Real-world experience supporting the role of oncologic resection and adjuvant chemotherapy in biliary tract cancers

Background: Complete resection followed by adjuvant chemotherapy is the gold standard for patients with localized cholangiocarcinoma (CC) or gallbladder cancer (GBC). However, this is not always feasible, and recurrence rates remain high.Objectives: To understand the real-world proportions and reason for treatment failure in resected biliary tract cancers.Design and methods: We performed a retrospective population-based review of patients with GBC or CC [intrahepatic (IHCC) or extrahepatic (EHCC)] resected between 2005 and 2019 using the BC Cancer provincial database. A chart review was conducted to characterize demographics, treatments received and outcomes.Results: In total, 594 patients were identified of whom 416 (70%) had disease recurrence. Most GBCs (96%) were diagnosed incidentally, and repeat oncologic resection was performed in 45%. Adjuvant chemotherapy was received in 51% of patients diagnosed after 2017 (mostly capecitabine). Patient co-morbidities, disease progression and patient preference were the commonest reasons for not proceeding with adjuvant chemotherapy. One-third of patients did not complete all planned cycles. Median overall survival was significantly higher in those with complete (R0) versus incomplete (R1) resection [31.6 versus 18 months, hazard ratio (HR): 0.43, 95% confidence interval (CI): 0.35-0.53] and in those with versus without re-resection for GBC [29.4 versus 19 months, HR: 0.55, 95% CI: 0.41-0.73]. There was a trend towards improved survival with versus without adjuvant therapy (HR: 0.79, 95% CI: 0.61-1.02). Only 25% in the more contemporary cohort (2017-2019) had an R0 resection and completed adjuvant chemotherapy.Conclusion: Complete resection, including reresection for incidentally diagnosed GBCs, and adjuvant chemotherapy were associated with improved outcomes in this retrospective cohort, yet many patients were not able to complete these treatments. Neoadjuvant strategies may improve treatment delivery and ultimately, outcomes.