A Phase II Study of Capecitabine/Oxaliplatin With Concurrent Radiotherapy in Locally Advanced Squamous Cell Carcinoma of the Anal Canal

Introduction: Squamous cell carcinoma of the anal canal (SCCA) presents a rising incidence in the United States. Standard of care for locally advanced disease is comprised of infusional 5-fluorouracil with mitomycin C or cisplatin concurrent with radiation therapy (RT). We designed this trial to evaluate the efficacy and safety of a more convenient regimen composed of capecitabine and oxaliplatin. Patients and Methods: This was a single-arm, phase II trial, with treatment-naive stage II to IIIB (TX,1-4NxM0) SCCA patients. The regimen was composed of capecitabine (825 mg/m² twice per day for 5 days) and oxaliplatin (50 mg/m² weekly) during weeks 1 through 6, concurrent with RT (XELOX-XRT; group 1). After the first 11 patients, the study was amended to omit chemotherapy during the third and sixth weeks (group 2). The primary objective was 3-year time to treatment failure (TTF) and safety. Secondary objectives were complete response (CR) rate, locoregional control, colostomy-free survival (CFS), and overall survival (OS). Results: Twenty patients were enrolled. Seven patients of group 1 (63%) developed Grade 3 toxicity, which reduced to 22% in Group 2. No Grade 4 toxicities were noted. The median RT dose was 55 Gy. CR occurred in 100% of the 19 patients evaluable for response at 12 to 14 weeks. After a median follow-up of 47.6 months, 2 patients had local recurrence and 1 had distant recurrence. Three-year TTF was 90.0%, with similar rates between groups 1 and 2 (respectively, 90.9% vs. 88.8%, P = .984). Three-year CFS was 90.0%. The median OS has not been reached. Conclusion: The XELOX-XRT regimen is safe, with promising efficacy, and should be explored in larger trials for the treatment of locally advanced SCCA.