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.
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