The sharp increase in cancer rates in recent decades isn't due only to an accident of genetics or lifestyle choices such as smoking, drinking or eating fatty foods, a leading medical researcher says.

Samuel Epstein, professor of occupational and environmental medicine at the University of Illinois, says three-quarters of the rise in U.S. cancer cases can be attributed to exposure to carcinogens in the environment, workplaces, food, cosmetics and consumer products.

Dr. Epstein is sometimes viewed as a heretic in the international cancer-research community for arguing that the best way to fight the disease is to prevent cancers by cleaning up the environment.

In contrast, most major cancer organizations. such as the Canadian Cancer Society, focus their efforts mainly on drug treatments or cures. The society also blames lifestyle choices for 60 per cent to 70 per cent of cancers.

Dr. Epstein will dispute what he calls these "blame-the-victim" approaches, at a workshop on cancer prevention at McMaster University in Hamilton today.

The rise in cancer rate "can't be explained on the basis of so-called-blame-the-victim strategies and policies Dr Epstein said in a recent interview.

He said U S. cancer rates, adjusted for the aging population, have risen about 55 per cent since the 1950s but that only about one quarter of the increase can be attributed to smoking. He attributes the rest of the increase to exposure to cancer-causing substances such as solvents and other petrochemical products, dyes, pesticides, and radiation.

There is an overwhelming body of scientific information on the causal association between cancels and the involuntary and avoidable exposures to carcinogens, in the air, in water, in food, in household products and cosmetics he said. "The cancer epidemic is a reflection of uncontrolled runaway industrial technologies.

The other evidence pointing to environmental causes is the fact that childhood rates of cancer have also been increasing, as well as research findings tumors in wildlife, such as beluga whales in the St. Lawrence River

It is difficult to link cancer and lifestyle choices, such as smoking, sunbathing and fatty food. to activities by children and wildlife.

Dr. Epstein also questions what he calls the "overwhelming preoccupation of the cancer establishment" with the search for genetic explanations for the illness

He said genetics factors are identified as the cause of only about 5 per cent to 10 per cent of breast cancers, leaving the balance to other causes. in addition, he said, the human gene pool has not changed substantially in the past hall-century, in which cancer rates have soared.

For instance, Dr. Epstein said, many research studies have concluded that no link exists between breast cancer and fatty diets. He said a more promising approach would be to try to study whether carcinogens inadvertently contained in the fat are responsible. Cancer-causing substances, such as dioxins from the burning of plastics and other industrial sources are extremely soluble in fat and that might explain some cases of cancer.

Dr. Epstein agrees that the single most important way to prevent cancer would be to end tobacco use, but he said smoking rates and consequently lung cancers from this source have peaked in men and are already declining.

He said a promising step in cancer prevention would be the policy makers to order a phasing out of toxic and carcinogenic substances.

Another action, he suggested would be to ensure that newly created substances do not cause cancer by requiring corporations to prove that their products are harmless rather then making the public or government prove that their are carcinogenic once they are in the marketplace