Anatomic location of residual disease after initial cholecystectomy independently determines outcomes after re-resection for incidental gallbladder cancer

This study aimed to elucidate the impact of anatomic location of residual disease (RD) after initial cholecystectomy on survival following re-resection of incidental gallbladder cancer (IGBC). Patients with pT2 or pT3 gallbladder cancer (36 with IGBC and 171 with non-IGBC) who underwent resection were analyzed. Patients with IGBC were classified as follows according to the anatomic location of RD after initial cholecystectomy: no RD (group 1); RD in the gallbladder bed, stump of the cystic duct, and/or regional lymph nodes (group 2); and RD in the extrahepatic bile duct and/or distant sites (group 3). Timing of resection (IGBC vs. non-IGBC) did not affect survival in either multivariate or propensity score matching analysis. RD was found in 16 (44.4%) of the 36 patients with IGBC; R0 resection following re-resection was achieved in 32 patients (88.9%). Overall survival (OS) following re-resection was worse in group 3 (n = 7; 5-year OS, 14.3%) than in group 2 (n = 9; 5-year OS, 55.6%) (p = 0.035) or in group 1 (n = 20; 5-year OS, 88.7%) (p < 0.001). There was no survival difference between groups 1 and 2 (p = 0.256). Anatomic location of RD was independently associated with OS (group 2, HR 2.425, p = 0.223; group 3, HR 9.627, p = 0.024). The anatomic location of RD independently predicts survival following re-resection, which is effective for locoregional disease control in IGBC, similar to resection for non-IGBC. Not all patients with RD have poor survival following re-resection for IGBC.