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Women whose mothers took synthetic estrogen known as DES are at increased risk of developing breast cancer later in life. DES was used during the 1950s and 60s to prevent miscarriage.
NPR's Patricia Neighmond reports on the new research.
PATRICIA NEIGHMOND reporting:
DES children have been the subject of study ever since the ‘70s, when it was discovered that the daughters suffered a dramatic increase in a rare form of vaginal cancer. But the findings of this study are worrisome because breast cancer is more common.
Julie Palmer is an epidemiologist at the Boston University School of Public Health. She headed the research, which analyzed medical histories of over 4,800 women who were exposed to DES in utero, comparing them to over 2,000 women who were not exposed.
Ms. JULIE PALMER (Boston University School of Public Health): And we compared the incidents of breast cancer in the exposed to the incidents in the unexposed and found that the DES-exposed women had approximately 1.9 times the risk of breast cancer as the unexposed women.
NEIGHMOND: In addition to family history, there are a number of other factors that can up a woman's risk for breast cancer, including age, weight gain, alcohol use and high-fat diets. Overall, the findings are unwelcome news, says Palmer, for a group of women who've already suffered other DES-related problems.
Ms. PALMER: That's similar to having a first-degree relative, a mother or a sister, who has breast cancer. So it does put the woman into a higher-risk group.
NEIGHMOND: Researchers don't know why women who were exposed to DES in utero are at an increased risk for breast cancer, although it is known that other forms of estrogen do increase the risk. Dr. Hugh Taylor is an OB/GYN at Yale University School of Medicine. He says early evidence in animals indicates that some of the same defects in the uterus that result from DES exposure also affect breast tissue. He says the findings of the Palmer study should heighten awareness among women who were exposed to DES.
Dr. HUGH TAYLOR (Yale University School of Medicine): The best thing that someone can do now is be very vigilant about screening. With mammograms, we have the ability to detect breast cancers early, and I suggest that someone with DES exposure make sure they get their yearly mammogram from age 40 on. Be sure they're vigilant with their breast self-exams.
NEIGHMOND: Researcher Julie Palmer says DES daughters should also avoid exposure to other estrogens, including hormones prescribed to relieve menopausal symptoms. The study is published in the journal Cancer Epidemiology Biomarkers & Prevention.
Patricia Neighmond, NPR News. Transcript provided by NPR, Copyright NPR.