Prognostic Nutritional Index Associates with Immunotherapy Response in Patients with Metastatic Biliary Tract Cancer.

Purpose: The present study aims to evaluate the effect of prognostic nutrition index (PNI) on the response and prognosis of patients with metastatic biliary tract cancer (BTC) patients treated with immunotherapy.Methods: The outcomes of 83 patients with metastatic BTC were evaluated retrospectively. Among them, 51 received immune checkpoint inhibitors (ICIs) treatment (ICIs cohort) and 32 patients received first-line chemotherapy (chemotherapy cohort). According to the optimal cutoff value of PNI, patients in ICIs cohort were divided into low PNI group (PNI < 44.30) and high PNI group (PNI≥ 44.30).Results: Patients received first-line immunotherapy-based combination antitumor therapy in ICIs cohort showed significant longer median PFS and OS contrast with first-line chemotherapy cohort. In ICIs cohort, median PFS and OS were significantly longer in the high PNI group. In addition, multivariate Cox regression analysis showed that high PNI was an independent risk factor for median PFS (hazard ratio (HR), 0.474, 95% CI, 0.246-0.910; P = 0.025) and median OS (HR, 0.229, 95% CI, 0.097-0.539; P = 0.001) in ICIs cohort, respectively. Conclusion: Our study provides preliminary evidence that immunotherapy for metastatic BTC is effective and safe. PNI was an independent prognostic indicator of median PFS and OS in patients with metastatic BTC receiving immunotherapy.