The etiological factors are smoking, . Occupational and environmental exposures (by-products of aluminum products, arsenic, asbestos, bis-chloromethylether, chromium compounds, coke ovens, mustard gas, nickel-containing impurities, vinyl chloride. Long-term exposure to beryllium, cadmium, silicon, formalin, etc.), ionizing radiation. Pre-existing chronic lung infections (e.g., patients with tuberculosis, bronchiectasis, etc.), genetic and other factors, atmospheric pollution.
The clinical manifestations are complex, and the presence or absence, severity and early or late appearance of symptoms and signs depend on the site of tumor occurrence, pathological type, presence or absence of metastasis and complications, as well as the differences in the degree of response and tolerance of patients. Early symptoms of lung cancer are often mild and may even be uncomfortable. The symptoms of central lung cancer appear early and heavy, while the symptoms of peripheral lung cancer appear late and light, or even asymptomatic, and are often detected during physical examination. The symptoms of lung cancer are broadly divided into: local symptoms, systemic symptoms, extra-pulmonary symptoms, infiltration and metastasis symptoms. Local symptoms refer to the symptoms caused by irritation, obstruction, infiltration and compression of tissues when the tumor itself grows locally, such as cough, blood in sputum or hemoptysis, chest pain, chest tightness, shortness of breath, hoarseness, etc. Systemic symptoms include fever, wasting and cachexia. Extrapulmonary symptoms include pulmonary osteoarthrosis, which mainly manifests as crural finger (toe), distal periosteal hyperplasia of long bones, new bone formation, swelling, pain and tenderness of affected joints. ectopic insulin secretion syndrome, carcinoid syndrome, neuromuscular syndrome (Eaton-Lambert syndrome), ectopic growth hormone syndrome, and abnormal antidiuretic hormone secretion syndrome. Other manifestations such as skin lesions (acanthosis nigricans, dermatitis, skin pigmentation, scleroderma, palmoplantar skin hyperkeratosis, etc.), cardiovascular system (wandering venous embolism, phlebitis and non-bacterial embolic endocarditis), hematological system (chronic anemia, purpura, erythrocytosis, leukemia-like reaction). External invasive and metastatic symptoms, . Lymph node metastases (most commonly mediastinal and supraclavicular lymph nodes), pleural invasion and/metastases, . Superior Vena Cava Syndrome (SVCS) renal metastases, GI metastases, bone metastases, CNS symptoms (brain, meningeal and cremaster metastases, encephalopathy and cerebellar cortical degeneration), cardiac invasion and metastases, peripheral nervous system symptoms (Horner’s syndrome, Pancoast’s syndrome, etc.).
Diagnosis.
1.X-ray examination, the site and size of lung cancer can be understood by X-ray examination, and local emphysema, pulmonary atelectasis or infiltrative lesions in the adjacent parts of the lesion or inflammation of the lung due to bronchial obstruction may be seen.
2.Bronchoscopy, through bronchoscopy, the lesions of bronchial lining and lumen can be directly observed. Tumor tissues can be taken for pathological examination or bronchial secretions can be aspirated for cytological examination to clarify the diagnosis and determine the histological type.
3.Cytological examination, sputum cytological examination is a simple and effective method for lung cancer screening and diagnosis, and most patients with primary lung cancer can find shed cancer cells in sputum. The positive rate of sputum cytology examination for central type lung cancer can reach 70% to 90%, while the positive rate of sputum examination for peripheral type lung cancer is only about 50%.
4.Thoracotomy, if the nature of the lung mass is not clear after multiple examinations and short-term diagnostic treatment, and the possibility of lung cancer cannot be excluded, a thoracotomy should be performed. This can avoid delaying the disease and losing the opportunity of early treatment for lung cancer patients.
ECT examination, ECT bone imaging can detect bone metastases at an earlier stage, and both X-ray and bone imaging have positive findings, if the osteogenic reaction of the lesion is quiescent and metabolism is not active, then bone imaging is negative and X-ray is positive. It should be noted that the false-positive rate of ECT bone imaging in diagnosing bone metastasis of lung cancer can reach 20%-30%, so those who have positive ECT bone imaging need to have MRI scan of the positive area of bone.
Mediastinoscopy is mainly used for patients with mediastinal lymph node metastasis, who are not suitable for surgical treatment and cannot be diagnosed pathologically by other methods. Mediastinoscopy should be performed under general anesthesia. A transverse incision is made in the superior sternal recess, the anterior soft tissues of the neck are bluntly separated to reach the anterior tracheal space, the anterior tracheal passage is bluntly freed, and a viewing scope is placed to slowly pass behind the innominate artery to observe the enlarged lymph nodes in the paratracheal, tracheobronchial angles and under the bulge. The diagnosis of primary bronchopulmonary cancer is based on symptoms, physical signs, imaging manifestations and sputum cancer cell examination.
