Lung cancer is a disease characterized by new cell growth in lung tissue. If not treated, these cells can spread out of the lungs through a process called metastasis to the nearest tissue or another part of the body. Most cancers that start in the lungs, known as primary lung cancer, are carcinomas originating from epithelial cells. The main types of lung cancer are SCLC (small cell lung cancer), also called wheat cell cancer, and NSCLC (non-small cell lung cancer). The most common symptoms are cough (including coughing up blood), weight loss and shortness of breath

The most common cause of lung cancer is long-term exposure to tobacco smoke, which causes 80-90% of lung cancer. Non-smokers make up 10-15% of lung cancer cases and this case is usually caused by a combination of genetic factors such as radon gas, asbestos and air pollution including passive cigarette smoke. Lung cancer can be seen through chest x-ray and computed tomography (CT scan).

Signs and symptoms that indicate lung cancer, among others:

  • respiratory symptoms: such as coughing, coughing up blood, wheezing or shortness of breath
  • systemic symptoms: weight loss, fever, clubbing on the fingernails, or fatigue
  • these symptoms are caused by pressure in the local area: chest pain, bone pain, superior vena cava obstruction, difficulty swallowing

When cancer grows around the airway, it can cause shortness of breath. These obstacles can cause pneumonia.

Most lung cancer symptoms (loss of appetite, weight loss, fever, fatigue) are nonspecific In most people, cancer has spread from its initial location when symptoms occur and come to the doctor. The general location of its spread includes the brain, bones, adrenal glands, adjacent lungs, liver, pericardium, and kidneys. About 10% of people with lung cancer have no symptoms at the time of diagnosis; This cancer was discovered accidentally on chest X-ray examination


The graph shows how the increase in sales of tobacco products in the US in the first four decades of the 20th century (cigarettes per person per year) led to a rapid increase in lung cancer sufferers during the 1930s, 40s and 50s (lung cancer deaths per 100,000 population male per year) cross-section of the human lung: The white area in the upper lobe is cancer; black areas are colour changes that occur due to smoking.


Smoking, especially cigarettes, is generally a major contributor to lung cancer. Cigarette cigarettes contain more than 60 types of carcinogens, including radioisotopes from the decay of the radon, nitrosamine, and benzopyrene sequences. In addition, nicotine suppresses the immune response to cancerous growth in exposed tissue. In all developed countries, 90% of deaths from lung cancer in men during 2000 were caused by smoking (70% for women) Smoking is responsible for 80-90% of lung cancer cases.

Passive smoking – the process of inhalation of smoke from other smokers – is a cause of lung cancer in nonsmokers. Passive smokers can be classified as someone who lives or works with smokers. Research from the US Europe, the UK, and Australia have consistently shown a significant increase in risk among those exposed to passive cigarette smoke. Those who live with smokers have a higher risk of 20-30% while those who work in smokers’ environments have a 16–19% higher risk. Side flow smoke research shows that this is more dangerous than direct smoking Passive smoking causes 3, 400 lung cancer every year in the US.

Radon Gas

Radon is a colourless and odourless gas produced from the radioactive decomposition of radium, which is a product of uranium decay, in the layers of the earth’s crust. Radiation decay products ionize genetic material, and cause mutations that sometimes becomee cancerous. Radon is the second most common cause of lung cancer in the US, after smoking The risk increases to 8-16% for each increase in radon concentration of 100 Bq / m³


Asbestos can cause various lung diseases, including lung cancer. Smoking, tobacco and also asbestos have a synergistic effect on the formation of lung cancer Asbestos  also cause cancer of the pleura, called mesothelioma (which is different from lung cancer)

Air pollution

Air pollution outside the home only has a small effect in increasing the risk of fine particulate lung cancer (PM2.5) and aerosol sulfate, which originates from the release of motor vehicle fumes on the road, is associated with slightly increased risk. For nitrogen dioxide, the increase lasts to 10 parts per billion increases the risk of lung cancer by 14%. Outside air pollution is estimated to be responsible for 1-2% of lung cancer events.


It is estimated that 8 to 14% of lung cancer is caused by inherited factors. In people with relatives who have lung c ancer, the risk increases up to 2.4 times. This is caused by a combination of genes.

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