Chemicals exposure-cancer link

[Ah Hai]

PARIS - WORKPLACE exposure to synthetic fibres and certain oil byproducts before her mid-30s triples a woman's risk of breast cancer after menopause, a study among Canadian patients said on Thursday.

France Labreche of the National Institute of Public Health in Montreal led an investigation into the health records of 1,169 women aged 50 to 75. Just under half had been diagnosed with breast cancer in 1996 and 1997, after having undergone menopause. The other 613 women were diagnosed during the same period with other forms of cancer and acted as a comparison.

A squad of chemists and industrial hygienists probed the extent to which all the women had been exposed to about 300 different substances throughout their working life. After filtering out other known causes of breast cancer, they found a strong link between higher rates of risk and exposure to several common synthetic materials, found in textile factories and other industrial settings.

Compared to the non-breast cancer group, the risk peaked before the age of 36, when still-active cells in breast tissue are thought to be more sensitive to harmful chemicals. Women occupationally exposed to acrylic fibres ran a seven-fold risk of breast cancer, while exposure to nylon fibres nearly doubled the risk.

Among breast cancer patients, those whose tumours responded well to oestrogen treatment, but not progesterone treatment, were more than twice as likely to have breast cancer for every decade they were exposed to so-called monaromatic hydrocarbons - a byproduct of crude oil - and to acrylic or rayon fibres. Oestrogen and progesterone are both naturally-occurring hormones used in breast cancer treatment. Exposure before the age of 36 to another class of hydrocarbons found in petroleum products tripled the risk for women whose tumours responded to both types of hormone treatment.

The authors concede that the results are not conclusive, but point out that they are consistent with the theory that breast tissue is more susceptible to chemical toxins in women under 40. They also note the rising rate of breast cancer in rich countries, which could also be due to earlier and better diagnosis and increased rates of alcohol consumption. -- AFP

 

[Ah Hai]

Prostate drug cuts cancer risk

WASHINGTON - A DRUG commonly used to shrink enlarged prostates in men has been found to also cut the risk of developing cancer in the same glands, a new study said.

The four-year international study of the drug, dutasteride, showed that it reduced by 23 per cent the risk of being diagnosed with prostate cancer in men with an increased chance of developing the disease. Such tumours account for the majority of all prostate cancers and grow unpredictably, causing many men to opt for aggressive surgery or radiation treatments which can leave them incontinent or impotent.

'Dutasteride may potentially offer many thousands of men a way to reduce their risk of being diagnosed with prostate cancer,' said the lead author, Gerald Andriole, chief of urologic surgery at Washington University School of Medicine in St. Louis. 'This means more men could avoid unnecessary treatment for prostate cancer along with the costs and harmful side effects that can occur with treatment.'

The trial of the drug was carried out in 250 sites in 42 countries involving some 8,231 men aged between 50 to 75, who were randomly given either a placebo or a daily dose of the drug. Two years after the start of the trials, and then four years after, the men were given biopsies, said the study published in Thursday's issue of the New England Journal of Medicine.

Some 659 men or 19.9 per cent taking dutasteride were diagnosed with prostate cancer, compared to 858 men or 25.1 per cent taking a placebo. None of the men in the study died of prostate cancer. Among men with a family history of prostate cancer, the drug reduced the relative risk of a prostate cancer diagnosis by 31.4 per cent.

'The most likely explanation for the study's results is that dutasteride is keeping tumors small or even shrinking them to the point that they are unlikely to be detected by a biopsy,' said Dr Andriole, who also treats patients at Barnes-Jewish Hospital and the Siteman Cancer Center. Dutasteride was most effective at reducing the risk of medium-grade tumours. The study was funded by GlaxoSmithKline, the manufacturer of Avodart, which is the brand name of the drug. -- AFP

 

[ps07857]

Dutasteride is Avodart. Figures of 23% reduction is only a marginal imporvement. For all you know, it may just be a coincidence.