Benefit of second-line systemic chemotherapy for advanced biliary tract cancer: A propensity score analysis

Abstract

Whether 2nd-line-chemotherapy (2LCTX)\u2009+\u2009best-supportive-care (BSC) benefits patients with advanced biliary tract cancer (aBTC) more than BSC alone is unclear. We therefore conducted a propensity-score-based comparative effectiveness analysis of overall survival (OS) outcomes in 80 patients with metastatic, recurrent, or inoperable aBTC, of whom 38 (48%) were treated with BSC\u2009+\u20092LCTX and 42 (52%) with BSC alone. After a median follow-up of 14.8 months and 49 deaths, the crude 6-, 12-, and 18-month Kaplan-Meier OS estimates were 77%, 53% and 23% in the BSC\u2009+\u20092LCTX group, and 29%, 21%, and 14% in patients in the BSC group (p\u2009=\u20090.0003; Hazard ratio (HR)\u2009=\u20090.36, 95%CI:0.20–0.64, p\u2009=\u20090.001). An inverse-probability-of-treatment-weighted (IPTW) analysis was conducted to rigorously account for the higher prevalence of favorable prognostic variables in the 2LCTX\u2009+\u2009BSC group. After IPTW-weighting, the favorable association between 2LCTX and OS prevailed (adjusted HR\u2009=\u20090.40, 95%CI: 0.17–0.95, p\u2009=\u20090.037). IPTW-weighted 6-, 12-, and 18-month OS estimates were 77%, 58% and 33% in the BSC\u2009+\u20092LCTX group, and 39%, 28% and 22% in the BSC group (p\u2009=\u20090.037). Moreover, the benefit of 2LCTX was consistent across several clinically-relevant subgroups. Within the limitations of an observational study, these findings support the concept that 2LCTX\u2009+\u2009BSC is associated with an OS benefit over BSC alone in aBTC.