癌症严重威胁人类的生命和健康。据世界卫生组织估算，全世界每年的癌症患者为59O万，死于癌症的人数为43O万。预计到2000年，每年死于癌症的人数将增至800万。我国70年代中期，每年约有70万人死于癌症，80年代中，每年死于癌症的人增至90万．如不积极防治，估计到2000年，我国 Cancer is a serious threat to human life and health. According to estimates by the World Health Organization, the number of cancer patients in the world is 5.9 million annually and the number of people who die of cancer is 4.3 million. It is estimated that by 2000, the number of people who die of cancer each year will increase to 8 million. In the mid-1970s, about 700,000 people died of cancer each year in the country. In the mid-1980s, the number of people who died of cancer each year increased to 900,000. If not actively prevent and control, it is estimated that by 2000, China