Effect of surgical margin width after R0 resection for intrahepatic cholangiocarcinoma: A nationwide survey of the Liver Cancer Study Group of Japan

Background: Data are inconsistent regarding the effects of a wide surgical margin for intrahepatic cholangiocarcinoma on recurrence-free survival and overall survival. This study was performed to investigate the effect of surgical margin width in patients undergoing R0 resection for intrahepatic cholangiocarcinoma, using a nationwide database in Japan. Methods: In total, 635 patients with intrahepatic cholangiocarcinoma who were treated by an R0 resection from 2000 to 2007 were identified from the database of a Japanese nationwide survey. Patients were divided into quartiles of the surgical margin width as follows: marginal (<1 mm), narrow (1–4 mm), intermediate (5–9 mm), and wide groups (≥10 mm). Multivariable Cox regression models for recurrence-free survival and overall survival were constructed with adjustment for preoperative and postoperative clinicopathologic factors. Results: Compared with the marginal group, the risk-adjusted hazard ratios (95% confidence intervals) in the narrow, intermediate, and wide groups for recurrence-free survival were 0.92 (0.62–1.37), 0.91 (0.61–1.37), and 0.81 (0.56–1.17), and those for overall survival were 0.79 (0.51–1.24), 0.93 (0.59–1.47), and 0.70 (0.46–1.08), respectively. In 398 patients without lymph node metastasis, the hazard ratios for overall survival were 0.62 (0.34–1.11), 0.63 (0.34–1.17), and 0.51 (0.29–0.90), and those of mass-forming type intrahepatic cholangiocarcinoma were 0.48 (0.21–1.08), 0.43 (0.19–0.96), and 0.40 (0.19–0.82), respectively. Conclusion: Surgical margin width appears to have a limited effect on the prognosis of intrahepatic cholangiocarcinoma except in patients without lymph node metastasis, where a wide surgical margin is associated with favorable outcomes. This survival benefit of a wide surgical margin is especially apparent for the mass-forming type intrahepatic cholangiocarcinoma.