Cigarette smoking is the most common cause of lung cancer.
One common presenting symptom is a persistent cough.
Chest x-rays can detect most lung cancers, but other additional imaging tests and biopsies are needed.
Surgery, chemotherapy, targeted agents, and radiation therapy may all be used to treat lung cancer.
Lung cancer is the leading cause of cancer death in both men and women. It occurs most commonly between the ages of 45 and 70, and has become more prevalent in women in the last few decades because more women are smoking cigarettes.
Cancer that originates from lung cells is called a primary lung cancer. Primary lung cancer can start in the airways that branch off the trachea to supply the lungs (the bronchi) or in the small air sacs of the lung (the alveoli). Cancer may also spread (metastasize) to the lung from other parts of the body (most commonly from the breasts, colon, prostate, kidneys, thyroid gland, stomach, cervix, rectum, testes, bone, or skin).
There are two main categories of lung cancer.
Non–small cell lung carcinoma: About 85 to 87% of lung cancers are in this category. This cancer grows more slowly than small cell lung carcinoma. Nevertheless, by the time about 40% of people are diagnosed, the cancer has spread to other parts of the body outside of the chest. The most common types of non–small cell lung carcinoma are squamous cell carcinoma, adenocarcinoma, and large cell carcinoma.
Small cell lung carcinoma: Also called oat cell carcinoma, this cancer accounts for about 13 to 15% of all lung cancers. It is very aggressive and spreads quickly. By the time that most people are diagnosed, the cancer has metastasized to other parts of the body.
One common presenting symptom is a persistent cough.
Chest x-rays can detect most lung cancers, but other additional imaging tests and biopsies are needed.
Surgery, chemotherapy, targeted agents, and radiation therapy may all be used to treat lung cancer.
Lung cancer is the leading cause of cancer death in both men and women. It occurs most commonly between the ages of 45 and 70, and has become more prevalent in women in the last few decades because more women are smoking cigarettes.
Cancer that originates from lung cells is called a primary lung cancer. Primary lung cancer can start in the airways that branch off the trachea to supply the lungs (the bronchi) or in the small air sacs of the lung (the alveoli). Cancer may also spread (metastasize) to the lung from other parts of the body (most commonly from the breasts, colon, prostate, kidneys, thyroid gland, stomach, cervix, rectum, testes, bone, or skin).
There are two main categories of lung cancer.
Non–small cell lung carcinoma: About 85 to 87% of lung cancers are in this category. This cancer grows more slowly than small cell lung carcinoma. Nevertheless, by the time about 40% of people are diagnosed, the cancer has spread to other parts of the body outside of the chest. The most common types of non–small cell lung carcinoma are squamous cell carcinoma, adenocarcinoma, and large cell carcinoma.
Small cell lung carcinoma: Also called oat cell carcinoma, this cancer accounts for about 13 to 15% of all lung cancers. It is very aggressive and spreads quickly. By the time that most people are diagnosed, the cancer has metastasized to other parts of the body.
Causes
Cigarette smoking is the leading cause of cancer, accounting for about 85% of all lung cancer cases. About 10% of all smokers (former or current) eventually develop lung cancer, and both the number of cigarettes smoked and number of years of smoking seem to correlate with the increased risk. In people who quit smoking, the risk of developing lung cancer decreases, but former smokers will still always have a higher risk of developing lung cancer than people who never smoked.
About 15% of people who develop lung cancer have never smoked. In these people, the reason why they develop lung cancer is unknown. Recent studies have found that some people with lung cancer who have never smoked have genetic mutations in the epidermal growth factor receptor (EGFR) gene. Although an environmental association has not clearly been established, it is believed that exposure to radon gas in the home may be a risk factor. Other possible risk factors include exposure to secondhand smoke and exposure to carcinogens such as asbestos, radiation, arsenic, chromates, nickel, chloromethyl ethers, mustard gas, or coke-oven emissions, encountered or breathed in at work. It is believed that the risk of contracting lung cancer is greater in people who are exposed to these substances and who also smoke cigarettes. Air pollution and cigar smoke also contain carcinogens, and exposure to these substances is associated with an increased risk of cancer. In rare incidences, lung cancers, especially adenocarcinoma and bronchioloalveolar cell carcinoma (a type of adenocarcinoma), develop in people whose lungs have been scarred by other lung disorders, such as tuberculosis.