Chemoradiotherapy for squamous cell carcinoma of the anal canal: Comparison of one versus two cycles mitomycin-C.

Abstract

Concurrent chemoradiotherapy with 5-fluorouracil (5-FU) and mitomycin-C (MMC) is standard treatment for anal cancer. Randomized clinical trials in Europe have used 1 cycle MMC, while North American studies use 2 cycles. We compared treatment outcomes between patients treated with either 1 or 2 cycles of concurrent MMC. 217 consecutive patients were treated definitively with chemoradiation from 2004 to 2012 in an integrated health system. Concurrent chemotherapy regimen depended on individual practice, and consisted of 2 cycles 5-FU (1000 mg/m(2)/day on days 1-4 and 29-32), along with MMC (10-15 mg/m(2)), given on either day 1 alone (n = 154), or days 1 and 29 (n = 63). Outcomes included progression-free (PFS), cancer-specific (CSS), overall (OS), and colostomy-free survival (CFS), as well as toxicity criteria. Median age 60 years, 70% female, 52% T3-T4, and 40% node-positive. Median follow-up 26 months. At 2 years, outcomes were: PFS 80%, CSS 89%, OS 86%, and CFS 88%. There was no difference in PFS (HR 0.85, 95% CI 0.37-1.92), CSS (HR 0.32, 95% CI 0.07-1.42), OS (HR 0.67, 95% CI 0.25-1.83), or CFS (HR 0.91, 95% CI 0.31-2.67) between the MMC1 and MMC2 groups. Stage and male gender were predictive of worse outcomes. Acute grade ⩾ 2 toxicities were worse in the MMC2 group. There were 3 treatment-related deaths, all in the MMC2 group. This study suggests that MMC1 is efficacious and may be an alternative to MMC2 in patients with anal cancer treated with definitive chemoradiation, with the potential for less acute treatment-related toxicity. Randomized trials comparing these two regimens could be considered.