External beam radiotherapy plus brachytherapy boost in treatment of anal canal carcinoma

Radiotherapy has been the standard treatment of anal canal carcinoma for the last three decades. However, there are still many open questions such as optimal radiation technique, adequate boost dose or best chemotherapy regimen. Beside cure and local control, other important goals are sphincter salvage and avoidance of a permanent colostomy, i.e. morbidity minimization.

At the Institute for Oncology and Radiology of Serbia, between March 1997 and May 2004, patients with anal canal carcinoma were treated with combined external beam radiotherapy and brachytherapy boost as primary treatment modality. Initially, external beam radiotherapy was applied with two opposed parallel fields and dose ranged from 40-50 Gy and after that patient continued the treatment with brachytherapy boost (intraluminal or interstitial) with doses ranged from 10-25 Gy. Total tumor dose in combined radiotherapy treatment ranged from 55-70 Gy.

Out of 21 patients, acute complications were registered in 15 patients (71.4%) and the most frequent was dermatitis. Complete response after radiotherapy was registered in 17 patients (81%). In the median follow up time of 42 months, five-year overall survival was 71% and disease free survival was 61%. Late sequelas were registered in 14 patients (66.7%), but they were low grade.

Our study shows results using external beam radiotherapy and brachytherapy boost as single modality treatment, but we need more randomized trial to improve better local control and minimize toxicity.