What Is Non-Small Cell Lung Cancer?

What Is Non-Small Cell Lung Cancer?

Lung cancer begins when lung cells become abnormal and begin to grow out of control. As most cancer cells develop, they can form in a tumor and spread to other areas of the body. For more information on how to start and spread cancer, see what is cancer?

Types of non-small cell lung cancer

There are 2 main types of lung cancer:

Approximately 80% to 85% of lung cancers are non-small cell lung cancer (NSCLC)

Approximately 10% and 15% are small cell lung cancer (SCLC)

These types of lung cancer are treated very differently. This information refers only to non-small cell lung cancer cancer.

There are subtypes of NSCLC, which come from different types of lung cells. But they are grouped into NMSC because the approach to treatment and prognosis (perspective) are often similar.

Adenocarcinoma: About 40% of lung cancers are adenocarcinomas. These tumors begin in the early versions of cells that normally secrete substances such as mucus.

This type of lung cancer occurs mainly in smokers or ex, but it is also the most common type of lung cancer that is seen in non-smokers. And 'more common in women than in men, and is more likely to occur in people younger than other types of lung cancer.

Adenocarcinoma is usually found in the outer parts of the lungs. Although it tends to grow more slowly than other cancers to the lungs and is more likely to be found before it has spread, this varies from one patient to another.

People with a type called adenocarcinoma  (before named bronchio alveolar carcinoma) and have a better prognosis than those with other types of lung cancer.

Cellular (epidermoid) squamous cell carcinoma: About 25% to 30% of all lung cancers are squamous cell carcinomas. These tumors begin in the early versions of squamous cells, which are flat cells that line the inside of the airways of the lungs. They are often related to a history of smoking and tend to be found in the central part of the lungs, near a main airway (bronchi).

A large (undifferentiated) cell carcinoma: the amount of this type is approximately 10% to 15% of lung cancers. It can appear anywhere in the lung. It tends to grow and spread quickly, which can make it more difficult to treat. A large cell carcinoma subtype, known as large cell neuroendocrine carcinoma, is a rapidly growing tumor that is very similar to small cell lung cancer.

Other subtypes: Some other NSCLC subtypes, such as adeno-squamous carcinoma and sarcomatoid carcinoma, are much less common.

Other types of lung cancer

Along with the two main types of lung cancer, other types of cancer can occur in the lungs.

Carcinoid lung tumors: Carcinoid tumors of the lung account for less than 5% of lung cancers. Most of these grow slowly. For more information about these tumors, see lung carcinoid tumor.

Other types of lung cancer: Other types of lung cancer, such as cystic adenoid carcinomas, lymphomas and sarcomas, as well as benign tumors of the lung such as hamartomas are rare. These are treated differently from most common lung cancers and are not discussed here.

Cancers that spread to the lungs: Tumors that originate in other organs  can many times growing rapidly or metastasize to the lungs, rather these are not lung cancers. For example, cancer that begins in the breast and spreads to the lungs is still breast cancer, not lung cancer. Treatment for metastatic lung cancer refers to the starting point (the site of the primary cancer).

 function of the lungs

The lungs are two spongy organs in your chest. Your right lung has three sections, called lobes. Your left lung has two lobes. The left lung is smaller because the heart occupies more roomon than the side of the body.

When breathing, air enters through the mouth or nose and passes into the lungs through the trachea (trachea). The trachea is divided into tubes called bronchi (singular, bronchi), which enter the lungs and divide into smaller bronchi. These divide to form the smaller branches called bronchioles. At the end of the bronchioles are small air sacs known as alveoli.

The alveoli absorb oxygen from inhaled air into the blood and remove carbon dioxide from the blood. It is expelled from the body as it exhales. Taking oxygen and eliminating carbon dioxide is the main lung function.

Lung tumors usually begin in the cells that line the bronchial ducts and lung parts, such as the bronchioles and alveoli.


Illustration showing the details of the lungs and surrounding areas
A thin layer coating called the pleura surrounds the lungs. The pleura protects the lungs and helps them slide back and forth against the chest wall as they expand and contract during respiration.

Under the lungs, thin, dome-shaped muscle called the diaphragm separates the thorax from the abdomen. When breathing, the diaphragm moves up and down, forcing air in and out of the lungs