For women who have had breast cancer, HRT may not be the answer to controlling menopausal symptoms, says oncologist Herman Kattlove, MD, of the American Cancer Society (ACS). Although some studies have shown that breast cancer survivors who took HRT had no more breast cancer recurrences than those who did not take HRT, no randomized clinical trial has been performed, so doctors can’t be entirely sure HRT is safe for breast cancer survivors, Dr. Kattlove says.

Menopausal women who have had breast cancer have been increasingly turning to "natural" substances for relief from menopause-related health complaints. Potential natural remedies include the phytoestrogens (plant compounds that mimic some actions of estrogen) derived from soy products, which have been touted as beneficial for women suffering from hot flashes. A study published in a recent issue of the Journal of Clinical Oncology (Vol. 18, No. 5) looked into whether or not soy actually works to relieve hot flashes.

Researchers had previously observed lower breast cancer rates and fewer complaints related to menopause in Asian women, whose diet is typically rich in soy-based foods.

In this study, researchers led by Susan K. Quella, RN, of the North Central Cancer Treatment Group (NCCTG) at the Mayo Clinic in Rochester, Minn., developed a soy tablet equivalent to or greater than the amount of soy in the average Japanese woman’s diet and studied the effects of the tablets in reducing hot flashes in 155 breast cancer survivors. The women were given soy tablets every day for one month and a placebo (sugar pill) for another month. The participants kept a record of the number and intensity of hot flashes they experienced. At the trial’s end, the researchers concluded, "The soy product did not alleviate hot flashes in breast cancer survivors."

"This study is very significant in that it proved that although soy may be beneficial in helping prevent heart disease and osteoporosis, it is not beneficial in reducing or eliminating hot flashes," said Quella.

But the women in the trial took soy tablets instead of eating soy-based foods, and that could have had an impact on the results, Dr. Kattlove says. "Many studies of chemicals thought to be the active ingredient in natural foods have not shown expected benefits. There is no substitute for the whole food. We don’t know exactly what it is in fruits, vegetables and soybeans that exerts its therapeutic effect."

The researchers who conducted the study wrote, "It is possible that another soy-based preparation might alleviate hot flashes, but a more definitive claim of such requires demonstration by a definitive clinical trial."

Dr. Kattlove and Ms. Quella both recommend that breast cancer survivors suffering from hot flashes and other related problems speak to their doctors about finding an appropriate method to reduce their symptoms.

Ms. Quella said more studies are underway to find ways to combat symptoms related to menopause. "The NCCTG has been testing substances to combat that problem for years and will continue to do so until we find something that works well, with little side effects, and that all women can take," she says.