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.