One common and unpleasant consequence of menopause and hormonal breast cancer treatments (anti-estrogen therapies, meaning tamoxifen and the AIs) is often vaginal dryness. There are many over the counter products that help, but some women are so uncomfortable that they prefer to use vaginal estrogens. There has long been a controversy about the absolute safety of these preparations for women who have ER positive breast cancers. It has been known that a small amount of estrogen is absorbed, but it is unclear whether this is a real risk. For years, the advice has been "talk to your doctor" and make an individual decision.
A recent report at the San Antonio meetings gives us more information:
SABCS: Risk of Vaginal Estrogens Not Known in Breast Cancer Patients
SAN ANTONIO -- Postmenopausal breast cancer patients face an uncertain risk from use of vaginal estrogen preparations that raise systemic estradiol levels, data from a small clinical study suggested. Both a vaginal estradiol ring and vaginal estradiol tablets significantly increased serum estradiol levels, researchers reported here. Estradiol levels remained elevated throughout the three months of the ring's therapeutic life, while tablets caused spikes in estradiol levels that persisted for 12 to 24 hours after twiceweekly insertion.
"We know that there is absorption with both the tablet and the ring," Shannon Wills, PhD, of William Beaumont Hospital in Royal Oak, Mich., said in an interview at the San Antonio Breast Cancer Symposium. "We do not know if there is any clinical significance. We do not know if that increases their chances of breast cancer or regeneration of the tumor. We just know that there is absorption."
Atrophic vaginitis is a common consequence of menopause and can have a substantial adverse impact on quality of life. Many postmenopausal women use vaginal estrogens to alleviate associated symptoms, including vaginal dryness, pain, dyspareunia, and urinary and sexual dysfunction. Systemic absorption of estradiol by postmenopausal breast cancer patients receiving adjuvant endocrine therapy had not been studied extensively, said Wills. To that end, she and colleagues in Michigan and London conducted a prospective, case-control study.
The study included 24 postmenopausal breast cancer patients who had been treated with an aromatase inhibitor or selective estrogen receptor modifier (SERM) and were using vaginal estrogens to treat symptoms of atrophic vaginitis. Ten patients used a vaginal ring that was replaced every 90 days, and 14 patients used estradiol tablets inserted twice weekly.
For comparison, the investigators recruited 24 postmenopausal breast cancer patients who were being treated with an aromatase inhibitor or SERM but were not using vaginal estrogens. Serum estradiol levels were measured prior to ring insertion and 30 and 60 days afterward, or the morning prior to tablet insertion and 12 hours after insertion. Serum samples also were obtained from the control patients, all of whom had taken an aromatase inhibitor or SERM for more than 14 days.
The mean age of the patients in the vaginal preparation group was 60 (compared with 68 in the control group), and they had used vaginal estrogens for an average of 20 months prior to enrollment. Among the patients using estradiol tablets, preinsertion serum estradiol levels were an average of 4.7 pmol/L greater than those of the control group, a nonsignificant difference. However, 12 hours after tablet insertion, the patients' mean estradiol levels were 76 pmol/L greater than baseline levels (P<0.0001).
One patient using the tablets had estradiol assessments preinsertion and at 12 and 24 hours. Her serum estradiol level had returned to the baseline level by 24 hours. Women using vaginal rings had significantly higher preinsertion serum levels of estradiol compared with the< control group (+14.2 pmol/L, P=0.0001). Eight weeks postinsertion, mean serum estradiol level had increased by more than 30 pmol/L compared with baseline levels (P<0.001). Two patients had no increase in serum estradiol levels 60 days after ring insertion.
Wills S, et al "The effects of vaginal estrogens on serum estradiol levelsl in postmenopausal breast cancer survivors receiving an aromatase inhibitor or a selective estrogen receptor modulator (SERM)" SABCS 2009; Abstract 806.