Recent changes in endometrial cancer trends among menopausal-age US women

Background: Changes in endometrial cancer incidence rates after the precipitous decline in menopausal hormone therapy (MHT) use in 2002 have not been evaluated. Methods: Using data from the Surveillance, Epidemiology, and End Results Program from 1992 to 2009 (SEER 13), we identified 63. 428 incident endometrial cancer cases among women ages 20-74. We compared annual percent change (APC) in endometrial cancer incidence rates from 1992 to 2002 to rates from 2003 to 2009. Results: In contrast to the constant endometrial cancer rate pattern observed from 1992 to 2002 (APC 0.0%), rates increased after 2002 in women 50-74 years old (2.5%; P_{APC comparison}<0.01). Endometrial cancer incidence increased over the entire time period among women ages 20-49 (1992-2002: 1.1%; 2003-2009: 2.1%; P_{APC comparison}=0.21). Post-2002 increases in incidence among women ages 50-74 were specific to Type I endometrial tumors (1992-2002: -0.6%; 2003-2009: 1.6%; P_{APC comparison}<0.01). Discussion: The increase in endometrial cancer incidence rates after 2002 may be related to the widespread decrease in estrogen plus progestin MHT use, which has been reported to lower endometrial cancer risk in overweight and obese women.