There are two main types of primary lung cancer: small cell and non-small cell. These behave and respond to treatment quite differently. About 1 in 5 lung cancers are small cell, the rest non-small cell.

• Small cell lung cancer is sometimes called 'oat-cell' carcinoma because its cells are a distinctive oat shape.

• Non-small cell lung cancer – there are three types:

1. Squamous cell carcinoma is the commonest type of non-small cell lung cancer. It develops in the cells which line the airways.

2. Adenocarcinoma develops from the cells which produce mucus in the lining of the airways.

3. Large cell carcinoma gets its name from the large, rounded cells that are seen when they are examined under the microscope.

• Mesothelioma - A less common type of cancer that can affect the covering of the lungs is called mesothelioma (see Mesothelioma Fact Sheet). It is a cancer of the membrane which covers the surface of the lungs and lines the inside of the chest. It often occurs in people who have been exposed to asbestos.

Mesothelioma Fact Sheet

• Mesothelioma is a rare form of cancer that involves the mesothelium, or cells that line an organ, usually the lungs, abdominal organs, and heart. The most common form of mesothelioma is pleural mesothelioma, where malignant tumors form on the pleura, the sac that lines the chest cavity and protects the lungs. Other forms of mesothelioma affect the peritoneum (abdominal cavity lining) and the pericardium (lining around the heart).

• Mesothelioma is usually caused by asbestos exposure. Asbestos is a fibrous mineral known to be carcinogenic. People who are exposed to asbestos fibers for just a short period of time (few weeks) or even to a small amount may be at risk. In particular, people working with asbestos and their family members or those who live with them develop mesothelioma.

• There is a long latency period between initial exposure to asbestos and the development of malignant tumors. On average, 35-40 years elapse before the onset of disease.

• The early symptoms of mesothelioma can resemble pneumonia, including shortness of breath, difficulty breathing, persistent cough, chest and abdominal pain. Often, there is fluid buildup between the pleura and chest cavity (called pleural effusions), which leads to dyspnea (shortness of breath) and sometimes pain. Some people may not have any symptoms.

• Treatment for mesothelioma can be surgery to remove the tumors, chemotherapy, radiation, or a combination of the three.