Cancer risk in women prenatally exposed to diethylstilbestrol.
Prenatal diethylstilbestrol [DES] exposure is associated with higher risks of clear cell adenocarcinoma [CCA], and breast cancer in older women. Whether the overall risk of being diagnosed with any cancer is also elevated is unclear. A total of 143 exposed women and 49 unexposed women in the DES Combined Cohort Follow-up Study were diagnosed with cancer as of 2001. Compared with breast cancer rates in the general US population, there was no overall higher risk among DES exposed women. Comparing exposed with unexposed women within the study, there was about a 30% increase in cancer risk but this finding could be due to chance. As reported in a previous article (Palmer 2006), breast cancer risk was elevated but only among women over 40 years of age. Exposed women had a risk of CCA that was nearly 40% higher than the general population, however; the incidence of CCA decreased substantially after age 25 compared with women 20 to 24 years old. Excluding CCA and breast cancer, the higher risk of cancer among the DES exposed women was about 20%, a result that could be due to chance. DES was not associated with higher risks of either endometrial or ovarian cancer. These data suggest that the DES associated increase in CCA rates remains elevated through the reproductive years. There was no consistent evidence of a higher risk for cancers other than CCA, and breast in older women. Given that the population is still young, continued follow-up is necessary to assess the overall cancer risk associated with prenatal DES exposure.