I. Overview of lung cancer
Lung cancer occurs in the bronchial mucosa epithelium and is also called bronchopulmonary cancer. Lung cancer generally refers to cancer of the parenchyma of the lung. Lung cancer is currently the number one cause of cancer deaths worldwide. 600,000 people died of lung cancer in 1995 and the number is increasing every year. The incidence of lung cancer in women in particular is on the rise.
The distribution of lung cancer is more in the right lung than the left lung, more in the upper lobe than the lower lobe, and cancer can occur from the main bronchus to the fine bronchus. Lung cancer originating from the main bronchus and lobe bronchi is called central lung cancer if it is located close to the hilum; lung cancer originating below the bronchi of the lung segment is called peripheral lung cancer if it is located in the peripheral part of the lung.
There are two basic types of lung cancer as follows.
1. small cell lung cancer (SCLC) or oat cell type, one third of lung cancer patients belong to this type.
2. the non-small cell lung cancer (NSCLC) category, to which two-thirds of lung cancer patients belong. This distinction is quite important because the treatment options for these two types of lung cancer are very different. Patients with small cell lung cancer are treated primarily with chemotherapy. Surgical treatment does not play a major role in patients with this type of lung cancer. On the other hand, surgical treatment is primarily indicated for patients with non-small cell lung cancer. Another type of cancer is pheochromocytoma.
II. Causes of lung cancer
The etiology of lung cancer is still not completely clear. A lot of information shows that the risk factors of lung cancer include smoking (including second-hand smoke), rock wool, radon, arsenic, ionizing radiation, halogenated alkenes, polycyclic aromatic compounds, nickel and so on. The details are as follows.
1.Smoking
Long-term smoking can lead to bronchial mucosa epithelial cell hyperplasia, phosphoepithelial growth and squamous epithelial carcinoma or undifferentiated small cell carcinoma.
2.Atmospheric pollution
3.Occupational factors
Long-term exposure to radioactive substances such as uranium and radium and their derivatives carcinogenic hydrocarbons arsenic chromium nickel copper tin iron coal tar asphalt petroleum asbestos mustard gas and other substances can induce lung cancer mainly squamous and undifferentiated small cell cancer.
4, chronic lung diseases such as tuberculosis, silicosis, pneumoconiosis, etc. can coexist with lung cancer and the incidence of cancer in these cases is higher than normal people. In addition, chronic inflammation of lung bronchus and lung fiber scar lesions may cause squamous epithelial metaplasia or hyperplasia during the healing process, on the basis of which some cases may develop into cancer.
5. Intrinsic factors such as family genetic inheritance and endocrine dysfunction with lowered immune function and metabolic activity, etc.
Lung cancer symptoms
(I) Early symptoms
Lung cancer does not have any special symptoms in early stage, but only symptoms common to general respiratory diseases, such as cough, sputum and blood, low fever, chest pain and tightness, which can be easily ignored.
The specific manifestations of common symptoms in early stage of lung cancer are
1. Cough. Since lung cancer grows on bronchopulmonary tissues, it usually produces irritating cough due to respiratory tract irritation.
2.Low fever. After the tumor blocks the bronchus, there is often an obstructive lobe of the lung, the degree of which varies from low fever in mild cases to high fever in severe cases, which may improve temporarily after medication but will recur soon.
3. Chest distension and pain. The chest pain in early stage of lung cancer is mild, mainly manifested as boring pain, hidden pain, the location is not certain, and the relationship with breathing is also uncertain. If the distending pain continues to occur, it indicates that the cancer may involve the pleura.
4. Sputum and blood. When tumor inflammation causes necrosis and capillary breakage, there will be a small amount of bleeding, which is often mixed with sputum and appears intermittently or intermittently. Many patients with lung cancer are diagnosed with sputum and blood.
(2) Late stage symptoms of lung cancer
1. Facial and neck edema. There is superior vena cava in the right side of mediastinum, which transmits venous blood from upper limbs and head and neck back to heart. If the tumor invades the right side of the mediastinum and presses the superior vena cava, the jugular vein will initially become angry due to poor return flow, and finally it will lead to facial and neck edema, which needs to be diagnosed and treated in time.
2. Hoarseness is the most common symptom. The laryngeal nerve, which controls the left side of the articulatory function, travels down from the neck to the chest and returns up to the larynx around the large blood vessels of the heart, thus innervating the left side of the articulatory organ.
3.Shortness of breath Almost all patients with regional spread of lung cancer have different degrees of shortness of breath. Normal tissue fluid produced by the lungs and heart muscle is returned by the lymph nodes in the middle of the chest. If these lymph nodes are blocked by the tumor, this tissue fluid will accumulate in the pericardium to form a pericardial effusion or in the thoracic cavity to form a pleural effusion. Both of these conditions can lead to shortness of breath. However, the combination of chronic lung disease of varying degrees in many smoking patients makes the identification of shortness of breath difficult. In addition, the loss of respiratory function due to tumor growth in some lung tissues may cause respiratory discomfort due to impaired proper respiratory function, which is initially felt only during exercise and eventually even at rest.
(3) Symptoms of widespread metastatic lung cancer: Because lung cancer is very prone to distant metastasis at an early stage, symptoms related to distant metastasis are often the first symptoms discovered by doctors or patients. If the lesion metastasizes to the brain, it may produce persistent headache and hazy vision. Continued progression may lead to confusion or even epilepsy.
If the cancer metastasizes to bone, it can lead to bone destruction, and when the destruction reaches a certain level, bone pain develops.
