What is Lung Cancer?
Lung cancer is a term used to describe a growth of abnormal cells inside the lung. These cells divide and grow at a much quicker rate than normal cells. The cancerous cells stick together to form a cluster and this abnormal cluster of cells is called a tumor.
If the cancer cells first started growing in the lungs, the tumor is called a primary lung tumor. However, if the lung cancer cells break off and travel through the blood vessels they may latch on to and start to grow in other parts of the body, like the bones. This new cancer growth is called a metastasis or secondary tumor.
There are two different types of lung cancer: non-small cell lung cancer (NSCLC), which accounts for 85% of the cases, and small cell lung cancer. Non-small cell lung cancer can further be classified by histology, or how the cells and tissue look under a microscope. The major subtypes of NSCLC are adenocarcinoma, squamous cell carcinoma and large cell carcinoma. Adenocarcinoma is the most common, representing about 40 percent, whereas squamous cell carcinoma represents about 30%.