Capecitabine versus 5-fluorouracil in neoadjuvant chemoradiotherapy of locally advanced rectal cancer A meta-analysis

Background: The differences in efficacy between capecitabine and 5-fuorouracil (5-FU) in neoadjuvant chemoradiotherapy (CRT) of locally advanced rectal cancer (LARC) are not well recognized. We performed this meta-analysis to analyze the effect of capecitabine and 5-FU on neoadjuvant CRT to more accurately understand the differences between the 2 drugs. Methods: MEDLINE, EMBASE, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Database were performed to identify all published studies investigating the efficacy of capecitabine in neoadjuvant CRT of LARC versus 5-FU before August, 2017. Primary endpoint was the odds ratio (OR) for improving pathological complete response (pCR) rate of patients with LARC. Secondary endpoints were the ORs of efficiency for downstaging tumor and increasing R0 resection in patients with LARC. Safety analyses were also performed. The OR was the principal measurement of effect, which was calculated as capecitabine group versus 5-FU group, and was presented as a point estimate with 95% confidence intervals (CIs). All calculations and statistical tests were performed using RevMan 5.3 software. Results: In all, 2916 patients with LARC enrolled in the 10 studies were divided into capecitabine group (n=1451) and 5-FU group (n=1465). The meta-analysis showed that capecitabine improved pCR (OR 1.34, 95% CI 1.10-1.63), and R0 resection rate (OR 1.92, 95% CI 1.10-3.36). There were no statistically significant differences either in overall downstaging rate (OR 1.31, 95% CI 0.79-2.16) or in the tumor downstaging rate (OR 1.24, 95% CI 0.79-1.92), but there was a significant difference of the nodal downstaging rate between the 2 groups (OR 1.68, 95% CI 1.11-2.54). There was no statistically significant difference in sphincter preservation rate between the 2 groups (OR 1.36, 95% CI 0.96-1.92). No obvious safety concerns about mortality and complications were raised in these studies. There were no statistically significant differences in 3-year disease-free-survival (OR 1.29, 95% CI 0.75-2.20), and in grade 3 to 4 acute toxicity during CRT (OR 0.63, 95% CI 0.31-1.30). Conclusions: Compared with 5-FU-based neoadjuvant CRT, capecitabine-based neoadjuvant CRT can safely improve pCR, nodal down-staging, and R0 resection of patients with LARC.