Purpose: A retrospective analysis of conservative treatment of anal canal cancers with external radiation therapy and interstitial brachytherapy with or without chemotherapy.
Patients and methods: From 1986 to 1996, 69 patients were treated with external radiotherapy (40 Gy/20 fractions) and interstitial brachytherapy (20 Gy) after a mean interval of six weeks for a localized epidermoid carcinoma of the anal canal. Patients who did not complete the whole therapeutic sequence were not included. Forty-five patients received additional 5-fluorouracil- and/or mitomycin C-based chemotherapy regimen.
Results: Acute toxicity was acceptable. Complete response rate was 81%. Actuarial local control rate was at two and five years, 65% and 59% respectively (median follow-up: eight years). At two, five and ten years, actuarial colostomy rate was 26%, 33% and 33% respectively, and colostomy-free survival rates 61%, 47% and 37%. Overall survival at two, five and ten years was 81%, 65% and 53% respectively. Distant metastases occurred in 11 patients (16%). Prognostic factors for overall survival were performance status (PS) (79% survival at five years for patients with PS 0 versus 50% for patients with PS 1-3, P = 0.04) and tumor stage (80% at five years for T1-T2 versus 53% for T3-T4, P = 0.03). Overall treatment time less than 12 weeks and time interval between external radiotherapy and brachytherapy inferior than six weeks were associated with a better local control (P = 0.05). In multivariate analysis, these prognostic factors were not significant.
Conclusion: These results confirm the efficacy of external radiotherapy and brachytherapy in the treatment of small anal canal cancers, and point out the need for improving treatment outcome of larger tumors.