Trends in Primary Gallbladder Cancer Incidence and Incidence-based Mortality in the United States, 1973 to 2015

Objectives: Primary gallbladder cancer (GBC) is the most common biliary tract cancer with poor survival despite aggressive treatment. This study aimed to investigate the trends of GBC incidence and incidence-based mortality (IBM) over the last 4 decades. Materials and Methods: GBC cases diagnosed between 1973 and 2015 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Incidence rates, IBM rates, and annual percent changes (APCs) were calculated and stratified according to population and tumor characteristics. Results: The cohort consisted of 10,792 predominantly white (81%) and female (71%) GBC patients. The overall GBC incidence decreased by 1.65% (95% confidence interval [CI]: 1.45% to 1.84%) per year since 1973, but has plateaued since 2002. IBM decreased by 1.69% (95% CI: 1.22% to 2.16%) per year from 1980 to 2015; the rate of decrease in IBM rates was lower during 1997 to 2015 (APC: −1.19%, 95% CI: −1.68% to −0.71%) compared with 1980 to 1997 (APC: −3.13%, 95% CI: −3.68% to −2.58%). Conclusions: The incidence and IBM rates of GBC have been decreasing over the last 40 years, but the decrease plateaued over the last 2 decades. The effects of treatment modalities, including laparoscopic cholecystectomy, adjuvant chemotherapy, and radiation on the incidence and IBM of GBC need to be further investigated.