Supplementary Material for: Prognostic impact of inflammation-based scores for extrahepatic cholangiocarcinoma

Introduction: Although the relationship between systemic inflammatory responses and prognosis has been known in various cancers, it remains unclear which scores are most valuable for determining the prognosis of extrahepatic cholangiocarcinoma. We aimed to verify the usefulness of various inflammation-based scores as prognostic factors in patients with resected extrahepatic cholangiocarcinoma. Methods: We analyzed consecutive patients undergoing surgical resection for extrahepatic cholangiocarcinoma at our institution between January 2000 and December 2019. The usefulness of the following inflammation-based scores as prognostic factor was investigated: Glasgow prognostic score (GPS), modified Glasgow prognostic score (mGPS), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), lymphocyte to monocyte ratio (LMR), prognostic nutrition index (PNI), C-reactive protein to albumin ratio (CAR), controlling nutritional status (CONUT), and prognostic index (PI). Results: A total of 169 patients were enrolled in this study. Of the nine scores, CAR and CONUT indicated prognostic value. Furthermore, multivariate analysis for overall survival revealed that high CAR (>0.23) was an independent prognostic factor (HR: 1.816, 95%CI: 1.135-2.906, p=0.0129), along with lymph node metastasis and curability. There was no difference in tumor staging and short-term outcomes between the low CAR (≤ 0.23) and high CAR groups. Conclusions: CAR was the most valuable prognostic score in patients with resected extrahepatic cholangiocarcinoma.