Prediction of overall survival in resectable intrahepatic cholangiocarcinoma: IS(ICC)‐applied prediction model

Intrahepatic cholangiocarcinoma (ICC) remains a highly heterogeneous disease with poor prognosis. Tumor‐infiltrating lymphocytes were predictive in various cancers, but their prognostic value in ICC is less clear. A total of 168 ICC patients who had received liver resection were enrolled and assigned to the derivation cohort. Sixteen immune markers in tumor and peritumor regions were examined by immunohistochemistry. A least absolute shrinkage and selection operator model was used to identify prognostic markers and to establish an immune signature for ICC (IS(ICC)). An IS(ICC)‐applied prediction model was built and validated in another independent dataset. Five immune features, including CD3(peritumor (P)), CD57(P), CD45RA(P), CD66b(intratumoral (T)) and PD‐L1(P), were identified and integrated into an individualized IS(ICC) for each patient. Seven prognostic predictors, including total bilirubin, tumor numbers, CEA, CA19‐9, GGT, HBsAg and IS(ICC), were integrated into the final model. The C‐index of the IS(ICC)‐applied prediction model was 0.719 (95% CI, 0.660‐0.777) in the derivation cohort and 0.667 (95% CI, 0.581‐0.732) in the validation cohort. Compared with the conventional staging systems, the new model presented better homogeneity and a lower Akaike information criteria value in ICC. The IS(ICC)‐applied prediction model may provide a better prediction performance for the overall survival of patients with resectable ICC in clinical practice.