Lung cancer occurs in the mucosal epithelium of the bronchus and is also known as bronchopulmonary cancer. Lung cancer generally refers to cancer of the parenchyma of the lung and usually does not include other tumors of pleural origin, or other lung malignancies such as carcinoid tumors, malignant lymphomas, or tumors that have metastasized from other sources. Lung cancer accounts for 90-95% of all malignancies of the lung parenchyma. According to the World Health Organization, lung cancer is currently the number one cause of cancer deaths worldwide, accounting for approximately 19% of all malignancies. There are more than 1.2 million new cases worldwide each year. It has become the leading cause of death among men and the second leading cause of death among women after breast cancer. The current mortality rate of lung cancer in China is 40.57 per 100,000. In Tianjin, the incidence rate for men and women is 63.51/100,000 and 46.4/100,000, respectively.
The incidence rates in Shanghai were 47.13 per 100,000 men and 16.85 per 100,000 women. In urban areas, one out of every four deaths was due to cancer. And among every 3 to 4 deaths due to cancer, 1 is lung cancer. By 2025, China will have more than 1 million new lung cancer cases each year, making it the world’s number one lung cancer country. The disease mostly develops above the age of 40, with the peak age of incidence between 55 and 65.
The exact cause of lung cancer is still not known.
After many years of research and studies, the following factors are recognized to be closely related to the etiology of lung cancer.
(i) Smoking.
According to a large number of investigation data from various countries, the cause of lung cancer is extremely closely related to paper cigarette smoking. The increase in the incidence of lung cancer has a parallel relationship with the increase in the sale of paper cigarettes. Paper cigarettes contain many carcinogenic substances such as benzo(a)pyrene, which is one of the causative factors of lung cancer. Among the lung cancer deaths worldwide each year, 85% are caused by smoking. In addition, long-term inhalation of kitchen fumes is also an important factor leading to lung cancer. According to the data, among non-smoking female lung cancer patients in China, more than 60% are exposed to kitchen fumes for years, causing the eyes and respiratory tract to be stimulated by fumes, which is mainly caused by the fumes produced during frying. Fumes cause cancer mainly because cooking oil mutates under high temperature, and some of its own components will release carcinogenic substances such as acrolein under high temperature, and the higher the temperature, the more harmful substances will be produced.
(ii) Air pollution.
The high incidence of lung cancer in industrially developed countries, urban than rural areas, factories and mines than residential areas, is mainly due to the developed industrial and transportation areas, the burning of oil, coal and internal combustion engines, etc. and asphalt highway dust generated by containing benzopyrene carcinogenic hydrocarbons and other harmful substances pollution of the atmosphere. The survey material shows that the incidence of lung cancer increases in areas with high concentration of benzo(a)pyrene in the atmosphere. Atmospheric pollution and paper smoking may promote each other and play a synergistic role on the incidence of lung cancer.
(iii) Occupational factors.
The high incidence of lung cancer in the Schneeberg mines in Europe was reported in the literature in the 1930s of this century. After years of investigation and research, it is now recognized that long-term exposure to radioactive substances such as uranium, radium and their derivatives, carcinogenic hydrocarbons, arsenic, chromium, nickel, copper, tin, iron, coal tar, asphalt, petroleum, asbestos and mustard gas can induce lung cancer, mainly squamous carcinoma and undifferentiated small cell carcinoma, which is one of the predisposing causes of lung cancer.
(iv) Chronic diseases of the lung.
Such as tuberculosis , silicosis, pneumoconiosis, etc. can coexist with lung cancer. The incidence of cancer in these cases is higher than that in normal people. In addition, chronic inflammation of lung bronchus and lung fibers, scar lesions, may cause squamous epithelial chemosis or hyperplasia during the healing process, on the basis of which, some cases may develop into cancer.
(E) Intrinsic human factors.
Such as family inheritance, as well as lowered immune function, metabolic activity and endocrine dysfunction may also play a role in promoting the development of lung cancer.
Lung cancer is not contagious. Cancer cells need a specific environment in the human body to grow and multiply, and will die rapidly when they leave this environment and are expelled from the body. The cancer cell lines used in scientific research are cultured to live only under a variety of specific nutrients and conditions.
High-risk groups and prevention.
