Analysis of risk factors for perineural invasion and efficacy of adjuvant chemotherapy in patients with intrahepatic cholangiocarcinoma

The prognostic significance of perineural invasion (PNI) in intrahepatic cholangiocarcinoma (ICC) has gained increasing attention. There is still controversy over whether PNI can be used as a basis for selecting individuals who benefit from adjuvant chemotherapy (ACT). This study aims to identify the risk factors for PNI and assess the impact of ACT in ICC patients with or without PNI to guide clinical decision-making. A total of 254 patients who underwent curative-intent resection for ICC in a high-volume medical center were retrospectively analyzed. Survival analysis was conducted using the Kaplan-Meier method and log-rank test, with univariate and multivariate Cox proportional hazards regression models used for prognostic analysis. Among the 254 patients who underwent curative-intent resection for ICC, 46 (17.1%) were found to combine PNI. Multivariate analysis revealed that CA 19-9 level, hepatolithiasis, major vascular invasion, and N stage were independent risk factors for PNI ( P <0.05). Prognosis analysis showed that CA19-9 level, hepatolithiasis, tumor numbers, PNI, and N stage were independent risk factors for OS ( P <0.05), while ACT was an independent protective factor ( P <0.05). Similarly, CA125 level, tumor numbers, PNI, and N stage were independent risk factors for RFS ( P <0.05), with ACT also serving as an independent protective factor ( P <0.05). Subgroup analysis showed that ACT effectively prolonged median OS ( P =0.041) and RFS ( P =0.007) in ICC patients with PNI. PNI is an independent risk factor for both OS and RFS in patients with ICC after curative-intent resection, and ACT can significantly improve the prognosis in ICC patients with PNI.