张先生是一位老烟民,从17岁时学会抽烟开始,已经有46年的烟龄了。他经常咳嗽,近几年来咳嗽时痰中偶尔还带点血丝,因此他常常担心自己的肺部有问题。不过幸好单位每年都组织体检,每次体检他都拍胸片,从未发现肺部有问题。但是今年,体检结束还不到3个月,他不仅咳嗽加重,还出现了胸部胀痛、声嘶、气促等症状,急忙到医院就诊,医生怀疑是肺癌,就让他做了个肺部CT。结果显示纵膈后方有一个2厘米大小的肿块,手术切除后,病理确诊为肺鳞癌。张先生和家人非常疑惑,为什么每年都做健康体检,却没查出来问题呢? Mr. Zhang is an old smoker who started smoking when he was 17 and has been 46 years old. He often coughs. In sputum he has occasionally had some bloodshot sputum during his coughing in recent years, so he often worried about problems in his lungs. However, fortunately, the unit organizes physical examinations every year. He takes chest radiographs for each physical examination and never finds problems with the lungs. But this year, less than three months after the physical examination ended, he not only had a worsening cough, but also had symptoms such as chest pain, hoarseness, and shortness of breath. He rushed to the hospital for treatment. The doctor suspected lung cancer and let him have a lung. CT. The results showed that there was a 2 cm mass behind the mediastinum. After surgical resection, the pathology was diagnosed as lung squamous cell carcinoma. Mr. Zhang and his family are very puzzled. Why did they not check out the health examination every year?