News Releases

Does Soy Relieve Breast Pain? Volunteers Needed for Study

Can soy relieve breast pain? A growing number of women who suffer from mastalgia (breast pain) say it does.

To test the claim, public-health researchers at the Fred Hutchinson Cancer Research Center are launching a pilot study that will enroll 30 women to determine whether the soy/mastalgia connection is strong enough to merit a full-fledged investigation. It is the first study of its kind to look at the effect of soy on breast pain.

While the study is open to the public, participants also will be recruited from the Breast Care Program of Providence Medical Center and its affiliated network of primary care clinics. Hutchinson Center researchers and Providence physicians and support staff are donating their time and expertise for the study.

A clue to soy's potential influence may lie in isoflavones (eye-so-FLA-vones), a type of phytoestrogen, or plant-based estrogen, that biologically mimics the human hormone, says Johanna Lampe, Ph.D., R.D., who heads the six-month study.

"The structure of isoflavones is similar to that of human estrogen, and studies show that they have weak estrogenic effects," Lampe says. "Because breast pain often coincides with hormone cycles, it is biologically plausible that isoflavones may have an effect." Lampe, whose research focuses on understanding how plant-based diets lower cancer risk, is an assistant member at the Hutchinson Center's Division of Public Health Sciences and a research assistant professor of epidemiology at the University of Washington.

Although frequently regarded as only a nuisance, mastalgia is the leading breast-related complaint among women seen in primary- and breast-care clinics. The condition affects an estimated 40 percent to 70 percent of women. Half of these women experience breast pain that waxes and wanes during each menstrual cycle, while half endure persistent pain.

As many as 30 percent of women with mastalgia report that it significantly interferes with social, physical and sexual activities, Lampe says.

Women may be eligible to enroll in the Soy and Pain Relief Trial if they:

  • are 30 to 45 years old;
  • have breast pain;
  • are not on birth control pills or hormone therapy; and
  • have never had breast cancer.

Researchers will assign participants randomly to two groups. Half will incorporate two servings of soy powder without isoflavones into their usual food and drink for 100 days; the other half will consume equal amounts of isoflavone-containing soy powder.

During the trial, each woman will undergo four complete breast exams, four blood tests, and two ultrasound examinations of the uterus and breasts. Participants also will record daily body temperature and symptoms of breast pain, and fill out a diet questionnaire.

Using this data, researchers will assess changes in breast pain, breast lumps, menstrual cycle length and tissues affected by estrogen, including bone.

Interested women who meet the study criteria are encouraged to call project director Neilann Horner at the Hutchinson Center's Cancer Prevention Research Program, (206) 667-4421.

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CONTACT: Kristen Woodward
(206) 667-5095

Dec. 14, 1998


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