Clear differences in ovarian cancer incidence and trends by ethnicity among Asian Americans.

Background: Across major races in the United States (U.S.), ovarian cancer incidence is low among Asian American women. However, this observation aggregates Asian Americans as a single group despite their heterogeneity. Disaggregating the ethnic Asian population will produce more useful information to better understand ovarian cancer incidence among Asian women in the U.S.

Methods: Data from the Surveillance, Epidemiology, and End Results Program from 1990 to 2014 were used to compare age-adjusted incidence rates (AAIRs, per 100,000 women) for ovarian cancer for the six largest U.S. Asian ethnicities (Asian Indian/Pakistani, Chinese, Filipino, Japanese, Korean, Vietnamese) to non-Hispanic whites (NHWs). The race/ethnicity-specific AAIRs were calculated by time period and histotype. We examined the magnitude and direction of AAIR trends using average annual percent change (AAPC) statistics.

Results: All Asian ethnicities had significantly lower ovarian cancer incidence rates than NHWs. However, among Asian ethnicities, Asian Indians/Pakistanis had the highest rate of ovarian cancer (AAIR = 10.51, 95% CI: 9.65-11.42) while Koreans had the lowest (AAIR = 7.23, 95% CI: 6.62-7.88). Clear cell ovarian cancer had significantly higher incidence rates among Chinese, Filipino, and Japanese women than NHW women (incidence rate ratio (IRR) = 1.49, 95% CI: 1.29-1.72, IRR = 1.30, 95% CI: 1.12-1.51, IRR = 1.64, 95% CI: 1.36-1.97, respectively). Incidence trends also differed by Asian ethnicity with significant decreases only observed for Chinese (AAPC = -1.49, 95% CI: -2.22 to -0.74) and Japanese (AAPC = -1.75, 95% CI: -2.57 to -0.92).

Conclusions: Examining Asian Americans as a single group results in missed ethnic-specific disparities in ovarian cancer, hence disaggregating this heterogeneous population in future research is warranted.