Second-line chemotherapy in advanced biliary cancer: the present now will later be past

We have read with great interest the recent paper by Lamarca et al. [1], in which the authors conducted a systematic review of the literature to evaluate the level of evidence behind the use of second-line chemotherapy for patients with advanced biliary tract cancer (aBTC). The authors collected data of 761 patients from 14 phase II trials and 9 retrospective analyses, reporting a mean overall survival (OS) of 7.2 months and a mean progres- sion-free survival (PFS) of 3.2 months. Response rate and disease control rate (DCR) were 7.7% and 49.5%, respectively, suggesting that a cohort of aBTC patients may benefit from second-line chemotherapy. We really thank the authors for their efforts: due to the paucity of reliable data in this setting, the topic is of great interest. In order to further reduce the impact of study heterogeneity on the results, we suggest to the authors to exclude the reports of targeted agents and limit the analyses to chemotherapy only: this could be particularly important when alternative end points (such as PFS) are being investigated as surrogate for OS in pooled series.