Dyspareunia, or painful sexual intercourse, is a common side effect of breast cancer treatment due to low estrogen

Scientists at Oregon Health & Science University report that breast cancer survivors who experience pain during sexual intercourse, a common side effect of breast cancer treatment, may achieve comfort when liquid lidocaine is applied strategically to prevent pain. Their research was published online in the Journal of Clinical Oncology.

"The physical and psychological consequences for the more than 2.8 million breast cancer survivors in the U.S. are very real and often misunderstood, or not treated," said Martha F. Goetsch, M.D., M.P.H., adjunct assistant professor in the OHSU Department of Obstetrics and Gynecology, the study's lead author. "This noninvasive treatment will offer distinct help in alleviating the physical -- and quite frankly the emotional -- pain associated with sexual intercourse, making sexual function more enjoyable and fulfilling for them and their partner."

It is estimated that anywhere from 70 to 100 percent of breast cancer survivors, including those treated at OHSU Knight Cancer Institute, experience some sort of sexual dysfunction, including dyspareunia, which is the clinical term for pain during sexual intercourse. Breast cancer survivors are especially vulnerable to the condition because their treatment is focused on eradicating estrogen. This increases the severity of the typical menopausal symptom of pain with sex. A high proportion of women in menopause who have not had breast cancer also suffer from what is now termed vulvovaginal syndrome of menopause where estrogens decline.

The first paper published by Dr. Goetsch and colleagues about this study in the journal Obstetrics & Gynecology in 2014 discussed where breast cancer survivors experienced the most severe tenderness, which was in the vulvar vestibule, the part of the vulva inside the labia minora at the entryway to the vagina.

With this in mind, the researchers asked 46 estrogen-deficient breast cancer survivors with severe dyspareunia to apply one of two treatments they could not identify during the blinded phase. They got either saline or 4 percent liquid lidocaine and applied their liquid to the vulvar vestibule for three minutes before sexual intercourse. They also received a silicone lubricant.

Whereas initially the group had an average pain score of 8 on a scale of 1-10, results showed that those who used lidocaine and a silicone-based lubricant had a much lower pain level, 1.0 on scale of 1-10, compared with those who used saline and silicone lubricant, 5.3 on a scale of 1- 10. After knowingly using lidocaine for two more months, 90 percent of study participants reported comfortable penetration, when initially half had found such intimacy too painful to try. Sexual distress also decreased and sexual function improved. Importantly, no partners reported numbness.

"As gynecologists, we should be doing everything we can to help breast cancer survivors improve their quality of life through medical treatments that can alleviate pain and suffering," said Aaron B. Caughey, M.D., Ph.D., professor and chair of the OHSU Department of Obstetrics and Gynecology, and associate dean for Women's Health Research and Policy in the OHSU School of Medicine. "We need more research on the consequences of breast cancer on women's health because there simply isn't a lot of research focusing on this issue."

Dr. Goetsch says that breast cancer survivors and post-menopausal women who experience pain during intercourse should talk to their health care providers about using the combination of liquid lidocaine and silicone-based lubricant to prevent pain. Liquid lidocaine is FDA approved for mucosal use and is available through prescription only.