The effect of adjuvant chemotherapy in resectable cholangiocarcinoma: A meta-analysis and systematic review

Background: The benefit of adjuvant chemotherapy for resectable cholangiocarcinoma remains unclear due to the lack of randomized control studies. This study aimed to investigate the possible benefit of postoperative adjuvant chemotherapy for resectable cholangiocarcinoma. Data sources: Relevant research articles published before 1 st March 2018 in Pub Med, Embase and the Cochrane library databases were retrieved. Published data were extracted and analyzed by RevMan 5.3, and the results were presented as hazard ratios(HRs) [95% confidence intervals(CI)] and forest plots. Results: One prospective and eighteen retrospective studies were included, with a total number of 11,458 patients, 4696 of whom received postoperative chemotherapy. There was a significant improvement of the overall survival(OS) for patients who underwent operation + adjuvant chemotherapy compared to those who underwent operation alone(HR = 0.61; P < 0.001). Subgroup analyses show that the postoperative chemotherapy group compared with operation alone group are indicated as follows: hilar cholangiocarcinoma group(HR = 0.60; P < 0.001), intrahepatic cholangiocarcinoma group(HR = 0.60; P < 0.001), R1 resection group(HR = 0.71; P = 0.04), LN-positive diagnosis group(HR = 0.58; P < 0.001), gemcitabine-based chemotherapy group(HR = 0.42; P < 0.001), distal cholangiocarcinoma group(HR = 0.48; P = 0.17), R0 resection group(HR = 0.69; P = 0.43), and 5-flurouracil-based chemotherapy group(HR = 0.90; P = 0.66), respectively. Conclusions: Postoperative adjuvant chemotherapy can improve the OS in intrahepatic and hilar cholangiocarcinoma patients. However, distal cholangiocarcinoma patients gain no benefit from postoperative adjuvant chemotherapy. Prospective randomized trials are warranted in order to define the standard chemotherapy regimen.