Long-Term Recurrence-Free and Overall Survival Differ Based on Common, Proliferative, and Inflammatory Subtypes After Resection of Intrahepatic Cholangiocarcinoma

Introduction: While generally associated with poor prognosis, intrahepatic cholangiocarcinoma (ICC) can have a heterogeneous presentation and natural history. We sought to identify specific ICC subtypes that may be associated with varied long-term outcomes and patterns of recurrence after liver resection. Methods: Patients who underwent curative-intent resection for ICC from 2000 to 2020 were identified from a multi-institutional database. Hierarchical cluster analysis characterized three ICC subtypes based on morphology (i.e., tumor burden score [TBS]) and biology (i.e., preoperative neutrophil-to-lymphocyte ratio [NLR] and CA19-9 levels). Results: Among 598 patients, the cluster analysis identified three ICC subtypes: Common (n = 300, 50.2%) (median, TBS: 4.5; NLR: 2.4; CA19-9: 38.0 U/mL); Proliferative (n = 246, 41.1%) (median, TBS: 8.8; NLR: 2.9; CA19-9: 71.2 U/mL); Inflammatory (n = 52, 8.7%) (median, TBS: 5.4; NLR: 12.6; CA19-9: 26.7 U/mL). Median overall survival (OS) (Common: 72.0 months; Proliferative: 31.4 months; Inflammatory: 22.9 months) and recurrence-free survival (RFS) (Common: 21.5 months; Proliferative: 11.9 months; Inflammatory: 9.0 months) varied considerably among the different ICC subtypes (all p < 0.001). Even though patients with Inflammatory ICC had more favorable T-(T1/T2, Common: 84.4%; Proliferative: 80.6%; Inflammatory: 86.5%) and N-(N0, Common: 14.0%; Proliferative: 20.7%; Inflammatory: 26.9%) disease, the Inflammatory subtype was associated with a higher incidence of intra- and extrahepatic recurrence (Common: 15.8%; Proliferative: 24.2%; Inflammatory: 28.6%) (all p = 0.01). Conclusions: Cluster analysis identified three distinct subtypes of ICC based on TBS, NLR, and CA19-9. ICC subtype was associated with RFS and OS and predicted worse outcomes among patients. Despite more favorable T- and N-disease, the Inflammatory ICC subtype was associated with worse outcomes ICC subtype should be considered in the prognostic stratification of patients.