The development of drug therapies to help women with breast cancer avoid another bout with the disease is good news. However, tamoxifen and the aromatase inhibitor class of drugs — which cut the risk of breast-cancer recurrence by 40–50 percent — are rife with side effects. And now a new study shows that one of those side effects can be a diminished sex life.
It may seem like a trivial concern compared to surviving a life-threatening illness, which may make some women reluctant to mention it. But dissatisfaction with one’s sexual relationships is important and should be discussed with a doctor, says the lead author of the study, Juliane Baumgart, M.D., of Örebro University Hospital in Sweden.
“I think that we clinicians often focus on the benefits of a given treatment,” Baumgart says. Most doctors talk to their patients about the riskiest side effects from taking a given medication. “Side effects affecting quality-of-life concerns like sexual problems are named less often,” she notes.
Tamoxifen and aromatase inhibitors are at the core of a cancer-treatment strategy called adjuvant endocrine therapy — or simply hormonal therapy. The drugs are prescribed to women who have been treated for estrogen-receptor-positive breast cancer, which means the tumors use estrogen to grow. About 80 percent of breast cancers in postmenopausal women are of this type.
Hormonal therapy begins after a woman completes her initial treatment (surgery, chemotherapy or radiation). Tamoxifen is a selective estrogen receptor modulator (SERM), which means that it blocks the body’s own estrogen’s uptake by cells in the breast, stopping any remaining cancer cells from using the hormone to roar back. Aromatase inhibitors work a bit differently by stopping an enzyme called aromatase from changing other hormones into estrogen. Aromatase inhibitors are prescribed only to women who have completed menopause.
Women typically are told to take hormonal therapies for five years. But both types of drugs can interfere with sexual functioning, according to Baumgart. She and her colleagues surveyed 82 women who had breast cancer and had been taking tamoxifen or aromatase inhibitors. Aromatase inhibitors include the drugs exemestane (Aromasin), letrozole (Femara) and anastrozole (Arimidex).
The women were all between the ages 55 and 70 and had been diagnosed with breast cancer two to six years earlier.
The study, published in the journal Menopause, showed aromatase inhibitors are more problematic. Among the women who were sexually active, 74 percent taking aromatase inhibitors said they always or almost always had inadequate lubrication during sex compared to around 40 percent of the same-aged women who had not had cancer or who were treated with tamoxifen.
Painful sex was reported by 57 percent of the women taking aromatase inhibitors compared to 31 percent taking tamoxifen and 21 percent in the comparison group. There was no difference in the groups regarding the ability to reach orgasm. However, women taking aromatase inhibitors more likely to say they were generally dissatisfied with their sex lives.
Meanwhile, research is making it clear just how important aromatase inhibitors are to women with estrogen-receptor-positive breast cancer. In 2010, the American Society of Clinical Oncology issued updated guidelines on adjuvant hormonal therapy for postmenopausal women recommending the use of an aromatase inhibitor at some point, whether as the front-line therapy or following the use of tamoxifen. The experts concluded that adding an aromatase inhibitor to the treatment plan improves survival compared with just taking tamoxifen alone.
Helping women with sexual side effects and other problems linked to these medications is critical, Baumgart notes. While tamoxifen increases the risk of blood clots, aromatase inhibitors can speed up bone loss and the onset of osteoporosis. And both types of drugs cause muscle and joint pain and headaches.
A 2010 study of more than 8,700 women illustrated the extent of women’s troubles with hormonal therapies. Researchers at the University of California, Los Angeles, found that about half of all patients stopped taking their medications ahead of schedule.
Having an unsatisfactory sex life is a big reminder of the toll cancer has taken on one’s life. Women taking hormonal therapy after breast cancer should tell their doctors about any problems with sexual function. Non-estrogen-containing lubricants, such as water or silicone-based products, may help. Topical vaginal estrogen lubricants aren’t recommended for women with this type of cancer, Baumgart notes.
“Right now, we have the problem that there is a lack of studies on possible treatment options for patients with [insufficient lubrication] or sexual dysfunction,” she says. “Systemic estrogenic treatment (pills/patches/creams) is advised against because of increased risk for cancer recurrence.”
Since tamoxifen and aromatase inhibitors are so vital to preventing breast-cancer recurrence, it’s time for researchers to look harder at how all types of side effects can be managed so that women can stay on the medications — without these side effects — for as long as necessary, she says.
For more news about breast-cancer prevention, diagnosis and treatment, check out “4 Breast-Cancer Breakthroughs” in the latest issue.
Are you less likely to discuss some medication side effects with your doctor than others?
Image credit: Dung Hoang