DES Cancer Risk After in Utero Exposure Persists

If you want to know about this in depth, read Hormonal Disruption by Lindsey Berstrom... it's a bit depressing, but an important issue.

NEW YORK (Reuters Health) Aug 10 - The increased risk of vaginal and cervical cancer in young women prenatally exposed to diethylstilbestrol (DES) remains elevated through the reproductive years, according to findings published in the July 15th issue of the International Journal of Cancer. However, the risk only applies to clear cell adenocarcinomas and breast cancer among women 40 or older.

"In 1971, a strong association was reported between DES and clear cell adenocarcinomas of the vagina and cervix in young women," Dr. Rebecca Troisi, of Dartmouth Medical School, Hanover, New Hampshire, and colleagues write.

"Animal studies suggest the teratogenic and carcinogenic effects of prenatally administered DES may be due to changes in the expression of genes involved in the development of the reproductive tract and raise concerns of elevated risk of other female reproductive tract cancers besides clear cell adenocarcinomas, they add.

To examine if the overall cancer risk is elevated after prenatal DES exposure, they used data from the DES Combined Cohort Follow-up Study to assess total and site-specific cancer risk comparing women exposed to DES versus unexposed women.

Exposed and unexposed women were followed for a total of 97,831 and 34,810 person-years, respectively. During that time, there were a total of 143 cancer cases in the exposed group and 49 cancer cases in the unexposed group.

They found that age-adjusted incidence rate ratio for exposed versus unexposed women for all cancers was 1.32, a non-significant difference.

No association was observed between DES and excess risks of endometrial or ovarian cancer.

As expected, in DES-exposed women, the risk of vaginal and cervical clear cell adenocarcinomas was higher through age 40, and the age-adjusted incidence rate ratio for breast cancer was 1.83, but only for women 40 years of age or older.

Int J Cancer 2007;121:356-360.