Prognostic Role of a New Index Tested in European and Korean Advanced Biliary Tract Cancer Patients: the PECS Index

Background and Aim: The aim of the present study is to evaluate a new index (PECS (PsECogSii)index) influenced by PS ECOG and systemic immune-inflammation index (SII) in unresectable locally advanced or metastatic BTC patients treated with first-line chemotherapy. Methods: This multicenter, international, study was conducted on a training cohort of 130 patients and in three European and Korean validation cohorts The PECS index was calculated as ECOG × SII index (neutrophil count × platelet count/lymphocyte count). Event-time distributions were estimated using the Kaplan–Meier method and survival curves were compared using the log-rank test. Results: In the training cohort, the median overall survival (mOS) was 13.2 months, 8.7 months, and 3.8 months for patients with PECS-0, PECS-1, and PECS-2, respectively (PECS-0: HR = 1; PECS-1: HR 1.41; PECS-2: HR 3.23) (p < 0.0001). In the first validation cohort, the mOS was 12.8 months, 10.1 months, and 5.3 months for patients with PECS-0, PECS-1, and PECS-2, respectively (PECS-0: HR = 1; PECS-1: HR 1.29; PECS-2: HR 2.40) (p < 0.0001). In the second validation cohort, the mOS was 21.2 months, 10.2 months, and 3.0 months for patients with PECS-0, PECS-1, and PECS-2, respectively (PECS-0: HR = 1; PECS-1: HR 2.25; PECS-2: HR 9.00) (p < 0.0001). In the third validation cohort, the median OS was 15.5 months, 7.5 months, and 3.7 months for patients with PECS-0, PECS-1, and PECS-2, respectively (PECS-0: ref HR = 1; PECS-1: HR 2.14; PECS-2: HR 5.00) (p < 0.0001). Multivariate analysis in all cohorts confirmed the PECS index as an independent prognostic factor for OS. Conclusions: The easy assessment, low cost, and reproducibility make PECS index a promising tool to assess the prognosis of BTC patients in future clinical practice.