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). 

Lung cancer chemotherapy treatments are used in three primary ways: 1.Neoadjuvant or primary systemic lung cancer chemotherapy may be used before surgery to destroy cancer cells. It also allows your oncologist to determine the effect of a particular lung cancer treatment regimen on the tumor. 2.Adjuvant chemotherapy is used after surgery or radiation to target cancer cells that were not removed during lung cancer surgery, and helps prevent the cancer from spreading to other parts of your body. 3.Systemic chemotherapy, meaning the circulation of chemotherapy drugs through the bloodstream to cancer cells through the body, plays an important role in the treatment of locally advanced or metastatic lung cancer.1