Stage I (Early-Stage) Lung Cancer

Medically Reviewed by Jennifer Robinson, MD on November 16, 2021

Stage I lung cancer is the second-earliest stage of the disease. It means the abnormal cells in your airways have turned into cancer. But the tumor is only in your lung and hasn’t spread to your lymph nodes.

Stage I is also called early-stage lung cancer. It often can be cured, and most people can expect to live 5 years or longer.

Almost 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. The numbered stages are used more often with NSCLC.

Your doctor will figure out the stage of your cancer using 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 divide stage I non-small-cell lung cancer into two main subtypes. That helps them tell how serious your cancer is and decide on the best treatment.

Stage IA. Your tumor is only inside your lung and is not larger than 3 centimeters. That’s about the size of a walnut. This stage is broken down even further based on the size of the tumor:

  • Stage IA1: 1 centimeter or smaller, or not very invasive
  • Stage IA2: Larger than 1 centimeter but not larger than 2 centimeters
  • Stage IA3: Larger than 2 centimeters but not larger than 3 centimeters

Stage IB. Your cancer hasn’t spread to your lymph nodes. Stage IB is measured in one of two ways. The first is if your tumor is larger than 3 centimeters but not more than 4 centimeters.

Or your main tumor can be any size up to 4 centimeters, and at least one of the following is true:

  • Your tumor is in your main airway (the bronchus) but not within 2 cm ofwhere your windpipe splits to the left and right (the carina).
  • Your cancer has spread to the membrane covering the surface of your lung.
  • Your lung has collapsed or is inflamed (pneumonitis).

You may have early-stage lung cancer and not know it. Or you may notice some common signs, including:

It’s important to see your doctor about any symptoms. Your chances of beating lung cancer are directly tied to how early you catch it.

Sometimes stage I lung cancer is discovered through routine tests. Or your doctor may have reasons to think you have it. If so, you may get such tests as:

X-rays and imaging scans. X-rays may show a suspicious mass in your lung. Computed tomography (CT) scans can detect smaller tumors.

Your doctor may order 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 if it’s cancer.

With early intervention, stage I lung cancer can be highly curable. Usually, your doctor will want to remove the cancer with surgery. You also may need chemo or radiation therapy if traces of cancer remain or are likely to stay.

Radiation therapy is an option if you can’t have or don’t want surgery.

More men and women in the U.S. die of lung cancer than of any other type of cancer. But your odds of surviving stage I lung cancer are good. And your chances are generally better the lower your stage is at the time of your diagnosis.

For instance, about 92% of people with stage IA1 live for at least 5 years. That compares to 83% for those with stage IA2. The 5-year survival rate with stage IB -- the far end of stage I -- is 68%.

Finding out that you have even an early-stage cancer may leave you feeling shaken. Staying strong mentally and physically will help you through your treatments. Try and:

Educate yourself. Ask your doctor questions about your disease. Understand your treatment choices and what to expect from them. Knowledge will give you the confidence that you’re getting the best care for your cancer.

Seek support. Reach out to friends and family for emotional, practical, and other types of help. Or talk to a mental health therapist, a medical social worker, someone from your faith institution, or other trained professionals.

Connect with others. People who have cancer may understand what you’re going through in a way that’s harder for others. Join a cancer support group, either in person or online. The American Cancer Society has a searchable directory of groups and programs in your area. You can look up free or reduced-fee transportation, wigs, and other support.

Show Sources


National Cancer Institute: “NCI Dictionary of Cancer Terms.”

Suresh, S. Ramalingam, MD, deputy director, Winship Cancer Institute, Emory University.

American Cancer Society: “Non-Small Cell Lung Cancer,” “Non-Small Cell Lung Cancer Survival Rates,” “Cancer Staging,” “What Is Small Cell Lung Cancer?” “Non-Small Cell Lung Cancer Signs and Symptoms.”

National Health Service (UK): “Diagnosis: Lung Cancer.”

Mayo Clinic: “Lung Cancer Diagnosis,” “Lung Cancer.”

Methods in Molecular Biology: “Epidemiology of Lung Cancer Prognosis: Quantity and Quality of Life.”

Cedars-Sinai: “Lung Cancer.”

UpToDate: “Screening for lung cancer,” “Overview of the initial evaluation, diagnosis, and staging of patients with suspected lung cancer.”

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