Experience with split-course external beam irradiation ± chemotherapy and integrated Ir-192 high-dose-rate brachytherapy in the treatment of primary carcinomas of the anal canal

Abstract Purpose: The effect of the treatment of anal cancer by performing a high-dose-rate (HDR) brachytherapy boost during a short split between the external beam radiotherapy series (EBR) ± chemotherapy was investigated. Methods and Materials: Thirty-nine patients with anal canal cancers, stages T1–T4 N0–2 M0, were treated with split-course EBR (50–50.4 Gy) and a Iridium 192 ( 192 Ir-) HDR boost (6 Gy) performed during the 1–2-week split. Patients who failed to achieve a complete tumor response received additional brachytherapy. Chemotherapy with 5-fluorouracil and mitomycin C was offered to patients with tumors > 3 cm and employed concomitantly on days 1–5 and day 1, respectively, of each EBR series. Results: Follow-up ranged from 3 to 140 months (median 31). Median treatment duration was 56 days. The 3-year (5-year) actuarial rates of locoregional control (LRC) and disease-specific survival (DSS) were 81% (76%) and 80% (76%), respectively. The crude rate of anal preservation was 77% overall, and 97% in patients in whom LRC was achieved. Uncompromised anal function was recorded in 93% of these patients. The actuarial 3-year (5-year) rate of colostomy-free survival (CFS) was 78% (73%). There was a statistically significant difference in LRC and DSS according to stage, tumor size, and nodal status. Complications requiring surgical intervention occurred in 7.6% of patients. Conclusion: The integration of the HDR boost in a split-course EBR regimen ± chemotherapy resulted in excellent sphincter function without an increase of severe complications and with rates of LRC, DSS, and CFS, which compare favorably with those reported in the literature.