DES Daughters: New Study Shows Increased Breast Cancer Risk

PJ Hamel Health Guide
  • Were you born between 1938 and 1971? Then there’s a chance your mother was prescribed a certain hormone drug to prevent miscarriage. If she was, you’re at increased risk for a host of health problems – including breast cancer.

    It was a miracle drug. A way for a woman prone to miscarriages to carry her baby full-term. To give birth to a healthy baby.

    To become a mother.

    Which, back in the years when the drug was prescribed, was the dream of most women: motherhood.

    While the ‘60s produced the sexual revolution and women’s liberation, old ways died hard. Well into the ‘70s, many women, even if they went to college, had one goal in mind: to get married and become a mom. (Back then, the “stay-at-home” part was assumed.)

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    And if you were unable to successfully complete a pregnancy, there was help for you: diethylstilbestrol (DES) – the first synthetic form of estrogen, prescribed by doctors as early as 1938 to prevent miscarriage and other complications of pregnancy.

    Problem was, by the 1950s it had become evident that DES wasn’t doing its job; clinical studies proved it ineffective. Yet doctors, no doubt spurred by the drug’s popularity, continued to prescribe it; over the course of the more than 30 years when it was in use, it’s estimated between 5 million and 10 million pregnant women took DES.

    What finally removed DES from the market? In the late 1960s, young women in their 20s whose mothers had taken DES began showing up with rare vaginal cancers, cancers which had previously been seen only in much older patients: women in their 60s.

    Researchers eventually linked these rare vaginal cancers to DES exposure in the womb. And by 1971, the FDA had advised doctors to stop prescribing it.

    But its effects on the daughters of women who took the drug – a group researchers call DES Daughters – are continuing to be discovered, especially as these women grow older. In addition, there’s a possibility that DES exposure caused genetic changes that can become hereditary; so DES granddaughters are now involved in research, as well.

    A 20-year study, published last October in the New England Journal of Medicine, lists 12 known health conditions with direct links to DES exposure. Eight of these are fertility-related, ranging from ectopic pregnancy, to infertility, to miscarriage. Of the remaining four, two are cancers: clear cell adenocarcinoma, a rare vaginal cancer; and breast cancer.

    According to the study, breast cancer risk for DES Daughters over the age of 40 is nearly double that of the general population. This means that while all DES daughters are subject to the same “1 in 8 lifetime risk” other women worry about, an additional 1 in 50 will develop breast cancer as a result of their DES exposure.

    A lawsuit has recently been filed on behalf of 53 women around the country, who claim their breast cancer was caused by DES. The suit against 14 drug manufacturers, including Bristol-Myers Squibb and Eli Lilly, will reach a critical juncture Jan. 19, when U.S Magistrate Judge Marianne Bowler will rule on the drug companies’ motion to exclude testimony from the plaintiff’s experts.

  • The drug companies’ motion reads, in part, “There is not a single published study, a respected medical treatise or textbook, nor a pronouncement by one of the prominent societies dedicated to the discovery of cancer causes which claims a causal link between prenatal DES exposure and breast cancer has been proven.”

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    Apparently, the drug manufacturers discount both the study in the New England Journal of Medicine, and the study’s author: Dr. Robert Hoover, director of the Epidemiology and Biostatistics Program at the National Cancer Institute’s Division of Cancer Epidemiology and Genetics.

    It remains to be seen whether Judge Bowler agrees.

    Are you a DES Daughter? If you don’t know, ask. If you find out your mom took DES while pregnant with you, speak with your doctor about what this means for your health, going forward.

    All but the youngest of DES Daughters have started leaving their childbearing years – and the majority of DES-linked health issues – behind.

    But for the vast majority of Daughters – those over age 40 – one DES-linked risk still looms large: breast cancer.

    Be aware.

Published On: January 11, 2012