(I) Incidence rate and epidemiology
The overall incidence of lung cancer in China is on the rise, and there are differences in incidence rates between urban and rural areas. Epidemiology shows that men have a higher incidence rate than women, which may be related to smoking, while women have a higher mortality rate due to adenocarcinoma.
(II) Etiology
About 87% of lung cancers are related to smoking, and there is a significant positive dose-intensity correlation between smoking and lung cancer, and passive smoking increases the risk of the disease. About 6% of lung cancers are attributed to radon, which is currently considered to be the second cause of lung cancer. About 3% to 4% of lung cancer is attributed to asbestos exposure. Chronic lung diseases and tuberculosis increase the risk of the disease. In addition, individual genetic susceptibility is also involved in the occurrence of tumor.
(C) Histological staging and clinicopathological features
Clinically, lung cancer is widely classified into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC).
Pathologically, squamous carcinoma is the most common, central type is common, easily metastasized to regional lymph nodes, and is the most common cavity of all kinds of lung cancer.
Adenocarcinoma is commonly seen in nonsmokers, former smokers, and is also the most common pathological type in female patients; it is mostly of the peripheral type and is highly susceptible to regional lymph node metastases and distant metastases.
Large cell lung cancer is less differentiated than squamous and adenocarcinoma, and similar to adenocarcinoma, it is prone to regional lymph node metastasis and distant metastasis. Necrosis but no cavities are common.
SCLC is 95% attributable to smoking and most of it is central. The typical presentation is a large central primary lesion with extensive metastases in the hilum and mediastinal lymph nodes, and about 2/3 have distant metastases at the time of diagnosis.
(IV) Symptoms and signs
Lung cancer can be asymptomatic in the early stage, and the most common symptoms at the time of diagnosis are wasting, cough, shortness of breath, weakness, hemoptysis and chest pain in order. The clinical manifestations of lung cancer are complex and broadly divided into.
1, primary tumor: it can cause cough, hemoptysis, dyspnea, chest pain, wheezing, etc.
2, intra-thoracic spread of tumor: it may lead to hoarseness, phrenic nerve palsy, dysphagia, superior vena cava compression syndrome, pleural effusion, pericardial effusion, Pancost syndrome, etc.
3. distant metastasis: including brain metastasis, bone metastasis, adrenal metastasis and clinical symptoms related to metastasis from other organs.
4.Extrapulmonary manifestations.
(V) Diagnosis
1, medical history and physical examination.
2.Non-invasive examination: X-ray, CT, MRI, PET and PET-CT.
3.Histological diagnosis: sputum cytology, fiberoptic bronchoscopy, CT-guided incisive aspiration biopsy, etc.
4.Tumor markers.
5.Isolated pulmonary nodules
(VI) Treatment
SCLC: chemotherapy as the standard treatment for the extensive stage, and radiotherapy combined as the standard treatment for the limited stage.
NSCLC: surgical resection combined with postoperative chemotherapy, and curative radiotherapy for unresectable cases.