Comparison of definitive chemoradiation with 5-fluorouracil versus capecitabine in anal cancer

Abstract

Background: Capecitabine (Cap) is an established treatment alternative to 5-fluorouracil (5-FU) for chemoradiation in rectal cancer. Few studies have compared the two agents in anal cancer. We compared outcomes and toxicities using Cap versus 5-FU in non-metastatic anal cancer patients at Stanford. Methods: All non-metastatic anal cancer patients treated with definitive chemoradiation at Stanford from 1997–2016 were included. Fisher’s exact and Mann-Whitney U tests were used to compare nominal and continuous variables. Gray’s test was used to compare incidence of recurrence and colostomy, and Log-rank test was used to compare survival. Results: Sixty-eight patients were included. Thirty-six patients received Cap and 32 received 5-FU (12 received standard 5-FU and 20 received low-dose continuous 5-FU). Patient characteristics were similar between the two groups. There was no difference in the 3-year overall and disease-specific survival between Cap and 5-FU (94% vs. 80%, P=0.197; 100% vs. 86%, P=0.051). Overall incidence of recurrence was equivalent between Cap and 5-FU (11% vs. 13%, P=0.703), but incidence of locoregional recurrence was higher in the 5-FU group (0% vs. 13%, P=0.042); patients treated with Cap had longer recurrence-free intervals (18 vs. 6 months, P=0.400), and all recurrences were distant. More colostomies were needed with 5-FU (3% vs. 13%, P=0.133). Toxicities were similar between the two groups. The most common grade ≥2 toxicities were dermatitis (77%), anal pain (78%), and diarrhea (56%). Conclusions: Overall survival (OS), cancer-specific survival and incidence of recurrence were equivalent between Cap and 5-FU in anal cancer. Patients treated with Cap had statistically significant lower incidence of loco-regional relapses.