Prognostic markers including immune and inflammatory factors predict outcomes in patients receiving postoperative radiation therapy for cholangiocarcinoma.

Abstract

This study aimed to analyze treatment outcomes and prognostic markers, including immune and inflammatory factors, of postoperative radiation therapy (RT) administered to patients with cholangiocarcinoma (CCA). We retrospectively included 59 patients with CCA who underwent surgery and postoperative RT with curative intent from 2004 to 2019. Patients received external irradiation (50Gy in 25 fractions) using three-dimensional RT. We analyzed prognostic factors of inflammation, such as pre-RT platelet count, hemoglobin, lymphocyte count ratio (LCR) of the leukocyte count, platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR). Tumor stages were distributed as follows: I (n=8), II (n=25), III (n=15), and IVA (n=11). The median follow-up was 24 months. Two-year overall survival (OS), cause-specific survival (CSS), progression-free survival (PFS), and locoregional control (LRC) rates were 59.5%, 62.0%, 40.1%, and 66.7%, respectively. Univariate analysis revealed that lower LCR was significantly associated with shorter PFS (p=0.0446). There was no significant difference between the median baseline values of PLR and NLR; and age ≥75, positive regional lymph node metastases (N+), and chemotherapy after RT were significantly associated with poor OS. Multivariate analysis revealed a significant association of N+ with worse OS, PFS, and CSS and that lower LCR was significantly associated with better PFS (p=0.0234). Among late toxicity events, two patients (3.38%) were suspected with therapy-related liver toxicity. Lower LCR before RT was a better prognostic factor for postoperative RT of patients with CCA.