Prognostic Nomogram Based on Histological Characteristics of Fibrotic Tumor Stroma in Patients Who Underwent Curative Resection for Intrahepatic Cholangiocarcinoma.

Abstract

Fibrotic tumor stroma (FTS) has been implicated in cancer promotion in several neoplasms. The histological features of FTS are convenient and easily accessible in clinical routine in intrahepatic cholangiocarcinoma (ICC) specimens. The goal of this study was to explore prognostic impacts of the quantity and maturity of FTS on surgical ICC patients. Moreover, we aimed to propose an efficient prognostic nomogram for postoperative ICC patients. The clinical profiles of 154 consecutive postoperative ICC patients were retrospectively analyzed. Tumor-stroma ratio and morphological maturity of FTS were evaluated on hematoxylin and eosin-stained tumor sections. CD3, CD8, and α-smooth muscle actin (α-SMA) staining were performed on corresponding tissue microarrays. The nomogram was established on variables selected by multivariate analyses and was validated in 10-fold cross-validation. Rich tumor stroma and strong α-SMA expression were associated with poor overall survival (OS). However, in multivariate analyses, these two biomarkers failed to stratify both OS and recurrence-free survival (RFS). Immature FTS was correlated with tumor multiplicity, advanced clinical stage, and sparser CD3 and CD8 positive tumor-infiltrating lymphocytes (TILs) and was identified as an independent prognostic indicator for both OS and RFS. The nomogram comprising FTS maturity, tumor number, microvascular invasion, and lymph node metastasis possessed higher predictive power relative to conventional staging systems. Immature FTS was an independent risk factor for survival and was associated with sparser CD3 and CD8 positive TILs in ICC. The prognostic nomogram integrating the maturity of FTS offers a more accurate risk stratification for postoperative ICC patients. Accumulating evidence has suggested that fibrotic components in tumor microenvironment (TME) play a complicated and vital role in TME reprogramming and cancer progression. However, in clinical practice, the evaluation of fibrotic tumor stroma (FTS) is still neglected to some extent. This study's findings indicated that, in intrahepatic cholangiocarcinoma (ICC), the histological maturity of FTS is a robust prognostic indicator for patients who underwent curative resection. Moreover, prognostic nomogram constructed on the maturity of FTS possessed higher predictive power relative to the conventional tumor-node-metastasis staging systems. Taken together, the evaluation of FTS should be emphasized in clinical routine for more accurate prognostic prediction in postoperative ICC patients.