Lung cancer is one of the most common and difficult malignancies, and is thus a major focus of research.
To understand lung cancer, it is important to understand the anatomy of the lungs. The lungs are two organs found in the chest and are responsible for oxygen and carbon dioxide exchange. Each lung consists of lobes. The left lung contains two lobes, and the right lung contains three lobes.
When you breathe in, air travels into your lungs through the trachea (windpipe). The trachea then splits into two tubes, called the bronchi. The bronchi continue to branch forming smaller bronchioles, and at the end of these bronchioles are small air sacs called alveoli. Each lung is surrounded by a thin membrane called the pleura, which covers the lung and lines the chest cavity.
Lung cancer arises due to the abnormal proliferation of cells caused by changes (mutations) in the DNA. These mutations change the natural growth and death cycles of the cell and cause unregulated cell division. These rapidly dividing cells cause tumors. Tumors can be classified as either benign or malignant. Malignant cells invade normal tissues and often interfere with normal tissue functioning. When malignant cells originate in the lungs, physicians diagnose lung cancer.
There are two main types of lung cancer:
- Non-small cell lung cancer (NSCLC)
- Small cell lung cancer (SCLC)
While both of these cancers originate in the lung, they are treated differently. Treatment also differs depending on the staging of the cancer, patient health, and patient preference.