The poor prognosis of lung cancer patients The length of survival is related to factors such as tumor cell type, site, size and whether there are distant metastases at the time of detection, acceptable treatment methods and modalities, and the immunological interactions between the host and the cancer. Non-small cell carcinoma consists of three types of carcinomas: squamous cell carcinoma, adenocarcinoma and large cell undifferentiated carcinoma, which account for 80% of all lung cancers. In the past 20 years, the incidence of these three types of cancer has changed, and now adenocarcinoma has jumped to the top, accounting for 35%, squamous cell carcinoma for 30%, and large cell carcinoma for 10%-15%. When lung cancer is detected, 55% of the cases have distant metastasis, 30% have local lymph node metastasis, and 15% of the cases are still confined to the lung, which can be cured if resected. If lung cancer is found without treatment, 90% of cases will die within one year. For those cases with extra-thoracic metastases or extensive local lesions without indications for thoracotomy, the prognosis is very poor and most of them die within six months. In cases with brain, liver, or contralateral lung metastases, all but a few die within 3 months. When bone metastases are present, the survival time is slightly longer, but almost all of them die within 1 year. When the cancer spreads to the pleura and malignant pleural effusion appears, only 20% can survive for six months. Those with extra-thoracic non-metastatic symptoms usually have poor prognosis Especially when there are endocrine function abnormalities, almost all of them are caused by small cell carcinoma except hypercalcemia and sex hormone function abnormalities. Patients with pulmonary hypertrophic osteoarthropathy have a high resection rate, but also have a poor prognosis, with 88% of cases dying within 3 years after surgery. Patients who can undergo lung resection, 2/3 of them will survive for 1 year, about 1/2 for 2 years, more than 1/3 for 3 years and 1/4 for 5 years. Whether lung cancer can be detected early is decisive for prognosis. Central lung cancer: It originates in the central part of the lung. Its symptoms include irritating cough and blood in sputum (which can be in the form of blood, blood spots or mixed with sputum). After the tumor gradually increases in size, fever, chest tightness and breath-holding sensation may appear. Since this kind of lung cancer is located in the central part of the lung, this sheer shadow is often hidden by the shadow of the heart and large blood vessels, so the chest X-ray examination alone may easily cause misdiagnosis. The best examination methods include fine plethysmographic examination of sputum, tomography of trachea and bronchus, CT examination, bronchoscopy, mediastinography, and fiberoptic bronchoscopy. Peripheral type lung cancer: It originates in the periphery of the lung, so it seldom produces symptoms such as cough and hemoptysis. A few patients may have hidden pain, dull pain or intermittent pain in the chest, but when the tumor increases and invades the pleura and chest wall, it may produce localized continuous severe pain or stabbing pain in the chest. Since peripheral lung cancer is in the periphery of the lung, it can be easily detected by chest X-ray, and its diagnosis mainly relies on chest X-ray, tomography and local puncture for pathological examination. However, peripheral lung cancer still lacks characteristic X-ray signs in early stage, therefore, many patients may be misdiagnosed as tuberculosis or inflammation of the lung for a long time and delay treatment. In order to avoid misdiagnosis, patients above 40 years old who suddenly develop round shadow in the lung and cannot be diagnosed as tuberculosis should be treated with surgery or dynamic observation for 1-2 months at an early stage. If the round shadow gradually increases or there is no obvious change after drug treatment, it should never be delayed any longer, but should be quickly examined by a thoracic surgeon for early surgery. In addition to the lung symptoms mentioned above, patients with lung cancer also have many extra-pulmonary symptoms, such as enlarged breasts in men, male feminization, phlebitis, pestle and mortar finger and hypertrophic osteoarthropathy, and endocrine dysfunction. Therefore, any unexplained pestle finger and toe as well as hypertrophic osteoarthropathy should be examined by chest X-ray to exclude the possibility of lung cancer.