The University of Chicago

Registry for Research on Hormonal Transplacental Carcinogenesis

Frequently Asked Questions

What is CCA?

Clear cell adenocarcinoma (CCA) of the vagina and/or cervix is a very rare type of cancer, so named because of the way the cells look under a microscope. The Registry specifically studies CCA of the vagina and cervix in young women born after 1948. The age range (age at diagnosis) of DES-exposed females with this type of cancer who have been reported to the Registry is from 7 to 62 years of age, although most of the known cases of CCA of the vagina and cervix have occurred in women in the United States in their late teens and early twenties. Previously (in the pre-DES era) these vaginal cancers were found only rarely and then primarily in women over 50. The upper age limit for developing CCA is unknown.

Should I register?

The Registry has accessioned over 700 cases of clear cell adenocarcinoma (CCA), 2/3 of which are associated with prenatal diethylstilbestrol (DES) exposure. The initial age-incidence curve showed a peak between ages 15-25 years among the DES-exposed. There is a suggestion of a possible increase in frequency among DES-exposed beginning to appear in those over 40 years of age. Cases of primary adenocarcinoma of the endometrium in patients under age 40 have been reported to the Registry, as well as isolated cases of primary mucinous adenocarcinoma of the vagina in the DES-exposed. These sporadic occurrences are currently under investigation. 

Therefore, we accession the following cases:

    • Any cases of CCA of the vagina and/or cervix in a patient born since 1948 regardless of DES exposure
    • Mucinous carcinoma of the vagina in the DES-exposed
    • Fallopian tube carcinoma in a DES-exposed woman

These categories provide areas of investigation to determine:

    • If there is a second rise in the age-incidence curve beyond the age of 40 years in the DES-exposed
    • If mucinous adenocarcinoma of the vagina begins to occur in excess in this cohort
    • If carcinoma of the fallopian tube begins to occur (currently, no cases have been reported)

How do I register?

Contact our office

Our staff will be able to guide you through the process (described briefly below):

  1. Gathering relevant information from you
  2. Signing an informed consent
  3. Filling out a registration form
  4. Contacting your physician to verify your diagnosis

What is DES and when was it used?

DES is a synthetic form of estrogen, which is a female hormone. DES is also an example of an estrogen disruptor, i.e. it is a chemical that interferes with the body’s hormone system. It was first synthesized in 1938 and was the first orally active estrogen. It became very popular for use during pregnancy to prevent miscarriage. It was estrogen in pill-form that could be taken daily in small amounts. It was believed that the extra estrogen taken during pregnancy would help a pregnant woman have a healthy baby. DES was used from approximately 1941 until it was banned for use in pregnancy in 1971. The exact number of women who took DES during pregnancy is unknown, but it has been estimated that approximately two to four million women were treated during pregnancy with DES or other nonsteroidal synthetic estrogens, such as dienestrol or hexestrol.

Why study DES?

The most important reason to study DES is to provide DES-exposed people and medical professionals with information about the long-term health effects of DES exposure.  DES is often used as a way of studying how chemicals that act like or interfere with hormones in the body affect health. Although numerous cancer-causing agents are known to pass from the placenta to the fetus in animals, DES is unique because it is the only agent known to do the same in humans. 
Finally, the study of DES may aid in understanding the effects of hormones, in general, during the development of the fetus.