The terms lung cancer, bronchial carcinoma and bronchogenic carcinoma describe any of several different types of cancer affecting lung tissue. The incidence of this type of cancer is steadily increasing, particularly in women, and it is the most common form of internal cancer.
Smoking causes 90% of all lung cancers, but this effect of smoking is usually delayed until the patient is 55 or older. Other causes of lung cancer include asbestos dust, irradiation and chrome dust.
There are several different types of lung cancer, depending on the cells within the lung that are affected. The common types are:-
- Squamous cell carcinoma is a relatively common form, in which symptoms usually occur early, but the cancer doubles in size every three months on average, and spreads early to lymph nodes.
- Oat cell (small cell) carcinomas are far more serious, double in size every month on average, spread rapidly to other parts of the body, and are almost impossible to cure.
- Adenocarcinomas and large cell carcinomas develop at the edge of the lung, have few symptoms, are not easily detected, double in size every three to six months, but spread early to distant parts of the body.
- Secondary cancers are the spread of cancer from other parts of the body to the lungs. These are common, but they are not caused by smoking, and their treatment involves the treatment of the original cancer as well as that in the lung.
Many other rarer types of lung cancer are known.