Lung Cancer - Non-Small Cell: Introduction

Approved by the Cancer.Net Editorial Board, 05/2020

ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Non-Small Cell Lung Cancer. Use the menu to see other pages. Think of that menu as a roadmap for this complete guide.

Lung cancer affects more than 200,000 Americans each year. Although cigarette smoking is the main cause, anyone can develop lung cancer. Lung cancer is always treatable, no matter the size, location, whether the cancer has spread, and how far it has spread.

Because lung cancer is associated with smoking, patients may feel that they won’t receive much support or help because they believe that others will think that their behavior caused the disease. The truth is that most smokers do not develop lung cancer, and not all people diagnosed with lung cancer smoke. Lung cancer is a disease that can affect anyone. In fact, most people who get lung cancer today have either stopped smoking years earlier or never smoked.

About the lungs

When a person inhales, the lungs absorb oxygen from the air and bring the oxygen into the bloodstream for delivery to the rest of the body. As the body’s cells use oxygen, they release carbon dioxide. The bloodstream carries carbon dioxide back to the lungs, and the carbon dioxide leaves the body when a person exhales.

The lungs contain many different types of cells. Most cells in the lung are epithelial cells. Epithelial cells line the airways and make mucus, which lubricates and protects the lung. The lung also contains nerve cells, hormone-producing cells, blood cells, and structural or supporting cells.

About non-small cell lung cancer

There are 2 main classifications of lung cancer: small cell lung cancer and non-small cell lung cancer (NSCLC). These 2 types are treated differently. This guide contains information about NSCLC. Learn more about small cell lung cancer in a different guide. This website also offers a separate guide on neuroendocrine tumors of the lung.

NSCLC begins when healthy cells in the lung change and grow out of control, forming a mass called a tumor, a lesion, or a nodule. A lung tumor can begin anywhere in the lung. A tumor can be cancerous or benign. Once a cancerous lung tumor grows, it may shed cancer cells. These cells can be carried away in blood or float away in the fluid, called lymph, that surrounds lung tissue. Lymph flows through tubes called lymphatic vessels that drain into collecting stations called lymph nodes.

Lymph nodes are the small, bean-shaped organs that help fight infection. They are located in the lungs, the center of the chest, and elsewhere in the body. The natural flow of lymph out of the lungs is toward the center of the chest, which explains why lung cancer often spreads there first. When a cancer cell moves into a lymph node or to a distant part of the body through the bloodstream, it is called metastasis.

Types of NSCLC

NSCLC begins in the epithelial cells. It is important for doctors to distinguish between lung cancer that begins in the squamous cells from lung cancer that begins in other cells. This information is used to determine treatment options.

Your doctor will determine which type of NSCLC you have based on the way the cancer looks under a microscope. The different types of NSCLC are:

  • Adenocarcinoma

  • Squamous cell carcinoma

  • Large cell carcinoma

  • NSCLC-NOS (not otherwise specified) or NSCLC undifferentiated

  • Normal lung tissue
    Normal lung tissue
  • Lung - adenocarcinoma
    Lung - adenocarcinoma
  • Lung - squamous cell carcinoma
    Lung - squamous cell carcinoma

Images used with permission from the College of American Pathologists.

Looking for More of an Introduction?

If you would like more of an introduction, explore these related items. Please note that these links will take you to other sections on Cancer.Net:

The next section in this guide is Statistics. It helps explain the number of people who are diagnosed with NSCLC and general survival rates. Use the menu to choose a different section to read in this guide.