在我们生存的环境中存在着各种致癌因素,但并非接触致癌因素的人都罹患癌症。事实上,在癌症的高发区,患病的人也不过0.1—0.2%。我们知道,吸烟是引起肺癌的重要因素,吸烟者的肺癌发生率明显高于不吸烟者。吸烟愈多,时间愈长,发生肺癌的可能性也愈大。但是,却有相当一部分吸烟者,甚至是严重吸烟者,的确没有 There are various carcinogenic factors in the environment we live in, but people who are not exposed to cancer cause cancer. In fact, in the high-incidence areas of cancer, the number of people suffering from the disease is only 0.1-0.2%. We know that smoking is an important factor that causes lung cancer. The incidence of lung cancer among smokers is significantly higher than that of non-smokers. The more smoking, the longer the time, the greater the possibility of developing lung cancer. However, there are quite a few smokers, even serious smokers.