医学补充阅读：Child cancer rate is increasing

　　friday, december 10, 2004

　　london, dec 10, 2004 (united press international via comtex) —— the rate of childhood cancer has increased steadily over the last three decades, according to a report by french scientists published in the lancet.

　　the international agency for research on cancer examined data from 19 european countries.

　　the agency, based in france, found that cancer rates increased by around 1 percent a year for children and 1.5 percent a year for adolescents between the 1970s and 1990s, the bbc reported friday.

　　the scientists said no single factor can be held responsible for the rise, and the underlying causes are likely to be highly complex.

　　however, they suggested that exposure to infections and changes in birth weight may play a role, as may the mixing of different populations.

　　some —— but not all —— of the rise might be explained by better diagnosis of the disease, and better record keeping.

　　the increases were recorded for virtually all tumor types in children.

　　survival rates increased substantially over the three decades of the study, reaching a five-year survival rate of 75 percent for children in western europe and 64 percent in eastern europe. survival rates for adolescent patients were similar.英语口语