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