在世界范围内,结直肠癌是位居第四的恶性肿瘤。2002年全球结直肠癌共发生约100万例,死亡53万例。在美国,结肠癌在与癌症相关的死亡中是第二大致死疾病。我国结直肠癌发病率有上升趋势,据2000年调查结果显示,在我国北京和上海等大城市结直肠癌的发病率已上升至第2位或第3位。目 Colorectal cancer is the fourth most malignant tumor in the world. In 2002, there were about 1 million cases of colorectal cancer worldwide and 530,000 deaths. In the United States, colon cancer is the second most lethal disease among cancer-related deaths. The incidence of colorectal cancer in our country has an upward trend. According to the survey results in 2000, the incidence of colorectal cancer in major cities such as Beijing and Shanghai in our country has risen to No. 2 or No. 3. Head