Influence of Perineural (Pn), Lymphangio (L) and Vascular (V) Invasion on Survival after Resection of Perihilar Cholangiocarcinoma.

Simple Summary: Perihilar cholangiocarcinoma is a rare biliary cancer with a poor prognosis, even after surgery. This study aimed to assess the impact of perineural (Pn), lymphangio (L), and vascular (V) invasion on overall survival following surgical resection. Data from 214 patients who underwent surgery between 2013 and 2023 were analyzed. Of these, curative intended resection was achieved in 168 patients (78.5%). Perineural, lymphangio and vascular invasion were present in 79.2%, 17.3% and 14.3% of patients, respectively. L1 and V1 were significantly associated with each other. Vascular invasion was associated with a significantly worse overall survival, while perineural invasion showed a trend toward worse overall survival, although this was not statistically significant. In Bismuth type IV tumors, both L1 and V1 were significantly linked to poorer overall survival. Furthermore, the combination of Pn1 with the presence of either L1 or V1 (or both) was associated with worse overall survival, underscoring the prognostic importance of these factors, particularly in Bismuth type IV tumors. Introduction: Perihilar cholangiocarcinoma is a rare malignancy of the biliary tract, for which surgery remains the treatment of choice. However, even after radical resection, the prognosis is poor. In addition to tumor size, depth of invasion and nodal/metastatic status, the TNM classification includes additional parameters such as perineural (Pn), lymphangio (L) and vascular (V) invasion. The prognostic impact of these factors is not yet fully understood. The aim of this study was to investigate the influence of these parameters on overall survival after resection of perihilar cholangiocarcinoma. Material and Methods: Data from all patients who underwent surgical exploration for perihilar cholangiocarcinoma between January 2013 and December 2023 were included into an institutional database. The impact of perineural, lymphangio and vascular invasion on overall survival was analyzed. Results: Over the 11-year period, a total of 214 patients underwent surgical exploration for perihilar cholangiocarcinoma. Curative intended resection was possible in 168 patients (78.5%). Perineural invasion, lymphangio invasion and vascular invasion were present in 79.2%, in 17.3% and in 14.3% of patients, respectively. Cross tabulation revealed a significant association between the presence of L1 and V1 (p = 0.006). There was also a significant association of Pn1, L1, and V1 with R-status (p = 0.010; p = 0.006 and p ≤ 0.001). While V1 was associated with significantly worse overall survival across the entire cohort, Pn1 alone showed only a tendency towards worse overall survival without reaching statistical significance. In Bismuth type IV, both L1 and V1, but not Pn1, were significantly associated with worse overall survival (p = 0.001; p = 0.017 and p = 0.065). Conclusions: Perineural invasion is very common in perihilar cholangiocarcinoma. Although Pn1 was associated with a tendency toward worse survival, it did not reach statistical significance. In contrast, vascular invasion significantly worsened overall survival in the entire cohort, and lymphangio invasion was linked to worse overall survival in Bismuth type IV tumors. The combination of perineural invasion with positivity of more than one additional factor (either L or V) was also associated with worse overall survival. In patients with Bismuth type IV, these pathological markers appeared to have even greater prognostic relevance. [ABSTRACT FROM AUTHOR]