Lung cancer is an uncontrolled growth of cells that start off in the lungs. Instead of developing into healthy lung tissue, the cells divide rapidly and forms malignant tumours. These malignant tumours develop in the cells of the lungs is known as lung cancer. Usually, lung cancer starts in the cells that line the air passages and it can also spread to other parts of the body.

There are two types of lung cancers based on cell size:-

• Small cell lung cancer (SCLC)
• Non-small cell lung cancer (NSCLC). 

As researchers have learned more about the changes in non-small cell lung cancer (NSCLC) cells that help them grow, they have developed newer drugs to specifically target these changes. Targeted drugs work differently from standard chemotherapy (chemo) drugs. They sometimes work when chemo drugs don’t, and they often have different (and less severe) side effects. At this time, they are most often used for advanced lung cancers, either along with chemo or by themselves.