SAN FRANCISCO – The use of unopposed topical vaginal estrogen is not associated with an increased risk of endometrial hyperplasia or cancer, findings from a large database review suggest.
Yearly disease incidence between 2006 and 2012 among women aged 46 years or older from the Kaiser Permanente Northern California membership database did not differ significantly by number of dispensed vaginal estrogen prescriptions over a 3-year period, Dr. Kathryn M. Gunnison reported at the annual meeting of the American College of Obstetricians and Gynecologists.
Yearly incidence per 10,000 women was 1.86-18.23 in those who received four or more prescriptions, 7.29-15.01 in those who received one to three prescriptions, and 8.74-10.86 in those who received no prescriptions, said Dr. Gunnison of Kaiser Permanente Medical Center, Santa Clara, Calif.
The overall incidence rates in the groups, respectively, were 9.96, 10.25, and 9.96 per 10,000 women, she said.
Dr. Gunnison and her colleagues used ICD-9 codes and the Kaiser Permanente Northern California Cancer Registry to identify the first date of endometrial hyperplasia or cancer in the yearly population, and pharmacy records were reviewed to identify dispensed vaginal estrogen prescriptions in the 3 years prior to diagnosis of endometrial hyperplasia or cancer; those exposed within 2 years prior to diagnosis were excluded, as were those who used systemic estrogen.
Between 450,000 and 530,000 women met the selection criteria for each year during the study period, and the use of vaginal estrogen increased slightly over the study period. Between 26,000 and 34,000 women filled one to three prescriptions during the study years, and between 9,300 and 23,000 filled four or more prescriptions.
The overall annual incidence of endometrial hyperplasia or cancer increased over the study period, which is consistent with national data. The incidence rose from 8.96 per 10,000 women in 2006 to 10.56 per 10,000 women in 2012, but did not differ significantly by number of prescriptions filled.
“So we think our data suggest that the use of unopposed topical vaginal estrogen is not associated with an increased risk for endometrial hyperplasia or cancer over a 3-year period. However, further studies are needed,” Dr. Gunnison said, noting that the current study is limited by the retrospective, descriptive study design, and by the fact that the estrogen delivery method was not examined. The study also did not control for potential confounders.
Despite these limitations, it is the first study to look at vaginal estrogen use for more than 1 year, she said.
The findings are encouraging, she said, since many women choose low-dose topical vaginal estrogen because of concerns about potential adverse effects from systemic estrogen.
Dr. Gunnison reported having no financial disclosures.