This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science at CTCA.
This page was updated on May 6, 2022.
Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, according to the American Society of Clinical Oncology (ASCO). It makes up 84 percent of lung cancers.
NSCLC occurs when cells in the lungs change and grow out of control. It starts in the epithelial cells, which are found in the inner linings of the lungs. As cancer cells grow, they form a tumor. The tumor may shed cancer cells that spread to other parts of the body via the bloodstream, leading to metastasis.
The three main types of NSCLC are based on the types of cells that form the tumor:
Factors that may increase the risk for lung cancer include:
Lung cancer symptoms vary from person to person. Early cancer that hasn’t spread beyond the lung doesn’t usually cause symptoms.
As the cancer grows and spreads, symptoms may occur, which include:
Sometimes the first sign of non-small cell lung cancer is a spot on a routine chest X-ray. As cancer grows and spreads through the lungs or to other areas of the body—such as the lymph nodes, bones, brain or liver—more symptoms may develop.
These may include:
Imaging studies typically mark the beginning of the lung diagnostic process. Blood tests aren’t used to diagnose lung cancer.
Important imaging tests include:
In people at high risk, yearly screenings with a low-dose CT scan may help detect the cancer before symptoms start. ASCO recommends yearly screenings for patients aged 55 to 74 who have smoked a pack of cigarettes every day for at least 30 years, even if they have quit in the past 15 years.
Although imaging studies may detect lung cancer, a biopsy is necessary for a final diagnosis. A biopsy, which involves removing lung cancer cells and examining them under a microscope, may be performed in several ways, including:
After a biopsy, patients may undergo additional tests to look for genetic mutations or proteins in the cancer cells. Tumors that have mutations may respond to a type of cancer therapy called targeted therapy, while tumors with certain proteins may respond to a type of therapy called immunotherapy.
The final step in diagnosis, before treatment, is staging. The stage of lung cancer indicates the size of a tumor and whether it has spread, helping to determine the appropriate treatment options.
Stages for NSCLC run from 0 through 4:
Your multidisciplinary team will work with you to develop a personalized plan to treat your lung cancer in a way that fits your individual needs and goals.
Treatment of NSCLC depends on the stage.
The most likely treatment options include:
The five-year survival rate for this type of lung cancer is 25 percent, according to the American Cancer Society. That increases to 63 percent for NSCLC cases where the cancer hadn’t spread outside the lung.
It’s important to remember that the five-year survival rate is only an estimate, not an exact prediction. Since experts measure survival every five years, the numbers may not reflect newer and better diagnosis and treatment options, many of which are the result of clinical trials of new drugs.