Sarcomatoid change in combined hepatocellular carcinoma and cholangiocarcinoma as a poor prognostic factor

Background: Sarcomatoid change is rarely seen in epithelial malignancy that can be observed in diverse organs. Although a sarcomatoid change in combined hepatocellular-cholangiocarcinoma (cHCC-CC) assumed to be a poor prognostic factor, this issue has not been studied due to its rare incidence. In this study, we aimed to identify the oncological impact of sarcomatoid change in patients with cHCC-CC and verify that sarcomatoid change is a poor prognostic factor for resected cHCC-CC. Methods: Between January 2006 and December 2020, 102 patients who underwent surgical resection for cHCC-CC were retrospectively reviewed. The hazard ratio (HR) according to sarcomatoid change was calculated using other known prognostic factors for cHCC-CC. In addition, the patients were divided into two groups according to the sarcomatoid change, and their survival was compared. Results: The multivariate analysis demonstrated that sarcomatoid change in cHCC-CC is a poor prognostic factor {disease-free survival (DFS), HR =3.84 [95% confidence interval (CI): 1.63-9.10], P=0.002; overall survival (OS), HR =3.94 (95% CI: 1.67-9.31), P=0.002}. In the survival analysis, the sarcomatoid change group displayed a worse prognosis compared to the non-sarcomatoid change group {DFS: 4.0 [interquartile range (IQR): 1.2-6.8] vs. 23.0 (IQR: 9.3-36.7) months, P=0.001; OS: 19.0 (IQR: 7.2-30.8) vs. 85.0 (IQR: 31.8-138.2) months, P=0.004}. Conclusions: Sarcomatoid change is a poor prognostic factor for resected cHCC-CC.