-Tobacco smoking: Smoking is the number one risk factor for lung cancer. (M)
-Secondhand smoke: Smoke from other people's cigarettes causes lung cancer in people and animals. (M)
-Radon: This naturally occurring gas comes from rocks and dirt and can get trapped in houses and buildings. It cannot be seen, tasted, or smelled. Radon causes about 20,000 cases of lung cancer each year, making it the second leading cause of lung cancer.
-Asbestos: People who work with asbestos are several times more likely to die of lung cancer. (M)
-Environmental exposure in some workplaces: Carcinogens include radioactive ores such as uranium; inhaled chemicals or minerals such as arsenic, beryllium, cadmium, silica, vinyl chloride, nickel compounds, chromium, coal products, mustard gas, chloromethyl ethers, and diesel exhaust. (M)
-Air pollution: In cities air pollution appears to raise the risk of lung cancer slightly. (M)
-Radiation therapy to the chest: Cancer survivors who had radiation therapy to the chest are at higher risk of lung cancer.
-Personal and family history: People who have lung cancer are at a higher risk of developing another lung cancer. Brothers, sisters, and children of people who have lung cancer have a slightly higher risk of lung cancer themselves. However, it is difficult to say how much of the excess risk is the result of genetic factors versus environmental tobacco smoke.
The signs vary, depending on the amount of lung collapse. If there is very minor collapse, the patient may be slightly short of breath, anxious, and report chest pain. If a large amount of lung collapses, the patient may experience severe respiratory distress, including tachycardia, dyspnea, tachypnea, and cyanosis. Breath sounds over the affected area are absent. Decreased chest wall movement on the affected side may be noted. The patient may also have paradoxical chest wall movement, when the chest wall moves in on inspiration and out on expiration. If severe, there may be tracheal displacement toward the unaffected side with a mediastinal shift, termed a tension pneumothorax