What are the causes of small cell lung cancer

We all know that small cell lung cancer is closely related to smoking. However, among patients with small cell lung cancer, in addition to smokers, there are many non-smokers who also suffer from the disease. It is understood that most of them have been poisoned by secondhand smoke for a long time. The factors that lead to small cell lung cancer need our attention. So what are the main causes of small cell lung cancer? Let me introduce them to you below.

1. Smoking

The relative risk of death from lung cancer for smokers is 12.7. For those who smoke more than 30 cigarettes a day, the relative risk increases by 22.3 times compared with non-smokers. In 1985, 82% of lung cancer deaths or 31,600 deaths in the United States can be attributed to smoking. Many epidemiological studies have been conducted at home and abroad on the relationship between smokers and different types of lung cancer. Most of the research results show that smoking is closely related to squamous cell lung cancer and small cell lung cancer. At the same time, studies have shown that the risk of death from lung cancer can be reduced to the level of non-smokers after quitting smoking for 10-15 years.

2. Environmental tobacco smoke

It is composed of sidestream smoke released from burning tobacco and smoke exhaled by smokers, which account for 80% and 20% respectively. The smoke inhaled by smokers is called mainstream smoke. ETS contains various toxic substances, including mutagens and carcinogens, such as some chemicals (nitrous acid, 4-aminobiphenyl, benzopyrene), which are higher in ETS than in mainstream smoke released by burning tobacco. Studies have shown that the level of 4-aminobiphenyl-hemoglobin compounds in passive smokers is approximately equivalent to 14% of that in active smokers. 2%-3% of lung cancer diagnosed in smokers and non-smokers each year is caused by ETS.

3. Air pollution

It refers to the pollution formed after the pollutants are fully diluted by the air after being discharged. With the development of industry, especially the emission of waste gas and gas from cities and factories, the large-scale production and use of various carcinogenic industrial raw materials and products, the carcinogens in the air are increasing; various means of transportation, especially the exhaust gas discharged by cars, and the large-scale use of materials such as asphalt in paving and construction, cause air pollution.

Although lung cancer is mainly attributed to smoking in most countries, the risk for men who are already smokers and are exposed to urban air pollution is as high as 10 cases of lung cancer per 100,000 people per year. The results are therefore caused by the interaction of tobacco with chemical compounds in the atmosphere and vary by geographic region and over time.

4. Chronic lung diseases

For example, tuberculosis, silicosis, and pneumoconiosis can coexist with lung cancer. The incidence of these lung cancers is higher than that of normal people. In addition, chronic inflammation of the lung bronchus and lung fibrosis scar lesions may cause squamous metaplasia or hyperplasia during the healing process. On this basis, some lung cancer patients may develop into cancer.