Lung Cancer Basics

Key Points

  • Lung cancer is a disease in which cells in the lungs grow out of control.
  • Lung cancers usually are grouped into two main types called small cell and non-small cell.
Photo of a man and a woman

What it is

Lung cancer begins in the lungs and may spread to lymph nodes or other organs in the body, such as the brain. Cancer from other organs also may spread to the lungs. When cancer cells spread from one organ to another, they are called metastases.

Illustration of the respiratory system showing the lungs, bronchi, trachea, larynx, pharynx, and nasal cavity
This illustration of the respiratory system shows the lungs, bronchi (tubes leading to the lungs), trachea (windpipe), larynx (voice box), pharynx (throat), and nasal cavity.

Types

Lung cancers usually are grouped into two main types called small cell and non-small cell (non-small cell includes adenocarcinoma and squamous cell carcinoma). These types of lung cancer grow differently and are treated differently. Non-small cell lung cancer is more common than small cell lung cancer.