The lungs are divided into lobes and segments. The right lung has three lobes (upper, middle and lower) and the left lung has two lobes (upper and lower). Each lobe is further divided into segments.

Lung cancer originates in the tissues of the lungs, usually in the cells lining the air passages (bronchi).

Types of Lung Cancer:
The main types of lung cancer are:

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

NSCLC is said to account for approximately 80% of lung cancer cases and tends to grow slowly, whereas SCLC is less common, but more aggressive.