Differential diagnosis.
Typical lung cancer is easily recognized, but in some cases, lung cancer is easily confused with
1. tuberculosis. Tuberculosis, especially tuberculoma (ball), should be distinguished from peripheral type lung cancer. Tuberculoma (sphere) is more often seen in young patients with a long course of disease, rarely seen with blood in the sputum and tuberculosis bacteria found in the sputum. They are mostly round on imaging, found in the apical or posterior segments of the upper lobes, small in size, not exceeding 125 px in diameter, with smooth borders and calcifications visible in the density heterogeneity. Tuberculomas (spheres) are often surrounded by scattered tuberculosis foci called satellite foci. Peripheral lung cancer is mostly seen in patients over 40 years old, with blood in the sputum, and sputum positive for cancer cells in 40% to 50% of cases. In some cases of chronic tuberculosis, lung cancer may occur on the basis of tuberculosis, further sputum cytology and bronchoscopy must be done, and if necessary, thoracotomy should be performed.
Pulmonary infection is sometimes difficult to distinguish from obstructive pneumonia caused by obstructed bronchus of lung cancer. However, if pneumonia occurs in the same area for several times, it should be alerted and tumor blockage should be highly suspected. Sputum should be taken from the patient for cytological examination and fiber optic light-guided bronchoscopy.
Benign tumors of lung, such as structural tumor, chondrosarcoma and fibroma are rare, but they must be distinguished from peripheral lung cancer. Bronchial adenoma is a kind of low-grade malignant tumor, which often occurs in young women. Therefore, it often has clinical symptoms such as lung infection and hemoptysis, and can be diagnosed by fiberoptic bronchoscopy.
4. Mediastinal malignant lymphoma (lymphosarcoma and Hodgkin’s disease) often has clinical symptoms such as cough and fever, and imaging shows widened mediastinal shadow with lobar shape, which is sometimes difficult to distinguish from central lung cancer. If there are enlarged supraclavicular or subaxillary lymph nodes, biopsy should be performed to clarify the diagnosis. Lymphosarcoma is particularly sensitive to radiation therapy, and small doses of radiation therapy can be tried for suspicious cases, which can result in significant shrinkage of the mass. This experimental treatment can help in the diagnosis of lymphosarcoma.
Treatment.
(a) Chemotherapy. In recent years, the role of chemotherapy in lung cancer is no longer limited to patients with inoperable advanced lung cancer, but is often included in the comprehensive treatment plan of lung cancer as systemic treatment, divided into therapeutic chemotherapy and adjuvant chemotherapy.
(b) Radiation therapy has the best efficacy for small cell lung cancer, followed by squamous cell carcinoma and the worst for adenocarcinoma. It is divided into radical treatment, palliative treatment, preoperative neoadjuvant radiotherapy, postoperative adjuvant radiotherapy and intracavitary radiotherapy according to the purpose of treatment.
(3) Surgical treatment of lung cancer: Surgery is the first and main treatment method for lung cancer, and the only treatment method that can cure lung cancer. The objectives of surgical treatment for lung cancer are: to completely remove the primary lesions and metastatic lymph nodes of lung cancer to achieve clinical cure; to remove most of the tumor to create favorable conditions for other treatments, i.e., subtotal surgery; subtotal surgery: suitable for a small number of patients, such as refractory pleural cavity and pericardial effusion, to cure or relieve clinical symptoms caused by pericardial and pleural effusion by removing pleural and pericardial implantation nodes and removing part of pericardium and pleura The procedure is designed to prolong life or improve quality of life by removing a portion of the pericardium and pleura to cure or relieve clinical symptoms caused by pericardial and pleural effusion. Decompression surgery requires both local and systemic chemotherapy. Surgical treatment often requires preoperative or postoperative adjuvant chemotherapy and radiotherapy to improve the cure rate of surgery and patient survival. The five-year survival rate of lung cancer surgical treatment is 30%-44%; the mortality rate of surgical treatment is 1%-2%.
1.Surgical indications.
Surgical treatment of lung cancer is mainly suitable for early and middle stage (stage I-II) lung cancer, stage IIIa lung cancer and partially selective stage IIIb lung cancer with tumor confined to one side of the chest.
(1) Stages I and II lung cancer.
(2) Stage IIIa non-small cell lung cancer.
(3) Partial stage IIIb non-small cell lung cancer with lesions confined to one side of the chest cavity that can be completely resected.
