Simple cholecystectomy is an adequate treatment for grade I T1bN0M0 gallbladder carcinoma: Evidence from 528 patients

BACKGROUND: T1b gallbladder carcinoma (GBC) is defined as a tumor that invades the perimuscular connective tissue without extension beyond the serosa or into the liver. However, controversy still exists over whether patients with T1b GBC should undergo cholecystectomy alone or radical GBC resection. AIM: To explore the optimal surgical approach in patients with T1b gallbladder cancer of different pathological grades. METHODS: Patients with T1bN0M0 GBC who underwent surgical treatment between 2000 and 2017 were included in the Surveillance, Epidemiology, and End Results database. The Kaplan-Meier method and log-rank test were used to analyze the overall survival (OS) and disease-specific survival (DSS) of patients with T1b GBC of different pathological grades. Cox regression analysis was used to identify independent predictors of mortality and explore the selection of surgical methods in patients with T1b GBC of different pathological grades and their relationship with prognosis. RESULTS: Of the 528 patients diagnosed with T1bN0M0 GBC, 346 underwent simple cholecystectomy (SC) (65.5%), 131 underwent SC with lymph node resection (SC + LN) (24.8%), and 51 underwent radical cholecystectomy (RC) (9.7%). Without considering the pathological grade, both the OS (P < 0.001) and DSS (P = 0.003) of T1b GBC patients who underwent SC (10-year OS: 27.8%, 10-year DSS: 55.1%) alone were significantly lower than those of patients who underwent SC + LN (10-year OS: 35.5%, 10-year DSS: 66.3%) or RC (10-year OS: 50.3%, 10-year DSS: 75.9%). Analysis of T1b GBC according to pathological classification revealed no significant difference in OS and DSS between different types of procedures in patients with grade I T1b GBC. In patients with grade II T1b GBC, obvious survival improvement was observed in the OS (P = 0.002) and DSS (P = 0.039) of those who underwent SC + LN (10-year OS: 34.6%, 10-year DSS: 61.3%) or RC (10-year OS: 50.5%, 10-year DSS: 78.8%) compared with those who received SC (10-year OS: 28.1%, 10-year DSS: 58.3%). Among patients with grade III or IV T1b GBC, SC + LN (10-year OS: 48.5%, 10-year DSS: 72.2%), and RC (10-year OS: 80%, 10-year DSS: 80%) benefited OS (P = 0.005) and DSS (P = 0.009) far more than SC (10-year OS: 20.1%, 10-year DSS: 38.1%) alone. CONCLUSION: Simple cholecystectomy may be an adequate treatment for grade I T1b GBC, whereas more extensive surgery is optimal for grades II-IV T1b GBC.