The oncologic implications of tumor multiplicity in intrahepatic cholangiocarcinoma: Its prognostic value might be underestimated.

Abstract

611 Background: In the latest staging system of the American Joint Committee on Cancer (AJCC) for intrahepatic cholangiocarcinoma (IHCCC), solitary tumor with vascular invasion and multiple tumors are grouped together as T2. However, recent studies have reported that multifocal IHCCC have worse prognosis than a single lesion. This study aimed to investigate risk factors of IHCCC and to explore the prognostic significance of multiplicity identified by surgical resection. Methods: A total of 277 patients underwent surgery for IHCCC from 2010 to 2019 and the clinicopathological data were retrospectively reviewed. Risk factor analysis was performed to identify variables associated with survival of resected IHCCC. Survival outcomes were compared between patients with solitary tumors and those with multiple tumors. Results: In multivariable analysis, presence of preoperative symptoms, tumor size, lymph node ratio, multiplicity, and tumor differentiation were risk factors for survival. Among 82 patients with T2, overall survival was significantly better in patients with solitary tumors (sT2) than in those with multiple tumors (mT2) (p = 0.017). Survival was compared among patients with stage II-sT2, stage II-mT2, and stage III. Stage II-sT2 group showed prolonged survival than those with stage II-mT2 or stage III. Survival of stage II-mT2 patients was not statistically different from that of stage III patients. Conclusions: Tumor multiplicity was an independent risk factor for overall survival of IHCCC after surgical resection. Patients with multiple tumors showed poorer survival than patients with a single tumor. The oncologic significance of multiplicity in IHCCC should be reappraised and be reflected in the next update of staging system.[Table: see text]