Where does lung cancer start?

 Where does lung cancer start?

Lung cancer is a type of cancer that starts in the lungs. The lungs are a pair of spongy organs located in the chest that are responsible for taking in oxygen and removing carbon dioxide from the body. Lung cancer usually starts in the cells that line the air passages, such as the bronchi, bronchioles, or alveoli.

The majority of lung cancers (about 85%) are classified as non-small cell lung cancer (NSCLC), which includes three main subtypes:

1. Adenocarcinoma: This is the most common type of lung cancer, accounting for about 40% of cases. It typically starts in the cells that line the small air sacs (alveoli) in the outer parts of the lungs. Adenocarcinoma is more common in non-smokers and women.

2. Squamous cell carcinoma: This type of lung cancer starts in the cells that line the airways. It accounts for about 25-30% of all lung cancers and is strongly associated with smoking.

3. Large cell carcinoma: This is a less common type of lung cancer, accounting for about 10-15% of cases. It can start in any part of the lung and tends to grow and spread quickly.

The remaining 15% of lung cancers are classified as small cell lung cancer (SCLC). SCLC starts in the cells that line the bronchi and tends to grow and spread more quickly than NSCLC. It is strongly associated with smoking and accounts for about 10-15% of all lung cancers.

In some cases, lung cancer may start in other parts of the body and then spread to the lungs. This is known as metastatic lung cancer and is not considered a primary lung cancer.

It's important to note that early-stage lung cancer may not cause any symptoms, and it may be found incidentally during a routine chest X-ray or CT scan. That's why regular screening is recommended for people at high risk for lung cancer, such as those with a history of smoking or exposure to certain substances.