There are several known risk factors for the development of lung cancer, such as smoking, environmental pollution, occupational exposure, chronic diseases of the lungs and the body’s own immune system, and individuals with risk factors have an increased probability of developing lung cancer. Accordingly, prevention of lung cancer requires reducing exposure to risk factors, such as quitting smoking and using protective masks when working in exposed environments such as asbestos. Quitting smoking is the most effective way to prevent the occurrence of lung cancer.
Lung cancer symptoms.
The most common symptoms of early lung cancer are.
1. Cough, mostly irritating dry cough without sputum or a small amount of white mucous sputum, especially for heavy long-term smokers over 40 years old who have irritating dry cough without obvious causes for 2-3 weeks and the treatment is ineffective, or those who have chronic respiratory diseases and the nature of cough has changed should be alerted;
2. hemoptysis, mostly bloody sputum or blood in sputum.
3. Early stage of lung cancer often has mild chest tightness, and if it involves the wall pleura or directly invades the chest wall, it can cause persistent pain in that area. It should be emphasized that there are no specific symptoms in early stage of lung cancer. Any respiratory symptoms that do not heal after more than 2 weeks of treatment or any aggravation of the original symptoms should be alerted to the possibility of the existence of lung cancer.
Common symptoms of late stage lung cancer include.
1. Chest pain, most lung cancer patients who have undergone intra-thoracic regional dissemination have symptoms of chest pain.
2, dyspnea and shortness of breath. When tumor compresses large airways or produces large amount of pleural effusion, dyspnea occurs.
3.Face and neck edema. If the tumor invades the right side of mediastinum and presses the superior vena cava, the superior vena cava reflux will be blocked, causing bruising and varicose veins in the face and neck and upper limb anterior chest.
4.Heartness of voice. Tumor directly invades the recurrent laryngeal nerve or metastasizes to mediastinal lymph nodes, thus compressing the recurrent laryngeal nerve, which may lead to hoarseness of voice.
5.Weight loss, wasting is one of the most common symptoms of advanced malignant tumor. In advanced stage patients, due to tumor toxin and consumption, combined with infection and pain, appetite loss can cause wasting or cachexia.
6. Symptoms caused by distant metastasis of lung cancer, such as bone metastatic pain, brain metastasis causing headache, dizziness, weakness of one limb, etc.
Organs and parts most likely to be metastasized by late-stage lung cancer.
The most common metastatic sites of lung cancer are: brain, bone, adrenal gland, contralateral lung and liver.
Symptoms of lung cancer bone metastasis.
The most common symptoms of bone metastasis are local pain; bone destruction can occur after mild external force or spontaneous fracture; vertebral bone destruction or fracture may compress the spinal cord, which can cause limitation of movement or sensation of one or both limbs.
Symptoms of brain metastasis of lung cancer.
When brain metastasis occurs, it can produce the following symptoms: headache, vomiting, vertigo, diplopia, tinnitus and deafness, abnormal sense of smell, weakness or abnormal sensation of one limb, hemiplegia, unstable walking gait, mental symptoms, and in severe cases, it can cause intracranial hypertension, resulting in brain herniation and respiratory arrest, which can endanger life.
Symptoms of lymphatic metastasis of lung cancer.
If lung cancer metastasizes to hilar lymph nodes, it can compress the airway and cause pneumonia and shortness of breath; if it metastasizes to mediastinal lymph nodes, it can compress the recurrent laryngeal nerve and cause hoarseness, and compress the trachea and cause difficulty in breathing; if it metastasizes to supraclavicular or cervical lymph nodes, a hard, fused mass can be palpated under the skin of the neck, often without pain.
Lung cancer examination means.
After lung cancer is suspected through clinical symptoms and chest X-ray, patients need further examination to clarify the diagnosis and stage of lung cancer, firstly, qualitative examination, that is, to obtain pathological or cytological diagnosis, including sputum examination, bronchoscopy, mediastinoscopy, puncture biopsy, pleural fluid drainage cytology, open chest biopsy and exploratory surgery, etc., to clarify the diagnosis of lung cancer by obtaining tumor tissues or cells for pathological analysis; secondly, localization and Staging examination, mainly through CT scan, MRI, PET-CT, and bone scan imaging, can clarify the location of lung cancer and whether there is metastasis and the site of metastasis foci. Through the above pathological examination, staging examination, and the functional status of the patient’s organs, treatment strategies are formulated. In addition, blood tumor markers, such as CEA, NSE, CA125, etc. are also needed to help the diagnosis of lung cancer.
Common lung cancer laboratory tests.
