Uterine cancer incidence trends and 5-year relative survival by race/ethnicity and histology among women under 50 years.

backgroundUterine cancers diagnosed before age 50 years are increasing in the U.S., but changes in clinical characteristics and survival over time across racial/ethnic groups have not been previously described.

objectiveTo investigate age-adjusted, hysterectomy corrected incidence rates and trends, and 5-year relative survival rates of uterine cancer in women aged <50 years, overall and stratified by race/ethnicity and histology. STUDY

designWe included microscopically confirmed uterine cancer cases (diagnosed 2000-2019) in women aged 20 to 49 years from the Surveillance, Epidemiology, and End Results Program. Age-adjusted incidence and 5-year relative survival rates, and 95% confidence intervals were computed using Surveillance, Epidemiology, and End Results (SEER) ∗Stat and compared across time periods (2000-2009 and 2010-2019). Incidence rates were adjusted for hysterectomy prevalence using Behavioral Risk Factor Surveillance System data, and trends were computed using the Joinpoint regression program.

resultsWe included 57,128 uterine cancer cases. The incidence of uterine cancer increased from 10.1 per 100,000 in 2000-2009 to 12.0 per 100,000 in 2010-2019, increasing at an annual rate of 1.7%/y for the entire period. Rising trends were more pronounced among women <40 years (3.0%/y and 3.3%/y in 20-29 and 30-39 years, respectively) than in those 40 to 49 years (1.3%/y), and among underrepresented racial/ethnic groups (Hispanic 2.8%/y, non-Hispanic-Black 2.7%, non-Hispanic-Asian/Pacific Islander 2.1%) than in non-Hispanic-White (0.9%/y). Recent (2010-2019) incidence rates were highest for endometrioid (9.6 per 100,000), followed by sarcomas (1.2), and nonendometrioid subtypes (0.9). Rates increased significantly for endometrioid subtypes at 1.9%/y from 2000 to 2019. Recent endometrioid and nonendometrioid rates were highest in non-Hispanic-Native American/Alaska Native (15.2 and 1.4 per 100,000), followed by Hispanic (10.9 and 1.0), non-Hispanic-Asian/Pacific Islander (10.2 and 0.9), non-Hispanic-White (9.4 and 0.8), and lowest in non-Hispanic-Black women (6.4 and 0.8). Sarcoma rates were highest in non-Hispanic-Black women (1.8 per 100,000). The 5-year relative survival remained unchanged over time for women with endometrioid (from 93.4% in 2000-2009 to 93.9% in 2010-2019, P≥.05) and nonendometrioid subtypes (from 73.2% to 73.2%, P≥.05) but decreased for women with sarcoma from 69.8% (2000-2009) to 66.4% (2010-2019, P<.05).

conclusionUterine cancer incidence rates in women <50 years have increased from 2000 to 2019 while survival has remained relatively unchanged. Incidence trends can be primarily attributed to increasing rates of cancers with endometrioid histology, with the greatest increases observed among non-Hispanic-Black, Hispanic, and non-Hispanic-Asian/Pacific Islander. Sarcomas, while much rarer, were the second most common type of uterine cancer among women <50 years and have poor prognosis and apparent decreasing survival over time. Rising rates of uterine cancer and the distinct epidemiologic patterns among women <50 years highlight the need for effective prevention and early detection strategies for uterine cancer in this age group.