Diethylstilbestrol or DES associated with a higher risk of breast cancer in daughters.

The report of a study from the United States showed that women who were exposed to DES when their mother took the drug while pregnant have a risk of developing breast cancer that may be 40% higher than the risk for women who were not exposed to the drug. Breast cancer develops in these ‘DES daughters’ after the age of 40.

Professor John Boyages, Executive Director of the Westmead BCI said that “DES in the past had been associated with a number of conditions including a high incidence of a type of vaginal cancer, increased risk of cervical cancer and there have been previous reports linking it to breast cancer”. It is not known accurately how many people in Australian are affected by DES, but it is thought that there may be in excess of 15,000 DES daughters.

Professor Boyages cautioned, however, not to panic about this research as a 40 percent increase is still very small. He said that the risk of a 50-year-old woman developing breast cancer by the time she is 80 is one in 16 and this is increased to 1.4 in 16 if they happen to have a mother who was taking DES.

The problem is that many women at that time were taking various medications such as a progesterone or Beta HCG or DES and often the daughters don’t really know what medicine they took.

Professor Boyages also said that “there is no specific test that helps us determine whether someone’s mother had taken DES unless their mother does have some evidence to suggest this”.

Professor Boyages alerted people to the Centers for Disease Control and Prevention (CDC) website which gives a self-assessment guide as to whether people may have been taking DES. Potential clues are:

· The mother was pregnant between 1938 and 1971

· The daughter was born in the same years

· The mother definitely had DES

· The mother had previous miscarriages and had a “tablet” to prevent the miscarriage

· The daughter had an abnormal shape of some of her reproductive organs such as a “T-shaped uterus”.

Professor Boyages advised that women who are concerned see their doctor. Women who think they may be at risk of DES- related problems should make sure they have regular breast screening (a mammogram every year) and to perform breast self-examination. These women should also have a special DES pelvic examination which is a more detailed examination than a regular pap smear.

From the website of the Westmead Breast Cancer Institute www.bci.org.au. September 2006.

References:

Palmer JR, Wise LA, Hatch EE et al. Prenatal diethylstilbestrol exposure and risk of breast cancer. Cancer Epidemiol Biomarkers Prev 2006;15(8):1509-1514.

www.cdc.gov/DES/consumers/guide/audience2/index.html