About Lung Cancer
What is lung cancer?
Lung cancer is a disease of the lung cells. It means that cells in the lungs grow and divide abnormally.
The origin of lung cancer is in the cells of the lung. Other cancers that spread to the lung are not lung cancer, for example, a liver cancer that has spread to the lung is still a liver cancer.
What are the types of lung cancer?
There are two main types of lung cancer.
- Non-small-cell lung cancer (NSCLC): 85% of lung cancer cases. This type has the best prognosis.
- Small-cell lung cancer (SCLC): 15% of lung cancer cases.
It is important to know what type of lung cancer you have because treatments for each type are different.
Where can lung cancer be in the body?
The disease can be:
- Localised: When the cancer is only in the lungs in the form of a tumor, also known as the primary site.
- Regional: When the cancer has spread from the lungs to nearby lymph nodes, also known as tumour extension.
- Distant: When the cancer has spread to other organs in the body, also known as metastatic spread.
How can lung cancer affect you?
Lung cancer can cause a number of symptoms such as:
- Bigger lymph nodes (for example, on the neck)
- Shoulder and arm pain or chest pain (due to nerve involvement)
- Difficulty in speaking (due to paralysis of a vocal cord)
- Difficulty in swallowing (when the tumour compresses the oesophagus/food pipe)
If the cancer spreads to another part of the body, symptoms and signs may appear in the affected organs, for example, neurological or bone symptoms.
Sometimes a person without symptoms or signs can have a small clump of cells in the lung (lung nodule). Your medical team will decide how best to deal with this nodule to check if it is cancerous or not.
How do the lungs work?
The lungs are the main organs of the respiratory system. They exchange the gases that enter and leave the body. We breathe in oxygen and breathe out carbon dioxide. When oxygen enters the lungs, it passes into the blood, and goes to all cells in the body. Then, carbon dioxide is removed from all cells in the body.
1. Inhalation
When we inhale, the air passes through the throat to the windpipe (trachea).
2. Air Enters Lungs
Then, air enters the lungs through the bronchi. There are three levels of bronchi: main (primary), lobar (secondary), and segmental (tertiary).
3. Gases are exchanged
At the end of each bronchiole there are bunches of alveoli wrapped in blood vessels. This is where the exchange of gases in and out of the blood occurs.
4. Lungs Receive Air
Lobes are sections of the lung, and each one receives the air from a bronchus. The right lung has three lobes, and the left lung has two lobes.
The lungs are covered by a tissue called pleura. It has two layers: the outer layer is called parietal pleura and the inner layer is called visceral pleura. The space between them is called the pleural cavity, which is filled with a small amount of liquid called pleural fluid.
Throughout our body, including the lungs, there is a clear fluid called lymph. It gives cells food, water, and immune cells to fight germs. Lymph is distributed by lymph vessels, and it passes through small structures called lymph nodes. There are lymph nodes in the lung along the bronchi, and for example they are connected with others located near the trachea and on the neck.