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

Background: 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.
Methods: 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.
Results: 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).
Conclusions: 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.
(© 2016 American Cancer Society.)