Nuclear work is linked to cancer of prostate

(First Edition)

WORKERS in the nuclear industry who are exposed to certain radioactive substances have an increased risk of prostate cancer, according to a study - the first to show a definitive link between occupational exposure and a type of cancer.

Men who had worked in areas where they might have been exposed to the isotopes were 2.5 times more likely to develop prostate cancer, and men known to be contaminated were 5 times more likely to develop it. Five radioactive substances were associated with an increased risk: tritium, chromium-51, iron-59, cobalt-60, and zinc-65.

The researchers from the London School of Hygiene and Tropical Medicine, and the Imperial Cancer Research Fund, looked at 136 cases of prostate cancer in employees of the United Kingdom Atomic Energy Authority, diagnosed between 1946 and 1986.

According to the report in tomorrow's British Medical Journal, 10 per cent had definite internal contamination by at least one of the five substances, and 20 per cent had worked in places which could have been contaminated.

Dr Valerie Beral, head of the ICRF cancer epidemiology unit at Oxford, said that the cancer occurred at an earlier age than usual.

'Six out of the 14 known to have been contaminated were in their forties or fifties when they were diagnosed, which is unusual. We also found that the risk increased the longer men worked in places that were potentially contaminated by these radioactive substances. We do not know whether the risk falls when workers leave.'

The substances linked with prostate cancer are produced by the irradiation of steel casing or piping, or from moderator fluid of heavy water reactors. All heavy water research reactors have now closed.