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

BACKGROUND AND PURPOSE: 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.

MATERIAL AND METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.