Increased incidence but improved median overall survival for biliary tract cancers diagnosed in Ontario from 1994 through 2012: A population-based study.

Abstract

To the authors' knowledge, the incidence of biliary tract cancer (BTC) in Canada is unknown. In the current study, the authors sought to describe the epidemiology of BTC using a large population-based cancer database from Ontario, Canada. The current study was a population-based cohort study using the Ontario Cancer Registry. Patients with intrahepatic cholangiocarcinoma (IHCC), extrahepatic cholangiocarcinoma (EHCC), and gallbladder cancer (GBC) diagnosed between 1994 and 2012 were included. Age-standardized incidence and mortality rates were compared using incidence rate ratios (IRRs). Overall survival from the time of diagnosis was calculated for 3 eras: 1994 through 1999, 2000 through 2005, and 2006 through 2012. The number of patients receiving chemotherapy, radiotherapy, or surgery was determined using linked clinical data. A total of 9039 cases (1569 IHCC cases, 4337 EHCC cases, and 3133 GBC cases) were identified. The rate of BTC increased by 1.6% per year (IRR, 1.016; 95% confidence interval [95% CI], 1.008-1.024 [P<.001]). The incidence increased by 7.0% per year among cases of IHCC (IRR, 1.070; 95% CI, 1.058-1.081 [P<.001]) and 1.8% per year in cases of EHCC (IRR, 1.018; 95% CI, 1.009-1.027 [P<.001]), whereas the incidence of GBC remained unchanged (IRR, 0.991; 95% CI, 0.982-1.001 [P = .086]). The median survival for the cohort was 8.3 months, with improvement noted over the study period (6.1 months for 1994-1999 vs 8.5 months for 2000-2005 vs 10.3 months for 2006-2012 [P<.001]). The median survival was the longest for EHCC (11.3 months), followed by GBC (6.4 months) and IHCC (6.2 months). The percentage of patients receiving chemotherapy and/or radiotherapy increased over the study (P<.001), whereas the percentage of patients receiving surgery decreased (P<.001). An increased incidence of BTC during 1994 through 2012 was observed. Explanations for the observed temporal improvement in median survival require further exploration. Cancer 2016;122:2534-43. © 2016 American Cancer Society.