This page was reviewed under our medical and editorial policy by
Peter Baik, DO, Thoracic Surgeon
This page was reviewed on January 8, 2023.
A lung cancer diagnosis includes its stage, or how extensively the cancer has progressed. Lung cancer staging starts with three main factors, called TNM for short:
T (tumor): This refers to the size of the primary tumor.
N (nodes): This refers to the number of lymph nodes involved.
M (metastasis): This indicates whether the cancer has spread (metastasized) to other areas of the body.
Stage 1 lung cancer is considered early-lung cancer, meaning that the tumor is relatively small and hasn’t spread to lymph nodes or any other part of the body, so the N and M are not factors.
Most stage 1 lung cancers are non-small cell lung cancer (NSCLC). NSCLC accounts for about 80 to 85 percent of lung cancer cases, according to the American Cancer Society (ACS).
Small cell lung cancer (SCLC) accounts for about 10 to 15 percent of lung cancer cases. It’s a faster growing form of cancer and spreads to other parts of the body earlier. One-third of these are found during an early stage, according to the American Society of Clinical Oncology. Rather than using the TNM system, these cancers are referred to as either limited or extensive, rather than being classified by stage.
Stage 1 NSCLC is further classified as either stage 1A or stage 1B, depending primarily on the size of the tumor.
With stage 1A lung cancer, the tumor is 3 centimeters or smaller and confined to the lung. It’s classified as 1A1, 1A2 or 1A3, again according to the size of the tumor.
With stage 1B, the tumor is larger than 3 centimeters, but smaller than 4 centimeters, and is still confined to the lung. Smaller tumors may also be considered stage 1B lung cancer if they’ve spread to the main airway (bronchus) or to the innermost layer of the membrane covering the lung. The disease may also be classified as stage 1B if part or all of the lung has collapsed or become inflamed.
Most early lung cancers don't have symptoms and are found during a routine screening. When stage 1 lung cancer does cause symptoms, they may include:
Treatment of stage 1 lung cancer typically involves some combination of surgery, targeted therapy and chemotherapy or, for those who can’t undergo surgery, radiation therapy.
The types of surgery performed to treat stage 1 lung cancer include:
Lobectomy: During this procedure, the surgeon removes the lobe of the lung affected by lung cancer. This is the most common lung cancer surgery.
Segmental resection: Also called a segmentectomy, this procedure removes one to four segments of the lungs’ lobe. (Each lung lobe comprises two to five lung parts.)
Sleeve resection: Also known as a sleeve lobectomy, this surgery is used to remove the cancerous lobe and part of the main bronchus connected to that lung. The remaining end of the bronchus is then connected to an unaffected lobe.
Other treatments may include:
Targeted therapy: This cancer treatment uses drugs to target very specific genes and proteins involved in the growth and behavior of certain lung cancers. Targeted therapy may be given after surgery.
Radiation therapy, such as stereotactic body radiation therapy: This may be recommended when surgery isn’t possible. This type of radiation uses special equipment to precisely deliver radiation to tumors over several days. Some patients with stage 1 lung cancer may be treated with radiation therapy after surgery as part of a clinical trial.
Chemotherapy: Similar to those who undergo radiation therapy, some patients with stage 1 lung cancer may be treated with chemotherapy after surgery as part of a clinical trial or if they have high risk features for recurrence.
The prognosis for lung cancer that’s caught early tends to be strong. According to the ACS, the five-year relative survival rate is 64 percent for patients with NSCLC that hasn’t spread beyond the lung. This means that 64 percent of patients treated in the recent past for localized lung cancer were alive five years after treatment.