Q: My doctor says hormone replacement therapy could help relieve my horrendous hot flashes, but I’m afraid of developing breast cancer. Is it safe?

A: Breast cancer, the most common cancer in women, develops in one out of every nine women and is the second leading cause of cancer death, after lung cancer. There are several risk factors for breast cancer, and hormone replacement therapy (HRT) might be one of them.

About 80 percent of breast cancers are not hereditary. Those cases typically occur in women who have not yet gone through menopause. Established risk factors for breast cancer include early age at first period, later age at menopause, and first child born after age 30.

HRT is believed to slightly increase the risk of breast cancer, depending on the type of hormones prescribed. There are two main types of HRT: estrogen plus progesterone, which is used for women who have a uterus, and estrogen alone, which is used for women who no longer have a uterus. Progesterone protects women from uterine cancer.

The Women’s Health Initiative evaluated HRT and its impact on women’s health. It found that 38 out of 1,000 women who took estrogen plus progesterone developed breast cancer, compared with 30 out of 1,000 in the placebo group.

Women taking estrogen only had no increased risk of developing breast cancer. Estrogen alone, therefore, does not appear to increase the risk for breast cancer in postmenopausal women. Progestin appears to be the culprit.

Progestin closely, but not exactly, resembles the hormone progesterone, which is naturally produced by the ovaries. Progestins are the most common form of progesterone used in HRT in the U.S. In the Women’s Health Initiative study, progestins were paired with estrogen to reduce the risk of uterine cancer.

Micronized progesterone, which exactly replicates the structure of human progesterone, is the most common progesterone used in HRT in France. In a 2008 study in France, the use of HRT with micronized progesterone did not appear to increase the risk for breast cancer.

HRT is not your only option for relief of menopausal symptoms. The FDA has approved a non-hormonal medication that increases brain serotonin levels and decreases hot flashes. It is not as effective as estrogen, but it is a good alternative.

Breast cancer is only one factor to consider when deciding whether to stop or start using HRT. Talk to a health care provider who has experience treating postmenopausal symptoms about your options.

Joanne Price Williamson, M.D., is an obstetrician-gynecologist in practice at Memorial Health University Physicians-Provident OB/GYN Associates at Legacy Center in Okatie.