Prognostic Significance Of Lymphocyte Ratio In Postoperative Radiation Therapy For Cholangiocarcinoma

Abstract

The aim of this analysis was the treatment outcomes and immune and inflammatory prognostic factors of postoperative radiation therapy (RT) in patients for Cholangiocarcinoma (CCA). The postoperative radiation therapy in patients for CCA is still controversial. We included 59 postoperative CCA patients who received surgery and postoperative RT with curative intent from 2004 to 2019, in this retrospective analysis. Patients received external irradiation at a planned total dose of 50 Gy in 25 fractions with three-dimensional RT. Photon radiation therapy was delivered, using 2 to 4 beams. Fraction size was 1.8–2 Gy and was delivered daily, 5 days per week, using 15 MV X-rays and a shrinking field technique. Overall survival (OS), cause-specific survival (CSS), progression-free survival (PFS), and loco-regional control rate (LRC) rates from the beginning of RT treatment were calculated with Kaplan-Meier curves. Analyses of prognostic factors used univariate and multivariate Cox proportional-hazards regression models. Median follow-up time was 24 (range: 2–183) months. At 2 years, the OS was 59.52% (95% confidence interval [CI]:35.8-62.5), CSS was 62.03% (95% CI:39.2-66.4), PFS was 40.1% (95% CI:28.1-54.5), and LRC was 66.7% (95% CI:51.5-78.8). We analyzed some immune and inflammatory prognostic factors such as pre-RT platelet count, hemoglobin, lymphocyte ratio in white blood cell (WBC), platelet-to-lymphocyte ratio (PLR) or a neutrophil-to-lymphocyte ratio (NLR) or total lymphocyte count (TLC).In univariate analysis, lower lymphocyte ratio was significantly associated with worse PFS (P = 0.0446, Hazard radio: 1.90, 95% CI: 1.02-3.58). There was not significantly different between the median value of the baseline PLR, NLR, TLC, and Platelet. In univariate analysis, age ≥ 75, N+, and chemotherapy after RT were significantly associated with poor OS. In multivariate analysis, age ≥ 75 years was significantly correlated with OS. There were no patients developed severe acute toxicity (≥ Grade 3). Among late toxicity events, 2 patients (3.38%) were suspected of radiation-induced liver disease. To our knowledge, this is the first report to analyze the immune and inflammatory prognostic factor of postoperative radiation therapy in patients for CCA. Lymphocyte ratio before the RT was the immune and inflammatory prognostic factor for postoperative radiation therapy in patients for CCA.