Mri-based Ki-67 prediction for intrahepatic cholangiocarcinoma: Risk stratification and treatment efficacy prediction

Ki-67 is a marker of tumor aggressiveness and poor prognosis in intrahepatic cholangiocarcinoma (iCCA). This study aimed to develop an MRI-based model to predict Ki-67 expression in iCCA and evaluate its therapeutic benefit from systemic treatment.

255 pathologically confirmed iCCA patients who underwent curative surgery (179 training, 76 validation) and 51 advanced iCCA patients receiving combined systemic targeted-immunotherapy were retrospectively included. Clinical and MRI features were compared between Ki-67 status. Univariate and multivariate regression analyses identified independent predictors. Survival analysis was conducted and compared between MRI-predicted high and low Ki-67 groups in patients receiving combined targeted-immunotherapy.

Patients with high histologic Ki-67 had shorter postoperative recurrence-free survival (median RFS 9.0 vs 16.8 months; P = 0.018). Multivariate analysis revealed that patient gender (odds ratio = 2.31, P = 0.032), T2-weighted central brightness (odds ratio = 3.247, P = 0.003) and tumor apparent diffusion coefficient (ADC) values (odds ratio = 0.996, P < 0.001) were independent predictors of Ki-67 status. The combined predictive model yielded AUCs of 0.789 [95%CI 0.719, 0.859] in the training cohort and 0.753 [95%CI 0.641, 0.845] in the validation cohort. In advanced iCCA patients receiving combined targeted-immunotherapy, MRI-predicted high Ki-67 group had a lower objective response rate (31.8% vs. 62.1%, P = 0.032) and shorter progression-free survival (median 8.0 vs. 16.0 months; P < 0.001) compared to predicted low Ki-67 group.

The MRI-based model incorporating patient gender, T2-weighted central brightness and tumor ADC values effectively predicts Ki-67 expression in iCCA. This non-invasive biomarker may aid in treatment efficacy prediction and risk stratification for systemic targeted-immunotherapy.