Sexuality and Reproductive Issues (PDQ®): Supportive care - Health Professional Information [NCI] - Treatment of Sexual Problems in People With Cancer
Only two published studies have evaluated transdermal testosterone for libido in postmenopausal women without estrogen supplementation. One of these studies was in cancer survivors, and the other was in postmenopausal women who were diagnosed with hypoactive sexual desire disorder.[Level of evidence: I] The clinical trial in cancer survivors showed that in 150 female cancer survivors randomly assigned to receive either 10 mg of transdermal testosterone daily or placebo for 4 weeks, there was no statistically significant difference in improvement in sexual desire as measured by a validated sexual function scale, the Changes in Sexual Functioning Questionnaire, despite the fact that androgen levels improved significantly in the women receiving the testosterone but remained unchanged in the women receiving placebo. The other clinical trial randomly assigned 814 postmenopausal women to receive either 150 µg or 300 µg of transdermal testosterone versus placebo for a year (without estrogen), with an efficacy endpoint of 24 weeks looking at satisfying sexual episodes captured in activity logs. Authors reported a significant improvement of about one additional satisfying sexual episode over a 4-week period in the 300-µg group compared to placebo, but not in the 150-µg group. Upon further analysis, it was found that women who had experienced surgical menopause, having had their ovaries removed, did not benefit from this intervention. This raises the questions of whether ovarian status in women who have been treated for cancer with chemotherapy is more like surgical or natural menopause, and whether the chemotherapy-induced menopausal ovary functions with an active stroma or has no activity after chemotherapy, akin to surgical removal. Research in this area is needed to better understand the entire hormonal milieu of women after cancer treatment and how all of the hormone changes work together to impact symptoms. Therefore, it is not clear that testosterone alone, in the absence of estrogen, can positively impact libido.
For women who have breast cancer, the safety of giving androgens is unknown. Serum androgens can be aromatized to estrogen. Data from epidemiologic studies can lead one to believe there may be an increased risk of breast cancer with higher concentrations of endogenous androgens.[68,69] However, endogenous androgens present over a life span do not equal exogenous androgen supplementation for a woman with low androgen concentrations. One small study evaluating the effects of testosterone supplementation on breast tissue found that the addition of testosterone to estrogen and progesterone inhibited the breast proliferation exhibited in the group that received estrogen, progesterone, and placebo.[Level of evidence: I] Furthermore, one case-controlled study in more than 8,000 women found that the use of exogenous testosterone for 4 years did not result in an increased incidence of breast cancer, despite the fact that 83% of testosterone users were also using estrogen replacement compared to only 15% of the age-matched controls.[Level of evidence: III] Therefore, many unanswered questions remain about sufficient androgen levels for adequate sexual function as well as short- and long-term safety. To date, there are no compelling data to support the use of testosterone alone to improve libido in women who are estrogen deficient.