II or stage IIIA (UICC 2002) and 58 were N1-3. According to age, ECOG performance status (PS), and comorbidities, patients received either radiotherapy alone (58/209) or radiochemotherapy (151/209). The median follow-up was 72.8 months. The 5- and 10-year local control rates were 78.6 and 73.9 %, respectively. Globally, severe acute and late G3-4 reactions (NCI-CTC scale v. 4.0) occurred in 11.2 and 6.3 % of patients, respectively. Univariate analysis showed the statistical impact of the pelvic treatment volume (p = 0.046) and of the total dose (p = 0.02) on the risk of severe acute and late toxicities, respectively. Only six patients required permanent colostomy because of severe late anorectal toxicities. Conclusion. After a long follow-up time, brachytherapy showed an acceptable toxicity profile and high local control rates in patients with anal canal cancer.