Stage III Non-Small Cell Lung Cancer: Symptoms, Diagnosis, and Treatment

According to the Centers for Disease Control¹, lung cancer is the third most common cancer type and the leading cause of cancer death in the United States. There are more than 200,000 new cases of lung cancer each year.

Lung cancer begins in the lungs, and it can progress quite quickly through the stages, roughly doubling in size every four or five months. In more advanced stages, it can spread to other parts of the body.

The American Cancer Society² reports that smoking is the primary cause of lung cancer, contributing to around 80% of lung cancer deaths. However, not everyone diagnosed with lung cancer uses tobacco products. Second-hand smoke, exposure to carcinogens, and air pollution can contribute to the development of lung cancer.

Have you considered clinical trials for Lung cancer?

We make it easy for you to participate in a clinical trial for Lung cancer, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

What is stage III non-small cell lung cancer?

Lung cancer starts in stage 0 when the tumor is small and non-invasive. It continues through stage IV, the most serious stage of the disease, where cancer has spread throughout the body.

According to a study in the Journal of Thoracic Disease³, around 40% of patients aren't diagnosed with lung cancer until the advanced stages. About a third of those newly diagnosed cases are in stage III. In these advanced stages of lung cancer, patients experience more serious symptoms.

In stage III, lung cancer has spread from the original site to other areas of the chest. However, cancer hasn't spread outside of the chest to other areas of the body. Stage III has three categories, determined by how far cancer has spread through the chest.

Stages IIIA, B, and C have treatment options, but the survival rate decreases as the cancer spread.

What are the symptoms of stage III lung cancer?

The earliest symptoms of lung cancer resemble the side effects experienced by many smokers: persistent coughing and shortness of breath. As the disease advances, symptoms become more serious, and many patients feel generally unwell.

By the time lung cancer reaches stage III, symptoms can also include:

  • Coughing that's suddenly worse, deeper, or doesn't go away

  • Unexplained weight loss

  • Wheezing or being short of breath even without physical exertion

  • Pain in the chest area

  • Extreme fatigue

  • Changes in the tone of voice

  • Coughing that produces blood or sputum

These symptoms are commonly mistaken for other health concerns, such as a bad cold or pneumonia. That's why it's vital to get checked by a doctor, especially if you are at a higher risk of developing lung cancer. If you are experiencing any of these symptoms, make an appointment with your healthcare professional. They can determine the underlying cause.

Screening for lung cancer is controversial, but patients aged 50 to 80 with a significant smoking history may benefit. Speak to your doctor if you have any questions. 

How is stage III lung cancer diagnosed?

Doctors use tests to determine whether you have lung cancer and what stage it's in. These diagnostic tests include:

CT and PET scans

Imaging tests let your doctor see inside your lungs. These tests can detect the presence of any tumors, appearing as spots or shadows on your lungs, but they may not be cancerous. To determine that, your doctor will need to do a biopsy.


If there is anything unusual on your imaging tests, your doctor might do a biopsy. This involves taking a small sample of an abnormal mass of cells to see if they are cancerous. Some lung biopsies may require surgery to reach the abnormal cells.

Your doctor may collect the sample by putting a camera down your throat while you are sedated. In other cases, they may collect the sample with a needle during an outpatient procedure.

Sputum cytology

Sputum is thick phlegm produced by some people with lung cancer when they cough. Your doctor can look at sputum under a microscope to check for signs of cancerous cells. 

What are the treatment options for stage III lung cancer?

Stage III lung cancer is treatable. Every patient, tumor, and case is different, so the treatment options will vary. Your oncologist (a doctor specializing in cancer) will work with you to determine the best course of action. Some treatment options for stage III lung cancer include:

  • Surgery: Your doctor may decide that removing cancerous tissue is the best option. You may need chemotherapy afterward. 

  • Chemotherapy: Cancer-killing medications are given to the patient through the veins via an infusion.

  • Radiation: This process involves aiming high-energy radiation at the cancerous tissue to kill it. 

  • Immunotherapy: If surgery is not feasible (with extensive lymph node involvement), then a combination of chemotherapy and radiotherapy followed by immunotherapy is the current treatment for most stage III cancer patients.

In stage III, an oncologist might determine that one or a combination of all four treatments is the best option. They may also recommend a clinical trial with new medications or procedures. They'll help you manage any treatment side effects and offer suggestions on how to stay comfortable during recovery.

Learn more about how lung cancer is treated.

What's the prognosis for stage III lung cancer?

Although stage III non-small cell cancer is treatable, it can come back in a significant number of patients. Five-year survival rates vary between 40% for stage IIIA patients and around 10% for stage IIIC patients. Newer treatments such as immunotherapy have improved outcomes for stage III patients with non-small cell lung cancer.

The lowdown

Lung cancer is the third most common type of cancer in the United States. As with many cancers, it may not cause symptoms until more advanced stages. By stage III, lung cancer has grown in size and spread to nearby lymph nodes. Symptoms include persistent coughing, chest pains, and coughs that produce sputum or blood.

Doctors diagnose cancer through imaging tests and biopsies. On diagnosis, an oncologist may recommend surgery, radiation, chemotherapy, immunotherapy, or a combination of these treatments. Targeted therapy may be an option in patients with changes in cancer signaling genes.

It's important to remember medications and treatment protocols are improving all the time, and survival rates will depend on your case.

The earlier doctors diagnose lung cancer, the better the survival, so it’s important to get any symptoms checked.

Have you considered clinical trials for Lung cancer?

We make it easy for you to participate in a clinical trial for Lung cancer, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

Discover which clinical trials you are eligible for

Do you want to know if there are any Lung cancer clinical trials you might be eligible for?
Have you taken medication for Lung cancer?
Have you been diagnosed with Lung cancer?