A very small study found that vaginal rings or tablets that contain estradiol (a hormone related to estrogen) can increase blood levels of estradiol in postmenopausal women being treated for early-stage, hormone-receptor-positive breast cancer.
The research DIDN'T show that the higher estradiol levels increased the risk of the breast cancer coming back (recurrence). Still, estrogen and related hormones can make breast cancer cells develop and grow, so it's possible that vaginal preparations with estradiol in them could increase the risk of recurrence. These results were presented at the 2009 San Antonio Breast Cancer Symposium.
During and after menopause the lining of the vagina changes, which causes many women to have different levels of vaginal dryness. The condition, called atrophic vaginitis, is caused in part by lower amounts of estrogen in the body because of menopause. For some women, atrophic vaginitis can be particularly troublesome and cause a number of symptoms, including discomfort or pain during sexual intercourse (called dyspareunia).
Some women with atrophic vaginitis use some type of hormone replacement therapy (HRT) to help build up the vaginal lining and vaginal moisture. HRT taken as pills can help, but using HRT has been strongly associated with an increase in breast cancer and breast cancer recurrence.
One alternative to HRT pills is a vaginal estrogen preparation. These preparations come as a ring or a tablet that's inserted into the vagina so the estradiol is released directly onto the tissues it benefits. While the estradiol is meant to be confined to the vaginal area, this study shows that some of the estradiol is absorbed through the vaginal lining and gets into the blood stream.
In this study, 48 postmenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer were being treated with tamoxifen or an aromatase inhibitor after surgery and other breast cancer treatments. Half the women had been using a vaginal estradiol preparation for about 20 months to help ease atrophic vaginitis. Ten women used a vaginal ring, usually inserted every 90 days, and 14 women used a tablet, usually inserted twice per week. The other 24 women never used vaginal estradiol preparations. The researchers measured the blood levels of estradiol in all the women.
Women who used the vaginal estradiol tablet had estradiol blood levels that were slightly higher than the estradiol blood levels of women who never used a vaginal estradiol preparation right before the next tablet was to be inserted. This is called the baseline estradiol level. Twelve hours after the tablet was inserted, the women had estradiol levels that were 16 times higher than baseline levels.
Women who used the vaginal estradiol ring had estradiol blood levels that were 3 times higher than the estradiol blood levels of women who never used a vaginal estradiol preparation right before the next ring was to be inserted (baseline level). Eight weeks after the ring was inserted, the women had estradiol levels that were more than double the baseline levels.
These results suggest that using a vaginal hormone preparation to help ease atrophic vaginitis after menopause may not be a good idea for women who have been diagnosed with hormone-receptor-positive breast cancer. While these products can help improve the vaginal lining and lubrication, it's possible they may increase the risk of breast cancer recurrence, though an increase in recurrence risk hasn't been shown by this or other research.
If you're troubled by postmenopausal vaginal dryness, there are non-hormonal options that you might want to consider, including vaginal moisturizing products. Talk to your doctor about your symptoms and your options -- both hormonal and non-hormonal -- that can help you get relief.