Non-smoking-related cancers on rise.

Despite an all-out war on cancer over the past 20 years, people are developing malignancies at a higher rate than ever before -- even after accounting for smoking and the fact that people are living longer, a new study finds: These increased rates appear highest in the youngest group analyzed -- "baby boomers" born between 1948 and 1957.

"The good news is that improved therapies have reduced cancer mortality in persons younger than 45... [and] lowered cardiovascular mortality in persons of all ages," conclude Devra Lee Davis of the Department of Health and Human Services and her co,workers in the Feb. 9 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION. "The bad news," they add, "is that in all age groups, cancer incidence is increasing in Sweden and the United States and that few new, effective treatments have been devised for the most common cancers."

Davis' team broke down, by age, data on cancer incidence and mortality among U.S. whites between 1973 and 1987. They then compared cancer rates among age groups, beginning with the group born between 1888 and 1897. To offset the effects of smoking, the researchers analyzed separately data on all cancers, female breast cancers, smoking-related cancers (defined as those of the mouth, larynx, lung, pharynx, and esophagus), and all nonsmoking-related cancers.

During the 15 years ending in 1987, cancer deaths fell 17 percent among persons under age 55, while rising 12 percent in those 55 and over. However, the analyses also suggest that, compared to men born before 1898, male baby boomers faced twice the overall cancer risk (136 per 100,000 in 1987, for instance) and more than twice the rate of non-smoking-related cancers (124 per 100,000). Female baby boomers developed 50 percent more cancers overall than women born in the late 19th century -- 216.5 per 100,000 in 1987 -- and 30 percent more non-smoking-related cancers.

Female breast cancer rates have continued to climb steadily in all age groups, Davis and her co-workers note, with baby boomers developing 2.7 times more such malignancies than their grandmothers born in the 1890s.

These analyses argue that U.S. residents face a growing cancer risk from some as-yet-unidentified environmental factors, Davis says. "I think there is an interesting parallel with farmers," Davis told SCIENCE NEws. Compared to the general population, farmers die more often of certain types of tumors -- such as prostate and brain cancers and non-Hodgkin's lymphoma. The incidence of these cancers is beginning to rise in the general population, she notes, which suggests that some common exposure, "such as solvents, pesticides, engine exhausts, fuels, sunlight, or animal viruses," may play a role.

However, Anthony B. Miller of the University of Toronto cautions in an editorial in the same journal that because most cancers analyzed here "would have had their origin many years ago," their causes may already be recognized and controlled, as asbestos now is.