Conditional Recurrence-Free Survival after Oncologic Extended Resection for Gallbladder Cancer: An International Multicenter Analysis.

BACKGROUND: Data to guide surveillance following oncologic extended resection (OER) for gallbladder cancer (GBC) are lacking. Conditional recurrence-free survival (C-RFS) can inform surveillance. We aimed to estimate C-RFS and identify factors affecting conditional RFS after OER for GBC. PATIENTS AND METHODS: Patients with ≥ T1b GBC who underwent curative-intent surgery in 2000-2018 at four countries were identified. Risk factors for recurrence and RFS were evaluated at initial resection in all patients and at 12 and 24 months after resection in patients remaining recurrence-free. RESULTS: Of the 1071 patients who underwent OER, 484 met the inclusion criteria; 290 (60%) were recurrence-free at 12 months, and 199 (41%) were recurrence-free at 24 months. Median follow-up was 24.5 months for all patients and 47.21 months in survivors at analysis. Five-year RFS rates were 47% for the overall population, 71% for patients recurrence-free at 12 months, and 87% for the patients without recurrence at 24 months. In the entire cohort, the risk of recurrence peaked at 8 months. T3-T4 disease was independently associated with recurrence in all groups: entire cohort [hazard ratio (HR) 2.16, 95% confidence interval (CI) 1.49-3.13, P < 0.001], 12-month recurrence-free (HR 3.42, 95% CI 1.88-6.23, P < 0.001), and 24-month recurrence-free (HR 2.71, 95% CI 1.11-6.62, P = 0.029). Of the 125 patients without these risk factors, only 2 had recurrence after 36 months. CONCLUSION: C-RFS improves over time, and only T3-T4 disease remains a risk factor for recurrence at 24 months after OER for GBC. For all recurrence-free survivors after 36 months, the probability of recurrence is similar regardless of T category or disease stage.