Treatment Sequencing and Independent Outcomes of First- and Second-Line Chemotherapy in a Retrospective Series of Patients with Biliary Tract Cancer

<b>Background/Objectives:</b> Biliary tract cancers (BTCs) are aggressive neoplasms with limited therapeutic options. The amount of prospective evidence is poor, and limited data are available on the impact of treatment sequencing on survival. Here we report a real-world experience of patients with advanced BTC treated with at least three lines of therapy. We evaluated the impact of sequential treatments, and we further compared the efficacy of Gemcitabine/Cisplatin (GemCis) and mFOLFOX to other first- and second-line chemotherapy regimens, respectively. <b>Methods</b>: Data on 60 patients with locally advanced or metastatic BTC under the care of a single Italian referral hospital and treated with at least three lines of chemotherapy were retrospectively collected. Data from 56 patients were included in the analysis. Survival analyses were performed using R software (v1.2.5042). <b>Results</b>: We compared the outcomes of patients treated according to the "standard" pre-immunotherapy sequence (GemCis and mFOLFOX in the first and second lines, respectively) versus those treated with all other combinations ("control" group). Our analysis did not show significant survival differences between the two groups. However, it should be noted that we selected long-survival patients by including only those who received at least three or more lines of chemotherapy. Focusing on the first-line setting, no significant differences in both mPFS and mOS emerged by comparing GemCis versus other doublets (mainly Gemcitabine/Oxaliplatin). Similarly, mPFS and mOS from second-line treatment did not statistically differ between patients treated with mFOLFOX versus those treated with other regimens (71% chemotherapy doublets). <b>Conclusions:</b> Our series provides real-world outcomes of patients with advanced BTC before the approval of immunotherapy. Even considering the monocentric and retrospective design, our study represents one of the first analyses on the impact of sequential treatment strategies in patients with BTC.