Gallbladder carcinoma: a New Zealand centre's 10-year experience with presentation, ethnic diversity and survival rate

Background Gallbladder cancer is a high‐mortality cancer with a wide range of incidence worldwide. Some indigenous populations are known to have a higher incidence of gallbladder cancer. Commonly, it is incidentally discovered during routine gallbladder surgery. The primary aim was to determine the incidence and characteristics of gallbladder cancer in a New Zealand population. The secondary aim was to determine if inequalities in gallbladder cancer rates between Māori and non‐Māori have decreased. Methods A retrospective cohort study utilizing an online database was conducted to identify all patients with gallbladder malignancy treated in the Waitemata District Health Board from 2003 to 2013. The outcomes measured were staging of cancer, histology, ethnicity, incidental finding and survival rates. Results The age‐standardized incidence (ASI) rate of gallbladder carcinoma is 0.60/100 000. The gender‐specific ASI rates were 0.21/100 000 (men) and 0.76/100 000 (women). The incidence for Māori was 0.96/100 000 (men) and 1.37/100 000 (women). Gallbladder carcinoma was found incidentally in 0.44% of cholecystectomies, which made up 46.2% of all cases. Right upper quadrant pain was the most common presenting symptom (74.4%). Surgery was the most common treatment modality (66.7%). Mean survival across all patients was 12.24 months. Conclusion Our study found that the ASI of gallbladder carcinoma when compared with the Koea et al. study has decreased for men from New Zealand, but appears to have increased slightly for women from New Zealand. The raw incidence for Māori men and women appears to have decreased, but inequality in gallbladder cancer incidence between Māori and non‐Māori remains.