Lesbians & Breast Cancer

In the early 1990s, researcher Suzanne Haynes, then an epidemiologist at the National Cancer Institute, investigated whether known risk factors for breast cancer occurred more frequently in the lesbian population. Haynes found that risk factors such as not having children, being overweight, smoking and excessive drinking were significantly more common among lesbians than women in general. Results from this study suggested that lesbians’ risk for breast cancer could be two to three times greater than for straight women.

Fortunately, other study results released in 2002 indicate that our breast cancer risk is not quite as dire as previously supposed. Suzanne Dibble, professor of nursing at the UCSF Institute of Health and Aging and co-director of the UCSF Center for Lesbian Health Research, decided to measure actual incidence of breast cancer among lesbians. With a grant from the California Breast Cancer Research Fund, Dibble and her colleagues recruited lesbians over 40 to participate in the study. Participants were asked to recruit a sister who was straight and a heterosexual friend to provide a comparison group. Nearly 1,000 lesbians were recruited, as well as 324 lesbian-sister pairs.

As expected, the lesbians were less likely to have had children and were more overweight than their heterosexual sisters. However, the study did not find a significant difference in alcohol use, and the lesbians actually smoked less than their sisters.

Breast cancer rates were slightly higher for lesbians, but nowhere near the earlier estimates. Dibble calculated that the lesbians had an 11.1 percent risk of developing breast cancer over their lifetime, compared to a 10.6 percent risk for their sisters. This means that 110,000 out of one million lesbians would develop breast cancer, compared to 106,000 of their heterosexual sisters.

Suzanne Haynes, who is now president of the Lesbian Health Fund, said the problem with inferring incidence rates from Dibble’s study is that participants were all California lesbians, who may be healthier than those in other states.
In addition, the study did not focus on women over 50, who are most likely to develop breast cancer. The true facts about lesbians and breast cancer may not be known for years, since the disease typically strikes when women are much older than those in the UCSF study, according to Susan Cochran, a professor of epidemiology at UCLA.

Risk Factors
While it no longer appears that breast cancer is an epidemic among lesbians, it is still important to acknowledge that we have some known risk factors for developing breast cancer in greater incidence than heterosexual women. Results from a 2001 study conducted by Cochran found that in comparison with estimates for the overall U.S. female population, lesbians and bisexual women exhibit greater prevalence rates of obesity, alcohol use, and tobacco use and lower rates of childbirth and birth control pill use.

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