Prognostic impact of perineural invasion in intrahepatic cholangiocarcinoma: multicentre study

Among 1095 patients who underwent resection of ICC, PNI was present in 239 (21.8 per cent). The presence of PNI was associated with worse disease-free survival, as well as overall survival; especially among those with AJCC T1-2 (981 patients) or N0 (249) disease, PNI remained associated with worse DFS. PNI was a strong independent predictor of tumour recurrence and long-term survival after resection with curative intent, even among patients early-stage disease.Background The aim of this study was to investigate the prognostic impact of perineural invasion (PNI) on tumour recurrence and survival among patients with resected intrahepatic cholangiocarcinoma (ICC). Methods This was a multicentre, retrospective study of patients who underwent resection with curative intent for ICC between 2000 and 2017. The relationship between PNI, clinicopathological characteristics, and long-term survival was analysed in the overall cohort and the subset of patients with early-stage ICC. Results Among 1095 patients who underwent resection of ICC, PNI was present in 239 (21.8 per cent). In univariable analysis, PNI was associated with worse disease-free survival (DFS) (median 13.2 versus 16.1 months for patients with and without PNI respectively; P = 0.038) and overall survival (OS) (26.4 versus 41.5 months; P < 0.001). In multivariable analysis, PNI was an independent risk factor associated with reduced DFS (hazard ratio (HR) 1.56, 95 per cent c.i. 1.06 to 2.13; P = 0.019) and OS (HR 1.74, 1.16 to 2.60; P = 0.007). In subgroup analysis of patients with early-stage disease (AJCC T1-2, 981 patients; or N0, 249 patients), PNI remained associated with worse DFS (T1-2: median 13.7 versus 16.6 months in patients with and without PNI respectively, P = 0.019; N0: 11.7 versus 17.5 months, P = 0.022) and OS (T1-2: 28.5 versus 45.7 months, P < 0.001; N0: 34.9 versus 47.5 months, P = 0.036). Conclusion PNI is a strong independent predictor of tumour recurrence and long-term survival following resection of ICC with curative intent, even among patients with early-stage disease. The presence of PNI should be assessed routinely.