Rapid increase in endometrial cancer incidence and ethnic differences in New Zealand.

PURPOSE: Endometrial cancer accounts for 3.9% of all female cancers globally, and its incidence appears to be increasing in women under 40 years of age. This paper investigated ethnic-specific trends in endometrial cancer across different age groups in New Zealand. METHODS: Women who were diagnosed with endometrial cancer between 1996 and 2012 were identified from the New Zealand Cancer Registry. Annual age-standardized incidence and mortality rates were calculated for each ethnicity (Māori, Pacific, and non-Māori non-Pacific) in four age groups (< 40, 40-49, 50-74, and 75 +). The estimates were adjusted for hysterectomy. Joinpoint regression analysis was used to assess trends over time and annual percentage changes (APCs) were estimated. RESULTS: Between 1996 and 2012, age-standardized incidence rates increased in all women and significantly in the < 40, 40-49, and 50-74 age groups (APC 9.22, 3.56, and 1.65 respectively). Incidence rates were highest in Pacific women and increased most rapidly in those under 50 years of age (APC 9.36). Conversely, age-standardized mortality rates decreased in all women and significantly in the 50-74 and 75 + age groups (APC - 5.25 and - 5.06 respectively), with the highest rate observed in Pacific women. CONCLUSION: Pacific women had the highest incidence of endometrial cancer and the trend was increasing, particularly in young women. This could be attributed, at least in part, to a high and increasing rate of obesity in these women and should be explored in future research.