In the modern world, no branch of the human family tree is known to be free of cancer, though rumors to the contrary keep popping up. In 1977 for example, the United Nations Educational, Scientific and Cultural Organization reported that the people of Pakistan's remote Hunza Valley showed no signs of the disease. The UN report was proved wrong; the Hunzas have insignificantly fewer cases of cancer than other populations of similar size, environment and occupation. Farmers in the uplands of Soviet Georgia - near the black sea - have long been an even richer source of health myth. They were once said to be not only cancer-free, but even immune to the aging process; tales abounded of people still active at the age of 125. But the accounts of fantastic longevity turned out to be based on provincial chauvinism and bad record-keeping. And the Soviet government, after an intensive study of the Georgians, reported in 1980 that they suffer as much breast, lung and cervical cancer as other Soviet peoples; in fact, only the incidence of stomach and esophageal cancer proved substantially lower than the average.
The facts about the Soviet Georgians illustrate an important truth about cancer. Although the affliction is universal, there are strange variations in its incidence, as a whole and by type. World Health Organization statistics showed that in 1974 and 1975 Scotland had a higher cancer death rate than any other country in the world - more than five and a half times higher than that of Thailand, the country with the fewest cases. Variations among types of cancer were even wider. Japan and Norway had much the same total cancer death rates, but the Japanese suffered three times more stomach cancer than the Norwegians; on the other hand, the death rate from breast cancer among Norwegian women was nearly four times higher than among the women of Japan.
Scientists can explain some of the variations in cancer incidence, including the appalling rate of stomach cancer in Japan. They are virtually certain that the Japanese diet, high in smoked and salted foods and in known carcinogen called bracken fern, is a major cause of that cancer. Elsewhere, specific cancers have been attributed to specific foods and other agents. But anomalies and mysteries remain. No one yet knows, for example why the cancer death rate is highest in Scotland. And no one knows why the breast cancer death rate is higher in Norway than in Japan, though some scientists have suggested that differences in childbearing or breast feeding customs may be the key.
