Prognostic stratification of patients with biliary tract cancer treated with chemoimmunotherapy: A retrospective multicenter real‐world study

Background: The objective of this study is to explore and validate a novel prognostic index for patients with locally advanced or metastatic biliary tract cancer (BTC) treated with first-line therapy with cisplatin, gemcitabine, and durvalumab. Methods: This is a retrospective, multicenter, real-world study including 712 patients in the training cohort and 646 patients in the validation cohort. Using multivariate analysis for overall survival (OS) and applying the adjustment methods of Holm-Bonferroni, Benjamini-Hochberg, and Hommel, the authors identified five baseline statistically significant variables: disease stage, neutrophils, carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA 19-9) levels, and Eastern Cooperative Oncology Group performance status (ECOG PS). According to the HR of each variable, β coefficients were calculated and the following formula was applied: (0.1757 * neutrophils value) + (0.5055 * ECOG PS) + (1.4037 * disease stage) + (0.1108 * CA 19-9) + (0.2126 * CEA). According to tertiles, the authors developed a prognostic model called the SENECA index, dividing the population into three risk groups: low-risk (≤2.14), intermediate-risk (2.15–2.89), and high-risk (>2.89). Results: Median OS was 23.4 months in low-risk group,16.1 months in intermediate-risk group, and 8.3 months in high-risk group (low-risk hazard ratio [HR], 0.20; intermediate-risk HR, 0.36; high-risk HR, 1; p <.0001). Median progression-free survival was 11.0 months in low-risk group (33.1%), 8.8 months in intermediate-risk group (33.3%), and 5.5 months in high-risk group (33.5%) (low-risk HR, 0.35; intermediate-risk HR, 0.55; and high-risk HR, 1; p <.0001). Conclusions: The SENECA index is a practical instrument for prognostic stratification of patients with BTC receiving chemoimmunotherapy.