Twenty-year experience in the management of squamous cell anal canal carcinoma with interstitial brachytherapy.

OBJECTIVES: The aim of this study was to retrospectively evaluate clinical characteristics, local control, acute and late toxicity, and prognostic factors of patients with anal canal carcinoma treated with brachytherapy.
METHODS: From 1989 to 2009, 38 patients were treated with iridium 192 low-dose-rate (N = 26) or pulsed-dose-rate (N = 12) interstitial brachytherapy at a single institution. The median age was 62 years (range, 38-86 years). The TNM classification was as follows: 10 T1, 22 T2, 5 T3 and 1 T4; 32 N0, 3 N1 and 3 N2. Most patients (32/38) received either a first course of radiochemotherapy (N = 22) or radiotherapy alone (N=10) consisting of a total delivered dose of 45 Gy to the pelvis (range, 32-50) followed by a boost a median of 18 days later of 15-35 Gy (median 20 Gy) to the anal canal. The remaining 6 cases were treated with brachytherapy alone (dose range, 60-65 Gy).
RESULTS: With a median follow-up of 30 months (range, 4-200), 2- and 5-year local control rates were 91% and 87%, respectively. Preservation of the anal sphincter was achieved in 32 patients (84%). Three patients experienced incontinence after brachytherapy. Only 2 patients showed chronic mucositis grade 3/4. Age proved to be a statistically significant prognostic factor for overall survival in the univariate (p = 0.033) and multivariate analyses (p = 0.018). Concurrent chemotherapy with external beam radiotherapy was a statistically significant prognostic factor for disease-free survival in the univariate and multivariate analyses (p = 0.007 and p = 0.044, respectively).
CONCLUSIONS: Interstitial brachytherapy appears to be an effective and well tolerated treatment for anal carcinoma offering both high local tumour control and anal sphincter preservation.