MULTIPARAMETRIC EVALUATION OF INTRAHEPATIC CHOLANGIOCARCINOMA: CLINICAL AND RADIOLOGICAL ANALYSIS FOR PREDICTING PROGNOSIS AFTER LIVER RESECTION

Background: Intrahepatic cholangiocarcinoma (iCCA) is a biologically heterogeneous malignancy associated with poor postoperative outcomes even after curative-intent resection. Histopathologic subtypes of iCCA are associated with distinct clinical features and prognoses. Increasing evidence suggests that computed tomography (CT) and magnetic resonance imaging (MRI) features may reflect underlying tumor biology and provide prognostic information. However, most staging systems for iCCA are based on postoperative pathological results, limiting preoperative prognostic stratification.Purpose: To evaluate the association between preoperative CT and MRI features and histopathologic subtypes, and to assess the prognostic value of imaging and clinicopathological findings for predicting recurrence-free survival (RFS) and overall survival (OS) in patients with solitary mass-forming iCCA undergoing curative-intent surgical resection.Materials and Methods: This retrospective multicenter study included patients with solitary mass-forming iCCA who underwent curative-intent resection between June 2004 and June 2024. Two radiologists independently reviewed preoperative CT and MRI exams to evaluate tumor imaging features. Histopathologic evaluation of resected specimens was performed by two liver pathologists at each center. Associations between imaging features and histopathologic subtypes were analyzed, and differences in imaging characteristics were compared between small-duct and non-small-duct iCCA subtypes. Recurrence-free survival (RFS) and overall survival (OS) were assessed using Kaplan–Meier analysis and Cox proportional hazards models.Results: A total of 190 patients (median age, 65 years [IQR, 58.0-73.0 years]; 88 [46.3%] male patients) with solitary resected mass-forming iCCA were included. Small-duct iCCA was the predominant histopathologic subtype (166/190, 87.4%), followed by large-duct subtype (17/190, 8.9%) and other rare subtypes (7/190, 3.7%). Imaging features differed between histologic subtypes. Small-duct iCCA were significantly larger than non-small-duct subtype (median size, 58.0 mm [IQR, 40.0-81.3] vs 43.5 mm [IQR, 30.0-65.0]; P = .021), and more frequently demonstrated rim arterial phase hyperenhancement on CT (73.3% vs 35.0%; P = .001). On MRI, small-duct iCCA more frequently showed delayed central enhancement (86.5% vs 63.6%; P = .014), marked diffusion restriction (68.3% vs 31.6%; P = .002), and targetoid diffusion restriction (70.6% vs 42.1%; P = .014), whereas non-smooth margins were more common in non-small-duct subtype (77.3% vs 46.6%; P = .008). Despite these imaging differences, Kaplan-Meier analysis showed no significant differences in RFS or OS between subtypes. In the CT cohort, vascular invasion (HR 1.58; P = .033), lymph node metastasis (HR 1.74; P = .034), and intratumoral necrosis on CT (HR 1.50; P = .049) were independently associated with shorter RFS. Lymph node metastasis (HR 2.99; P = .001) and intratumoral necrosis on CT (HR 1.84; P = .014) were independently associated with worse OS. In the MRI cohort, lymph node metastasis (HR 2.76; P = .005), advanced liver fibrosis (F3–F4) (HR 3.08; P = .001), and tumor necrosis (HR 1.76; P = .039) were independent predictors of poorer OS. Conversely, delayed central enhancement (HR 0.48; P = .015) and capsule appearance (HR 0.20; P = .030) were independently associated with improved survival.Conclusion: Preoperative imaging features on CT and MRI are associated with histopathologic phenotypes of intrahepatic cholangiocarcinoma and provide clinically relevant prognostic information in patients with solitary mass-forming iCCA undergoing curative-intent resection. Although imaging findings may suggest underlying tumor subtype, postoperative outcomes appear to be primarily driven by markers of tumor aggressiveness such as lymph node metastasis, microvascular invasion, intratumoral necrosis. Noninvasive imaging biomarkers may therefore contribute to improving preoperative risk stratification and support clinical decision-making.