Finally, and most problematic, lung cancer has metastasized to the spine. In most patients, the occurrence of spinal metastasis can cause pain. The problem, however, is that the cancer can metastasize further into the spinal cord. This will first manifest as back pain and then spread to the lower extremities, where there may be weakness in the lower extremities, incontinence, and eventually paralysis below the point of metastasis. Therefore, the presence of back pain in heavy smokers should also be taken seriously.
However, the most common symptoms of distant metastases or systemic metastases are weakness and wasting. Patients with distant metastases all have unexplained wasting, which often occurs before the loss of appetite, and even if the appetite is increased, it does not help.
Diagnosis of lung cancer
The histopathological or cytological diagnosis of lung cancer can be made by sputum cytology, pleural fluid cytology, bronchoscopic pathology and cytology, or even fine needle aspiration or sectioning of lymph nodes.
For staging, enhanced CT of the chest, CT or ultrasound of the abdomen, CT of the brain, whole-body bone scan, pleural fluid cytology, thoracoscopic tissue biopsy, mediastinoscopic lymph node biopsy and PET-CT can be used.
V. Treatment methods of lung cancer
(I) Surgical treatment of lung cancer
Among the treatment methods of lung cancer, except for stage IIIb and IV, surgery or surgery should be the main treatment, and radiation therapy, chemotherapy and immunotherapy should be added according to different stages and pathological tissue types. As for small cell lung cancer, due to its high malignancy and early metastasis, chemotherapy should be the main treatment, supplemented by traditional Chinese medicine.
Regarding the survival period of lung cancer after surgery, it is reported in China that the survival rate of three years is about 40% to 60%; the survival rate of five years is about 22% to 44%; the mortality rate of surgery is less than 3%.
Surgical indications: Surgical treatment is generally available for those with the following conditions.
1.No distant metastasis, including parenchymal organs such as liver, brain, adrenal glands, bones, extra-thoracic lymph nodes, etc.
2. Cancerous tissues that have not spread to adjacent organs or tissues in the chest, such as the aorta, superior vena cava, esophagus and cancerous pleural fluid, etc.
3.No severe cardiopulmonary depression or recent angina attack.
4. Those without severe liver or kidney disorders and severe diabetes mellitus.
Those with the following conditions should generally be operated with caution or require further examination and treatment.
(1) Aging with poor cardiopulmonary function.
(2) Small cell lung cancer, except for stage I, should be treated with chemotherapy or radiotherapy before surgery is determined.
(3) Those who have several suspicious metastases in the mediastinum in addition to the primary foci as seen on x-ray.
At present, the indications for surgical treatment of lung cancer have been relaxed in academic circles. For patients with invasion of large intra-thoracic blood vessels and distant isolated metastases, some scholars think that they can be operated as long as their physical conditions permit, and relevant exploration and research have been conducted.
(B) Indications for dissecting thoracotomy
If the lesion is found to be beyond the resectable scope but the primary cancer can still be resected, it is appropriate to remove the primary focus, which is called reduction surgery, but in principle, total lung resection is not performed so as to assist other treatments after surgery.
(C) Selection of lung cancer surgery style
1.Local resection: it refers to wedge-shaped resection and lung segment resection, i.e., local resection can be considered for very small primary cancers with poor lung function in old age or low malignancy of well differentiated cancers.
2.Lobectomy: For isolated peripheral lung cancer, lobectomy is feasible for lung cancer that is confined to one lobe without obvious lymph node enlargement. If the cancer involves two lobes or the middle bronchus, upper middle lobe or lower middle lobe lobectomy is feasible.
3.Sleeve lobectomy: This procedure is mostly used for lung cancer in the upper and middle lobes of the right lung. If the cancer is located in the lobar bronchi and involves the opening of the lobar bronchi, sleeve lobectomy is feasible.
4. total pneumonectomy: total pneumonectomy can be carefully considered when the lesion cannot be removed with the above methods.
5.Lung resection and reconstruction: If the lung tumor exceeds the main bronchus and involves the ridge or the lateral wall of the trachea but does not exceed 2 cm: ①Lung resection and reconstruction or sleeve total pneumonectomy can be performed; ②If a lobe of the lung is still preserved, then strive to preserve it. The operation style can be determined according to the prevailing situation.
(D) Surgical treatment of recurrent lung cancer or recurrence
1.Surgery can certainly remove the cancer, but there are still residual cancer, or regional lymph node metastasis, or the presence of cancer thrombus in blood vessels, etc. The chance of recurrence and metastasis is very high. Long-term treatment after surgery by using Chinese herbal medicine true love san can prevent recurrence and transfer. Treatment of metastatic multiple primary lung cancer: the principle of treatment for anyone diagnosed as multiple primary lung cancer is treated according to the second primary focus.
2.The treatment of recurrent lung cancer: the so-called recurrent lung cancer refers to the cancer foci occurring within the original surgical scar or the recurrence of intra-thoracic cancer foci related to the primary foci, which is called recurrent lung cancer. The management principle should be based on the patient’s cardiopulmonary function and whether it can be resected to determine the scope of surgery.
(E) Chemotherapy of lung cancer
For inoperable patients and postoperative pathologically confirmed non-stage Ia patients, tumor chemotherapy is generally recommended. Currently, chemotherapy regimens for non-small cell lung cancer are divided into first-line chemotherapy regimens, second-line chemotherapy regimens and targeted therapy for lung cancer. In recent years, targeted therapy for lung cancer has been increasingly included in people’s view for patients who have relapsed after chemotherapy and whose first- or second-line chemotherapy is not effective, providing a new treatment direction to prolong patients’ survival. However, patients and their families still face certain difficulties in accepting them due to the disadvantages of being expensive and difficult for general families to afford.