A meta-analysis of the efficacy of postoperative adjuvant radiotherapy versus no radiotherapy for extrahepatic cholangiocarcinoma and gallbladder carcinoma

Objective The benefit of adjuvant radiotherapy (ART) for extrahepatic cholangiocarcinoma (EHCC) and gallbladder carcinoma (GBC) is unclear, with conflicting results from nonrandomized studies. We reported a meta-analysis to determine the impact of adjuvant radiotherapy on survival. Methods PubMed, EMBASE, Cochrane Library and CNKI databases were searched to identify clinical trials of postoperative ART versus no radiotherapy for EHCC and GBC. The obtained data were analyzed using RevMan 5.3 and Stata 14.0 statistical software. Differences between two groups were estimated by calculating the odds ratio (OR) and 95% confidence interval (CI). Results A total of 21 clinical trials involving 1465 EHCC and GBC patients were selected according to the inclusion and exclusion criteria and included in this meta-analysis. The meta-analysis showed the following: The 5-year overall survival (OS) rate was higher in the ART group than in the no radiotherapy group (OR = 0.63; 95% CI = 0.50-0.81, p = 0.0002). The 5-year OS rate was significantly higher for those with lymph node-positive disease (OR = 0.15; 95% CI 0.07-0.35; p < 0.00001) and margin-positive disease (OR = 0.40; 95% CI 0.19-0.85; p = 0.02) in the ART group than in the no radiotherapy group. ART had a tendency to bring benefit to the 5-year OS of patients with margin-negative disease but the difference was not statistically significant (OR = 0.57, 95% CI 0.30-1,07, p = 0.08). The local recurrence rate was significantly lower in the ART group than in the no radiotherapy group (OR = 0.54; 95% CI = 0.38-0.76, p = 0.0004), and there was no significant difference in the distant metastasis rate between the two groups (OR = 1.33; 95% CI = 0.95-1.87, p = 0.10). Conclusions A meta-analysis of the existing study results showed that compared with no radiotherapy, ART is an effective postoperative treatment for EHCC and GBC.