Few studies have been conducted on health risks for men exposed
to DES in utero (DES Sons). These have generally yielded mixed results.
An increased risk of epididymal cysts has been documented in DES
Sons in several studies (196,201,209,225,236). These demonstrated
that 21% of DES Sons had epididymal cysts, compared to 5% of unexposed
men. Risks of other genital abnormalities, including testicular
hypoplasia, cryptorchidism, and microphallus have been reported
to be more common among DES Sons in some studies, but not others
Lack of Increased Risk of Infertility
Data from a prospective, blinded, placebo-controlled study of prenatal
DES exposure confirmed no impairment in fertility in men exposed
to DES in utero (DES Sons) (2,236).
issues limiting firm conclusions about effects of DES on men exposed
in utero (DES Sons) have been small sample size, lack of randomization,
and the relative youth of the study cohort. From a clinical standpoint,
the most important issue is that the median age of men in reported
DES cohort studies is less than 50. Thus it is possible that health
effects may be found that affect elderly DES Sons that are not currently
Significant bias is introduced into non-randomized studies because
men with genital abnormalities are more likely to investigate whether
they were exposed to DES, and thus be identified as DES Sons. Data
from a cohort of offspring of women randomized to DES or placebo
during pregnancy exist, but sample sizes are relatively small.
risk of epididymal cysts has been documented consistently in DES
Sons. Risks of other genital abnormalities (testicular hypoplasia,
cryptorchidism, microphallus) have been associated with DES exposure
in some studies, but not others (206,217,233,236). It is unlikely
that this issue will ever be definitively resolved.
Some case control
studies have suggested an increased risk of testicular cancer in
DES Sons, others have not. A prospective randomized study found
a trend to increased levels of testicular cancer compared to a control
group that was not statistically significant (231). Based on animal
studies, it is possible that significant cancer risks will be identified
as men age.
Rete Testis and Prostatic Utricular Cancer
Studies of mice exposed prenatally to DES have demonstrated an
increased incidence of tumors of the rete testes and metaplastic,
dysplastic, and neoplastic changes in the Prostatic utricle (219,220,221,223,224,225).
These organs develop from the same embryonic tissue (the Müllerian
duct) as the vagina, the site of known increased cancer risk in
DES Daughters. Cancers develop in older DES-exposed mice, correlating
to old age in humans. Although such tumors have not been demonstrated
to occur more frequently in DES Sons, the possibility remains that
they will be detected as the cohort ages.
For a complete list of the numbered citations
on this page see DES References.
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