DES Daughters over age 40 are nearly two times as likely as unexposed women to develop breast cancer. For DES Daughters older than age 50 the relative risk is estimated to be even higher. The breast cancer risk for DES Mothers is approximately 30% higher (considered moderately higher) than for women not given DES during pregnancy.
As a result, DES Action USA encourages DES Mothers and DES Daughters to remind their health care providers of their increased breast cancer risk and discuss an appropriate screening regimen. For most it means annual mammograms coupled with annual clinical breast exams. Also, all women should pay attention to their breasts and alert their doctors if any changes are noticed.
Of note is that no specific tumor type or gene mutation has been associated with DES Daughter breast cancer. Rather, it’s suspected by researchers that prenatal DES exposure may increase the growth of any cells that develop into breast cancer. It is this potential for a more rapid growth rate that results in the increased risk for, and incidence of, breast cancer at an earlier age for DES Daughters.
The additional breast cancer risk for DES Daughters should be considered in decisions regarding hormone replacement therapy. When absolutely necessary, only the lowest dose of HRT for the shortest length of time should be considered. This current recommendation applies to all women, but especially DES Daughters and DES Mothers.
An interesting question being examined by researchers with the National Cancer Institute DES Follow-up Study is whether bra cup sizes may help explain the DES Daughter link to breast cancer. The thinking is that prenatal DES exposure may increase mammary gland cell formation – hence larger bra cups. An initial study found support for the hypothesis that in utero DES exposure may result in greater mammary mass, which is believed to raise the risk for breast cancer.
Clear Cell Adenocarcinoma (CCA) of the Vagina and Cervix
The risk is small, estimated at about 1 in 1,000 for this rare cancer. It was once thought DES Daughters over age 30 were no longer at risk, but we now know CCA is a lifelong concern. Cases have been reported in Daughters older than age 50, when CCA also may occur in the unexposed population. Researchers are now watching for a possible spike in cases in post-menopausal DES Daughters. A population-based analysis by CDC researchers suggests an elevated CCA risk for DES Daughters as they age. Studies are underway, but at this point there does not appear to be an upper age limit for this cancer in DES Daughters.
- Cervical Cancer Vaccine
The cervical cancer vaccine that is now available does NOT protect against the type of cancer linked to DES exposure, which is clear cell adenocarcinoma (CCA) of the cervix and vagina. What the vaccine does is provide protection against the more common types of cervical cancer and genital warts that are caused by the Human Papillomavirus (HPV).
Testicular Cancer (Possible)
No DES-specific testicular cancer has been found; however, research shows that congenital abnormalities such as undescended testicles predispose men to testicular cancer. Therefore, DES Sons, with a higher rate for such urogenital anomalies, might be considered as a high-risk group. All men should practice testicular self-exam and do so regularly.
Prostate Cancer (Possible)
DES Sons are reaching, or are in the age when prostate cancer may occur, but there have not been reports of an increased incidence of prostate cancer in DES Sons. That said, animal studies point to the possibility of an heightened risk for DES-exposed men, leading some researchers to speculate that DES Sons could be at higher risk and should pay attention to the possibility.