To assess the associations between depot medroxyprogesterone acetate (DMPA) and endometrial cancer.
This multicenter case–control study was conducted among tertiary hospitals in Thailand. Patients were women with endometrial cancer. Controls were women admitted for other conditions, matched for age within 5 years of the patients' age. The controls had to have no abnormal vaginal bleeding, history of hysterectomy, or cancers of the other organs. A standardized questionnaire was used to gather information. Conditional logistic regression was applied to calculate adjusted odds ratio (aORs) and 95% confidence intervals (CIs).
During 2015 to 2021, 378 patients and 1134 controls were included. Ever use of DMPA was associated with a 70% decreased overall risk of endometrial cancer (aOR, 0.30 [95% CI, 0.21–0.42]). Endometrial cancer risk declined by 3% (aOR, 0.97 [95% CI, 0.96–0.98]) for every 3 months of DMPA use. The magnitude of the decline in endometrial cancer risk did not vary appreciably by cancer subtypes (aOR, 0.26 [95% CI, 0.17–0.41] and 0.38 [95% CI, 0.22–0.65] for low‐grade and high‐grade tumors, respectively).
Depot medroxyprogesterone acetate use was inversely associated with endometrial cancer risk in a duration‐dependent manner. This association was independent of cancer subtype.