DES Sons and Cancer
"Prove it? I can't."

by Marie Cocking

Sons' stories

In 1976, Michael Du Bow was a 27-year-old geneticist working on a post-doctoral grant in a lab outside New York city when his mother told him she thought she had been given DES during her pregnancy.

Du Bow felt fine. But because DES had been linked to cancers in the daughters of DES mothers, he thought he'd better play it safe and get a complete check-up. His doctor found prostate cancer, an old man's disease.

Du Bow was lucky. His mother told him as soon as she suspected she had been prescribed DES and he took early action. He beat his cancer.

"Did DES cause my cancer? Prove it? I can't,'' says Dr. Du Bow, now a father of two and a professor at McGill University in Montreal. "But that's me being the rigourous scientist. I can't prove DES did it. You can even argue that there is no way to ever prove DES causes cancer [in men]."

"Why do I believe it? Because it fits the data. As my urologist says, I'm a urogenital disaster area."

Bryce Osborne wasn't so lucky. In March 1992, he noticed one of his testicles was tender. Four months and several specialists later, he lost his testicle to cancer. He was 32.

Osborne had no idea why he was struck with such a horrible disease until his sister sent him a magazine article about DES. He asked his mother and she remembered being given pills early in her pregnancy.

"Then, one day," says Osborne, now cancer-free, "she said the doctor called her up and said, 'Those pills I told you to take, stop taking them."' No explanations. When her son was born healthy, she forgot about it.

Did DES cause Osbome's cancer, too? Like Dr. Du Bow, he can't prove it. His mother's medical records have long since been destroyed. His mother remembers the pills were called something like "Estrobene," one of the brand names under which DES was sold. But even if both men could get their mothers' records, there is yet little research conclusively linking DES exposure to prostate and testicular cancers in sons.

Research: no link yet

Some researchers believe prenatal exposure to estrogens, like DES, is a risk factor in testicular and prostate cancers. Animal studies have demonstrated that prenatal exposure to DES can cause testicular and prostatic tumours.

A 1983 study looking at risk factors for testicular cancer concluded that men who were exposed to excess estrogens in the womb, as might happen when his mother was given DES during pregnancy, were eight times more likely to develop testicular cancer. The researchers found that men born with undescended testicles, not uncommon among DES sons, were nine times more likely to develop testicular cancer. And, in 1985, an informal survey by DES Action U.S.A found that 14 out of 94 self-reporting DES sons had "prostatic problems" - which is well above the less than one percent of prostate problems reported by men in the same age group.

But, according to Dr. Allen Wilcox, based at the National Institute of Environmental Health Sciences in the United States and one of a few experts on DES and health effects in sons, there have been no conclusive studies linking DES to cancers in men. So far, there have only been isolated case reports of urogenital cancers.

Dr. Wilcox and colleagues recently surveyed 500 DES sons and 400 non-exposed controls born in the Chicago area. The mothers of these DES sons were the original subjects of the 1952 study that eventually proved DES was not effective in preventing miscarriage. "It is fair to say," says Dr. Wilcox, although they are still analyzing their data, "that we do not see an excess of cancer among these DES sons." Their study has found more fertility problems in DES sons.

But, Dr. Wilcox cautions, many of these men are still relatively young. And there has been as yet no large-scale double-blind study of DES sons - the most rigourous of all scientific studies looking for all health effects, including cancers.

A U.S. retrospective epidemiological study, reported in 1980, tried without luck out to pin down whether DES exposure was a risk factor in testicular cancer. The researchers reported in dismay that "the specific type of medication ... is unknown" in about half the men with testicular cancer and in about half the controls because of poor and short-term record-keeping by doctors, hospitals and pharmacies.

Another U.S. study, reported in 1984, came to the conclusion that the relative lack of case reports of testicular cancer from DES sons "undoubtedly reflects ignorance of DES exposure among young men rather than a reduction in cancer occurrence."

And, ironically, although $1 million of the $6 million U.S. government grant money will be spent on public and physician education about DES and health effects in sons, none of that money will be spent on original research into whether or not DES causes cancer in men. Sons will not be completely ignored. Some of the grant money will be spent on research involving sons; the U.S. National Cancer Institute is under-taking a huge survey of DES mothers, daughters, and sons, looking for wide range of health problems.

But, for now, the cancer question will remain unanswered; Michael Du Bow and Bryce Osborne will be left with good guesses and unanswered questions. ' Perhaps, as more DES-exposed men come forward reporting their health effects, funding agencies will see the need to answer the sons' cancer questions, and the research will begin.