Women whose mothers took the fertility drug DES may face a far greater risk of developing breast cancer.
Although doctors were aware of the greater risks among the mothers themselves, they are now noticing cases among the daughters as well.
Specialists from the British Columbia Cancer Agency have reported two cases both daughters of DES patients, aged 28 and 34 who have breast cancer.
DES (diethylstilboestrol) was used extensively to treat possible miscarriage and infertility up until 1971 in the US, and until 1978 in Europe, when the drug was removed from the market. DES is one of the few external factors accepted as increasing the risk of breast cancer among women; the other two are alcohol and ionizing radiation. The risk among DES mothers increases by 35 per cent.
It has been recognized that DES daughters are more likely to develop cervical cancer, and suffer premature births and miscarriages, but it was thought the breast cancer risks were not passed on.
"We may now begin to see the full extent of its effects as DES daughters grow older," say the doctors in a letter to The Lancet.
!AThe Lancet, 1996; 348: 331.