Stage III Lung Cancer

Medically Reviewed by Paul Boyce, MD on November 04, 2023
5 min read

Doctors use stages to describe how much cancer you have and where it is in your body. People with stage III lung cancer can be a very mixed group. Their tumors can differ in sizes, where they’re located, and how distant they are from where the cancer started.

But almost always, stage III cancer is in just one lung. It’s also limited to the lymph nodes, organs, and other tissue near that organ. The cancer has not spread, or metastasized, beyond that. That’s why this stage is also called locally advanced or locoregional disease.

The next stage, stage IV, is the last and most serious stage of cancer.

Nearly 9 out of 10 people with lung cancer have non-small cell-lung cancer (NSCLC). A rarer and more aggressive type is called small-cell lung cancer. But the numbered stages are used mainly with the more common NSCLC.

Staging uses three key criteria called TNM:

Tumor (T). How big and where is the tumor?

Nodes (N). Is the cancer in nearby lymph nodes?

Metastasis (M). How far has the cancer spread from its original spot?

Doctors split stage III non-small-cell lung cancer into three main subtypes. It helps them get a more detailed picture of your cancer and to decide on the best treatments.

Stage IIIA. You have one or more tumors in one lung. The cancer is in nearby lymph nodes. The cancer may be in certain nearby tissues, but it hasn’t reached distant organs.

Stage IIIB. You have one or more tumors in the same lung. Your cancer may have spread to lymph nodes above your collarbone and may be in lymph nodes on the opposite side of your chest. The cancer may be in certain nearby tissues but not in distant organs.

Stage IIIC. This is the most advanced stage within stage III. You have one or more tumors in the same lung. Your cancer has spread to lymph nodes above your collarbone or to lymph nodes on the opposite side of your chest. The cancer may be in the chest wall, heart, breastbone, and other nearby tissues but hasn’t spread to distant organs.

Most non-small-cell lung cancer is found after it’s become advanced. That’s partly because the disease worsens quickly and often doesn’t have signs in early stages. But symptoms may include:

If your stage III lung cancer has spread beyond your lungs, it can cause other symptoms. For example, you may have bone pain if it has spread to your bones.

Your doctor probably found your lung cancer after checking your symptoms. Most people aren’t routinely checked for the disease unless they smoke or otherwise face a higher risk.

A chest X-ray is often the first image test. If it suggests you have cancer, you’ll have follow-up tests, such as:

Computed tomography (CT). Your doctor may order a “contrast-enhanced” version of this scan, which can take more detailed images.

Your doctor may run other tests to check the extent of your cancer. They might include:

Biopsy. A doctor will examine a sample of your tissue under a microscope to confirm that it’s cancer.

Your doctors have several ways to treat you based on the size, location, and other characteristics of your cancer:

Surgery. If possible, your doctor may opt for an operation to remove all the tumors.

Chemotherapy. You often may get this after surgery to help suppress any future cancers.

Radiation. If surgery couldn’t take out all of the cancer, you may get radiation therapy. Or you may have chemotherapy followed by radiation therapy.

Chemoradiation. If surgery isn’t an option, you may get chemotherapy or radiation therapy, or both at the same time.

Immunotherapy. This uses drugs to rally your body’s own immune system to fight the cancer. Your doctor may use immunotherapy as a first treatment if surgery isn’t a good choice, or use it after chemoradiation.

More people in the U.S. die of lung cancer than of breast, colon, and prostate cancers combined. About 1 in 3 people diagnosed with stage IIIA lung cancer live for at least 5 years after their diagnosis. For stage IIIB, the average 5-year survival rate is 26%. For stage IIIC, it’s 13%.

Your long-term outlook may be better if you:

  • Have lost less than 5% of your weight before starting treatment
  • Are a woman
  • Do not have a lung infection, collapsed lung, or fluid buildup around the lung
  • Have a type of cancer cell that responds well to certain treatments

Any serious illness can bring worry, uncertainty, and other challenges to you and to your loved ones. Try to:

Manage your pain. You may hurt not just from your cancer but from treatments as well. Work with your doctors to control your pain as well as you can. That also may help lower your chances of depression.

Ease other symptoms. Weight loss is common when you have cancer. Eat well to help keep up your strength and to prevent infections. For constant coughs, you might find relief with:

Pulmonary rehab may also improve your symptoms and quality of life. It may help you breathe easier and to stay more active.

Quit smoking. It’s never too late to stop. People who give up smoking before their cancer treatments tend to respond better. If it’s hard for you to quit, a  smoking cessation program may help.

Connect with others. There is no such thing as too much support. It may help to talk to a medical social worker, mental health counselor, or other professionals. Join a cancer support group, either in person or online. Find out if any local groups offer free rides to appointments and other help. The American Cancer Society has a searchable directory of programs.