肺癌为当前世界各地最常见的恶性肿瘤,发病率在多数国家仍在升高。据世界卫生组织2000年报告,1997年全世界死于癌症的共706.5万,占总死亡数的12.6%,其中肺癌占癌症死亡的19%。在我国肺癌在城市中占常见恶性肿瘤的首位,在农村占第三位,发病率也有明显增高的趋向,已经引起广泛的 Lung cancer is the most common malignancy in the world today, and the incidence is still rising in most countries. According to the World Health Organization’s 2000 report, a total of 7.065 million people died of cancer in 1997 worldwide, accounting for 12.6% of the total number of deaths, of which lung cancer accounts for 19% of cancer deaths. In our country, lung cancer occupies the first place in the city which is the common malignant tumor, occupies the third place in the rural area, the morbidity also has the tendency to be obviously increased, has already caused the widespread