Increasing the testosterone levels of female cancer survivors using testosterone cream did not improve their libido more than a placebo, according to a randomized controlled clinical trial in the May 2 Journal of the National Cancer Institute.

Female cancer patients often experience decreased sexual desire, and previous studies have shown an association between testosterone therapy, also called androgen therapy, and increased libido in women with adequate estrogen levels.

Debra Barton, Ph.D., of Mayo Clinic in Rochester, Minn., and colleagues conducted a randomized phase III clinical trial to determine whether testosterone treatment improved libido in 150 postmenopausal cancer survivors. The women were randomly assigned to receive a testosterone cream or a placebo daily for four weeks, then they were switched to the other treatment group for an additional four weeks. The researchers measured the women’s sexual desire with a questionnaire before treatment, then again at four and eight weeks.

There was no statistically significant difference in libido between the testosterone and placebo groups during the first or second 4-week treatment period. Both groups showed increased libido compared with levels before treatment, which suggests a placebo effect. The researchers propose that their negative results could be explained by low levels of estrogen among the study participants.

"If providing supplemental estrogen to women who are postmenopausal is required to obtain a benefit from androgen therapy, then it does not appear that androgen supplementation would be a viable option for women who must avoid [estrogen] replacement," the authors write.

In an accompanying editorial, Patricia Ganz, M.D., and Gail Greendale, M.D., of the Jonsson Comprehensive Cancer Center at the School of Public Health and the David Geffen School of Medicine at the University of California, Los Angeles, discuss the complexities of sexual desire and response in women. They suggest that, given the high rates of sexual dysfunction among women in general, focusing only on hormones might be oversimplifying the issue. "Although ovarian hormones play an important role in the maintenance of sexual health in women, a large body of evolving information about sexual functioning (and dysfunction) suggests that these hormones may be necessary but not sufficient to overcome disorders of desire and arousal in women," the authors write.

Article: Barton DL, Wender DB, Sloan JA, Dalton RJ, Balcueva EP, et al. Randomized Controlled Trial to Evaluate Transdermal Testosterone in Female Cancer Survivors With Decreased Libido: North Central Cancer Treatment Group Protocol N02C3. J Natl Cancer Inst 2007; 99: 672-679

Editorial: Ganz PA, Greendale GA. Female Sexual Desire—Beyond Testosterone. J Natl Cancer Inst 2007; 99: 659-661