Impact of Surgical Margin on Prognosis and Recurrence in Intrahepatic Cholangiocarcinoma

This study investigated the impact of surgical margin (SM) on the prognosis and recurrence of intrahepatic cholangiocarcinoma (ICC). The impact of SM on the prognosis remains controversial. We analyzed 58 ICC patients who underwent macroscopically curative surgery. The patients were classified into 5 categories according to the SM; microscopically positive (R1), 0 to <1 mm, 1 to <5 mm, 5 to <10 mm, and ≥10 mm. The overall survival (OS) rate was significantly different for SM <1 mm or SM ≥1 mm; therefore, the cutoff value was set at 1 mm. Twenty-five patients (43.1%) had an SM <1 mm, and 33 (56.9%) had an SM ≥1 mm. The multivariate analysis identified SM <1 mm (P = 0.027) as an independent predictor of OS. After the propensity score matching based on tumor-related factors, the OS rate of the SM <1 mm group was significantly lower than that of the SM ≥1 mm group (P = 0.013). Peritoneal dissemination was significantly increased in the SM <1 mm group (P = 0.007). The postrecurrence survival rate of the SM <1 mm group was significantly lower than that of the SM ≥1 mm group (P = 0.012). This study suggests that an SM of at least 1 mm should be achieved regardless of tumor status during ICC resection. An SM < 1 mm may indicate a higher risk of peritoneal dissemination.