Trends of uterine carcinosarcoma in the United States

OBJECTIVE Uterine carcinosarcoma (UCS) is a rare type of high-grade endometrial cancer (EC) that has been understudied with population-based statistics due to its rarity. This study examined temporal trends in the proportion of UCS among women with EC. METHODS This is a retrospective observational study examining The Surveillance, Epidemiology, and End Results program between 1973-2013. Primary EC cases were eligible for analysis, and a time-specific proportion of UCS was examined during the study period. RESULTS UCS was seen in 11,000 (4.7%) women among 235,849 primary EC cases. Mean age at UCS diagnosis increased from 65.9 to 71.7 years between 1973-1989 and then decreased from 71.7 to 67.0 years between 1989-2013 (both, p<0.001). Proportion of Black women significantly increased during the study period (11.9%-20.0%, p<0.001), whereas the proportion of White women decreased from 86.0% to 60.5% between 1987-2013 (p<0.001). There was a significant increase in the proportion of UCS among primary EC from 1.7% to 5.6% between 1973-2013 (p<0.001). Among type II ECs (n=76,118), the proportion of UCS also increased significantly from 6.0% to 17.5% between 1973-2013 (p<0.001). An increasing proportion of UCS was seen in both young and older women but the magnitude of interval increase was larger in the older age group between 1973-2013 (<60 years, from 1.3% to 3.3%. p<0.001; and ≥60 years, from 2.6% to 7.0%, p<0.001). CONCLUSION Our study demonstrated that the proportion of UCS has significantly increased among EC, accounting for more than 5% in recent years.