For diagnosis: sputum cytology examination, pleural fluid cytology examination, and tumor histopathological tests such as bronchoscopy, mediastinoscopy, and puncture biopsy. For guiding clinical treatment: EGFR gene mutation detection, ALK translocation detection, etc. The examination of blood tumor markers is mainly used to assist diagnosis, treatment and follow-up: including CEA, CA125, NSE, SCC, Cyfra21-1, etc.
Lung cancer treatment.
The treatment of lung cancer is a comprehensive treatment mainly based on surgery. It includes radiotherapy, chemotherapy, biologic targeted therapy, immunotherapy, and Chinese herbal medicine treatment.
1.Surgery.
The purpose of surgery is to completely remove the lung tumor and the adjacent lymph nodes in the chest cavity. Lobectomy is the most effective surgical resection for non-small cell lung cancer, even if the tumor is very small. If lobectomy is not possible for whatever reason, the surgeon will wedge the tumor tissue and surround it with normal tissue cut edges as well. With central lung cancer, surgery may require a total lung resection. The recovery time after surgery depends on the size of the lung tissue removed and the patient’s preoperative health status.
2.Radiotherapy.
Radiotherapy is the application of high-energy X-rays or other energy particles to kill tumor cells. As with surgery, patients with extensive metastases are not suitable for radiation therapy. Radiotherapy can only kill the tumor cells in the path of the radiation beam, but it can also kill the normal tissue cells in that path. Therefore, radiotherapy cannot be applied if the radiation field involves too large an area of the body.
3.Chemotherapy.
Chemotherapy is the application of drugs to kill tumor cells. Systemic chemotherapy locates cancer cells through blood flow to the whole body. Chemotherapy is performed by medical oncologists. Research proves that chemotherapy can improve the quality of life and prolong the survival for most patients in most stages.
4.Targeted therapy.
It is a treatment that targets those defective genes and proteins that promote the development of cancer. In some lung cancer cells, these abnormal proteins are usually present in large quantities.
Bevacizumab (Avastin) is a drug that is used in combination with chemotherapy to treat lung cancer. Drugs in the bevacizumab class block the production of neovascularization, which is necessary for tumor growth and metastasis. The risk of serious bleeding with bevacizumab is 2 percent.
Cetuximab (Erbitux) is a drug similar to bevacizumab that blocks the epidermal growth factor receptor (EGFR), which promotes the growth and proliferation of cancer cells. Cetuximab may be considered in combination with chemotherapy for the treatment of lung cancer, especially when it is not safe to apply bevacizumab. Side effects of cetuximab include skin rash and allergic reactions.
Erlotinib (Troche) is approved by the U.S. Food and Drug Administration for locally advanced and metastatic non-small cell lung cancer. Gefitinib (ERSA) is a drug that works similarly to erlotinib. Exatinib (Kemena) is the 3rd EGFR small molecule targeted drug to enter the clinic. The new generation of targeted drugs such as afatinib are irreversible EGFR small molecule inhibitors that act on more sites.
For specific medication, please refer to the clinic and be guided by the doctor’s face-to-face consultation.
Treatment effect of early stage lung cancer.
Stage I and II non-small cell lung cancer generally require surgical treatment, and many patients can be cured by surgery, and the five-year survival rate can reach 45-65%, and some patients with early stage lung cancer have a survival period of more than 10 years, 20 years or long-term survival. adjuvant chemotherapy after surgery for some patients with risk factors in stage I and stage II patients can also further reduce the risk of recurrence. Small cell lung cancer in the limited stage has a cure rate of about 20%.
Treatment outcomes for intermediate to advanced lung cancer.
Most stage III non-small cell lung cancers cannot be cured by surgery or radiotherapy alone, but the current clinical use of multiple treatments, chemotherapy followed by surgery, or synchronous or sequential radiotherapy, can cure some patients. Most stage IV lung cancers are not curable and are usually treated with chemotherapy and targeted therapy only, which can improve the survival quality and prolong the survival period of stage IV patients. Patients in this stage have an overall median survival time of 8-10 months, a 1-year survival rate of 30-40%, and a 2-year survival rate of 10-15% if they receive chemotherapy alone. If patients have EGFR-sensitive mutations, approximately 50% of patients can achieve a survival time of approximately 3 years after treatment. The median survival time for extensive stage small cell lung cancer is 9-11 months, and the 2-year survival rate after treatment is also less than 5%.