Bar graph showing stage 3 lung cancer life expectancy for all stages of lung cancer, showing both 2-year and 5-year survival rates

What Is Stage III (3) Lung Cancer?

Most lung cancers are diagnosed with stage III (3) lung cancer. In stage 1 and stage 2, most symptoms are unnoticeable or mistaken for other illnesses. Early testing is integral to catching the disease when it’s most curable. Tumors at stage III can still be treatable, depending on several factors. These include the patient’s outlook and overall health, which will determine what treatment plan the doctor recommends and life expectancy.

Approximately 40 percent of lung cancer diagnoses are made in more advanced stages (such as stages 3 or 4). When lung cancer has approached the third stage, it’s moved from the lungs to other nearby tissues, organs, or lymph nodes. Common symptoms at this level include:

  • Bone pain
  • Chest discomfort
  • Difficulty breathing, shortness or loss of breath, wheezing
  • Excessive headaches
  • Scratchy or hoarse voice
  • Unexplained weight loss

If you experience any of the above symptoms, go to a doctor for an official diagnosis. They’ll take tests, assess your condition, and work with you on devising a plan on how to move forward.

Non-Small Cell Lung Cancer

Stage III for non-small cell lung cancer (NSCLC) is divided into three parts: IIIA, IIB, and IIIC. These levels are decided after the oncologist has evaluated the tumors, their size, and location.

This is an icon representing Stage IIIA in Lung Cancer Staging.

Stage IIIA

Tumors at this level are between three to five centimeters long and five to seven centimeters across in size. At this point, tumors have metastasized into the main bronchus and possibly other areas around the lungs, airways, and chest (pleura, pericardium, or lymph node), but they still remain on one side of the body.

This is an icon representing Stage IIIB in Lung Cancer Staging.

Stage IIIB

Cancer is five centimeters or longer and seven centimeters across. Tumors have made their way into the chest wall, the inner lining of the chest wall, the phrenic nerve, or pericardium. Possible spread to areas surrounding or between the lungs, aorta, or other blood vessels near the heart, trachea, esophagus, chest, backbone, or carina. Two or more lymph nodes may be affected.

This is an icon representing Stage IIIC in Lung Cancer Staging.

Stage IIIC

Tumors are greater than seven centimeters and have spread between the lungs, heart, blood vessels near the heart, windpipe, esophagus, diaphragm, spine, or carina. Two or more lymph nodes are affected in different lobes of the same lung or second lung.

Small Cell Lung Cancer

Stage 3 is labeled differently for small cell lung cancer (SCLC). SCLC’s subsections are known as limited and extensive depending on tumor location and size.

This is an icon representing Stage III - Extended in Lung Cancer Staging.

Stage III – Extended Stage

Stage III is considered extensive because tumors may have metastasized to the second lung, bone, brain, or bone marrow. Approximately two of every three people are diagnosed with extensive small-cell lung cancer.

Prognosis and Survival Rates

Prognosis refers to how your doctor believes the disease will continue to develop and how you may be affected by this development. This could mean what symptoms or side effects you may experience and their severity. Your doctor can also help you with resources and information to potentially improve your prognosis because it doesn’t always stay the same. It can differ with each patient and is based on general health and other factors.

A type of cancer’s survival rate is based on the percentage of people surviving five years after their official diagnosis. The survival rate for NSCLC stage IIIA is about 36 percent, 26 percent for stage IIIB, and one percent for stage IIIC. For extended-small cell lung cancer, the five-year survival rate is at about 16 percent. If tumors have spread to distant parts of the body, the survival rate is approximately three percent.

Keep in mind that each year’s survival rate data does not take into account new technologies and medicines that have been developed in the past five years.


Once your doctor makes a prognosis, they’ll develop a treatment plan. This may differ depending on if you have non-small cell lung cancer or small cell lung cancer.

Treating NSCLC

The stage III treatment plan your doctor produces will depend on the sub-stage non-small cell lung cancer is in, as tumors spread to different places.

Stage IIIA

Generally, treatment options at this level can include a combination of chemotherapy, radiation, and maybe surgery. Your plan’s exact details will vary based on the size of the tumor and its location in the lung, lymph nodes, or other areas. If a patient’s overall health is good, chemotherapy (sometimes combined with radiation) is the first method administered to patients. Surgery may come next to work on removing the remaining tumors.

Stage IIIB and IIIC

Tumors have metastasized to several lymph nodes near the second lung, the neck, or the collarbone. The chest may also be affected. The oncologist may recommend pairings of chemotherapy and radiation (sometimes referred to as chemoradiation) because tumors in the chest are hard to reach with surgery. If a patient cannot tolerate both treatments, the oncologist will use only one method at a time or a lower dose of both.

Doctors may recommend immunotherapies if the patient cannot handle primary methods.

Treating SCLC

At stage III, tumors have spread further into the body – SCLC may be classified as extensive-stage small cell lung cancer. Doctors may advise a combination of surgery, chemotherapy, and radiation to help fight tumors or manage pain.

Talk to Someone About Stage III Lung Cancer

Developed lung cancer because you were exposed to a carcinogen in the workplace? You may be able to take legal action against the companies responsible. Talk with an attorney about the details of your potential legal claim. You could use the money to pay for treatment or support your family.