(4) Patients with stage IIIa and some stage IIIb lung cancers that have been downgraded after preoperative neoadjuvant chemotherapy
(5) Non-small cell lung cancer with isolated metastases (i.e. intracranial, adrenal or hepatic), if both the primary tumor and metastases are suitable for surgical treatment and there are no contraindications to surgery and complete resection of the primary tumor and metastases can be achieved
(6) Non-small cell stage IIIb lung cancer with a clear diagnosis, where the tumor invades the pericardium, large blood vessels, diaphragm, and tracheal ramus, where distant or/and micrometastases have been excluded by various examinations, where the lesion is limited, where the patient has no physiological contraindications to surgery, and where complete resection of the tumor-invaded tissue and organs can be achieved.
2. Contraindications to surgery.
(1) Stage IV lung cancer with existing extensive metastases.
(2) Patients with multiple fused mediastinal lymph node metastases, especially invasive mediastinal lymph node metastases.
(3) Stage IIIb lung cancer with contralateral hilar or mediastinal lymph node metastases.
(4) Those with severe visceral insufficiency that cannot tolerate surgical procedures.
(5) Those who suffer from bleeding disease and cannot be corrected.
3. Selection of surgical procedure for lung cancer.
The principles of surgical resection are: complete removal of the primary foci and lymph nodes with potential metastasis in the chest cavity, and preservation of normal lung tissues as much as possible; total lung resection should be done with caution.
(1) Lung wedge and partial resection refers to wedge-shaped cancer block resection and partial lung segment resection. It is mainly suitable for early stage lung cancer with small volume, old and frail, poor lung function or low malignancy of well differentiated cancer.
(2) Pulmonary segmental resection It is the resection of anatomical lung segments. It is mainly suitable for isolated early lung cancer of peripheral type with poor cardiopulmonary function, or partial central lung cancer with limited lesions located at the root of the lung cancer.
(3) lobectomy lobectomy is suitable for peripheral type and partially central type lung cancer whose lung cancer is confined to one lobe, and central type lung cancer must ensure that no cancer remains in the bronchial stump. If the lung cancer involves both lobes or the middle bronchi, two lobectomies in the upper or lower middle lobe are feasible.
(4) Bronchial sleeve shaped lobectomy This procedure is mainly suitable for central type lung cancer where the lung cancer is located in the bronchi of the lobe or the opening of the middle bronchi. This procedure has the advantage of achieving complete resection of the lung cancer while preserving healthy lung tissue.
(5) Bronchopulmonary artery sleeve shaped lobectomy This type of surgery is mainly suitable for central type lung cancer in which the lung cancer is located in the bronchi of the lobe or the opening of the middle bronchi and the lung cancer also invades the pulmonary artery trunk. In addition to bronchial resection and reconstruction, it is also necessary to perform resection and reconstruction of the pulmonary artery trunk at the same time. The advantage of this procedure is that it achieves complete resection of the lung cancer while preserving healthy lung tissue.
(6) Tracheal rung resection and reconstruction When the lung tumor exceeds the main bronchus involving the rung or the lateral wall of the trachea but does not exceed 50px, tracheal rung resection and reconstruction or sleeve total pneumonectomy can be performed, and if a lobe of the lung is still preserved, tracheal rung resection and reconstruction with preservation of the lobe should be strived for.
(7) Total pneumonectomy Total pneumonectomy refers to the whole lung on one side, i.e. right or left side total pneumonectomy, and is mainly suitable for lung cancer with good cardiopulmonary function, more extensive lesions and younger age, which is not suitable for lobectomy or sleeve lobectomy. The complication rate and mortality rate of total pneumonectomy are higher, and the long-term survival rate and quality of life of patients are not as good as lobectomy, so the indications for surgery should be strictly grasped.
4.Surgical treatment of recurrent lung cancer.
Recurrent lung cancer includes the recurrence of local residual cancer after surgery and the new occurrence of second primary lung cancer in the lung. For the recurrence of residual cancer of bronchial stump, re-operation should be pursued and bronchial sleeve molding should be performed to remove the residual cancer. For the second primary lung cancer occurring after complete lung cancer resection, as long as the lung cancer is suitable for surgical treatment, the patient’s visceral function can tolerate reoperative treatment, and there are no surgical technical problems, reoperation to remove the recurrent lung cancer should be considered.
Prevention
Lung cancer can be prevented and controlled. Studies have shown that the incidence and mortality rate of lung cancer in western countries have decreased significantly in recent years through tobacco control and environmental protection. The prevention of lung cancer can be divided into three levels of prevention: primary prevention is the etiological intervention; secondary prevention is the screening and early diagnosis of lung cancer to achieve early diagnosis and treatment of lung cancer; and tertiary prevention is the rehabilitation prevention.