Beyond anatomy: tumor morphology stratifies survival after curative-intent resection of cholangiocarcinoma involving the hepatic hilum.

BACKGROUND

The clinical distinction between perihilar cholangiocarcinoma (pCCA) and mass-forming intrahepatic cholangiocarcinoma (m-iCCA) with hilar involvement is controversial. Although they are managed with similar surgical procedures, their prognoses may differ. This study compares their clinicopathological features and outcomes to determine if they are distinct entities, advocating for a morphology-based classification.

METHODS

We retrospectively reviewed 212 patients who underwent curative-intent resection for hilar cholangiocarcinoma (2013-2018). Patients were classified as having m-iCCA (n = 45), mass-forming pCCA (m-pCCA; n = 35), and periductal-infiltrating/intraductal pCCA (pi-pCCA; n = 132). Clinicopathological data and survival outcomes were compared.

RESULTS

Patients with m-iCCA presented with more aggressive features than those with pi-pCCA, including larger tumors (median, 7 vs 2.5 cm; P <.001) and higher rates of vascular invasion (P <.001) and lymph node metastasis (P =.035). Survival was significantly worse for patients with m-iCCA (median, 10.0 vs 16.4 months; P =.038). Notably, m-pCCA shared aggressive features with m-iCCA. For m-iCCA, aggressive biology (perineural invasion) drove prognosis, whereas for pCCA subtypes, factors such as margin status and nodal involvement were paramount. R1 resection did not significantly impact survival in the m-iCCA group, suggesting that its aggressive biology outweighs the benefits of local control.

CONCLUSION

Among patients undergoing curative-intent resection for cholangiocarcinoma involving the hepatic hilum, survival differed according to tumor morphology and anatomical category. Mass-forming tumors, including m-iCCA and m-pCCA, demonstrated more aggressive clinicopathological features than pi-pCCA. These findings suggest that tumor morphology may refine prognostic stratification beyond anatomical origin alone and should be considered when tailoring surgical and perioperative treatment strategies.