Stage I Non-Small Cell Lung Cancer

Stage I Lung Cancer: Definition, Treatments, and Prognosis

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Stage I lung cancer is the earliest stage at which most lung cancers are diagnosed and the stage where long-term survival is the longest. About 30 percent of non-small cell lung cancers are detected when they are still at stage I or II. (There is an early stage of lung cancer, stage 0 lung cancer or carcinoma-in-situ, though lung cancer is rarely found at this very earliest and non-invasive stage.)

There are two main types of lung cancer: non-small cell and small cell lung cancer. Non-small cell lung cancer is the most common type of lung cancer, it usually grows and spreads more slowly than small cell lung cancer, and it consists of three common types: squamous cell carcinoma, large cell carcinoma, and adenocarcinoma.

Other less common types of non-small cell lung cancer are pleomorphic, carcinoid tumor, salivary gland carcinoma, and unclassified carcinoma.


Understanding the stage of a lung cancer is very important—both for determining the best treatment options, and to have an idea of what the future holds as far as prognosis. Stage I lung cancer is localized, which means it has not spread to any lymph nodes or other organs. Stage I is further broken down into:

  • Stage IA: The tumor is less than 3 cm (about 1 ½ inches)
  • Stage IB: The tumor is greater than 3 cm and less than or equal to 5 cm

Your oncologist might describe the stage of your cancer based on something called the TNM system, where T stands for tumor size, N stands for nodes, and M stands for metastasis (the spread of cancer). According to the TNM system, stage 1 lung cancer would be described as:

  • Stage IA (T1N0M0): Meaning a tumor less than 3 cm, with no nodes and no metastasis
  • Stage IB (T2N0M0): Meaning a tumor greater than 3 cm, but less than or equal to 4cm, with no nodes and no metastasis


Stage I lung cancer can be present without any symptoms and is often picked up incidentally when an x-ray is done for another reason. Sometimes, stage I lung cancer is found when an individual at risk for lung cancer undergoes CT screening for lung cancer. Common symptoms when present may include a persistent cough, shortness of breath or recurrent episodes of pneumonia or bronchitis. Since the cancer has not spread, symptoms such as major fatigue, unintentional weight loss, or significant pain are usually absent.


Treatments for stage I lung cancer depend on whether surgery is possible (in some circumstances it may not be) and may also include adjuvant chemotherapy to reduce the risk of recurrence.


Surgery is the treatment of choice for stage I lung cancer. There are three major types of lung cancer surgery performed for lung cancer, though sometimes surgery is not possible due to the location of the tumor or your general health condition. A technique called video-assisted thoracoscopic surgery (VATS) is less invasive than traditional surgery and better tolerated. Not all lung cancers can be removed via this method, but when they can be, recovery is significantly shorter. Not all lung cancer surgeons perform this technique. In addition, it's been found that people who undergo lung cancer surgery at cancer centers which do a greater volume of these surgeries may have better outcomes. If you are considering lung cancer surgery, it's important to get a second opinion. Many people choose to get these opinions at one of the larger National Cancer Institute-designated cancer centers. 

Options for Inoperable Stage I Lung Cancer

For patients with inoperable stage I lung cancer, radiation therapy is an option that can sometimes result in a cure. A new technique called stereotactic body radiotherapy (SBRT) appears quite promising for those who are unable to go through surgery for stage 1 lung cancer for whatever reason. Proton beam therapy may also be an option for those with early-stage lung cancer which is difficult or impossible to remove via surgery.

Adjuvant Chemotherapy and/or Radiation Therapy

With stage IA lung cancer, chemotherapy or radiation therapy is not usually recommended, but may be considered if molecular characteristics of the tumor suggest that it has a high risk of recurrence. With stage IB lung cancer, based on some aggressive features of the tumor (poorly differentiated tumors, for example) some oncologists recommend adjuvant chemotherapy—chemotherapy that is started shortly after surgery in an attempt to kill any cancer cells that remain after surgery.

The decision as to whether adjuvant treatment is needed has been challenging historically. A 2019 study published in the Journal of Thoracic Oncology suggests that blood tests for cell-free DNA (cfDNA), or pieces of cancer cells that break off and are found in the blood via a liquid biopsy, may help determine which people have minimally residual disease (cancer cells left over after surgery) and would benefit from chemotherapy and/or radiation after surgery.

Recurrence After Stage I Lung Cancer Treatment

Even with successful surgery, stage 1 lung cancer recurs either locally or at distant sites in roughly a third of patients. If stage 1 lung cancer recurs, another surgical procedure may be recommended, or further treatment with chemotherapy and radiation. Several clinical trials are in progress to evaluate treatment options after a recurrence of early-stage lung cancer.

In those that have smoked in the past, there is also a risk of developing a second primary tumor related to smoking, either in the lungs or in other regions of the body.

Survival Rate and Prognosis of Stage I Lung Cancer

The overall five-year survival rate for stage 1 lung cancer at this time is approximately 61%. Recent studies have shown survival rates in the range of 90 percent when stage I lung cancer is found with CT screening, and hopefully, screening methods will be developed soon to improve early detection and overall survival.


Studies suggest that learning as much about your disease as possible can improve your outcome. Ask questions. Seek the support of loved ones and involve them in your care decisions. Find a support group or support community. If you don't have a support group in your region, there are many online support communities which are very active. If you are looking for these, the hashtag #LCSM stands for lung cancer social media and can help you find others who are facing a similar situation. Learn about clinical trials. But remember that the decisions you make belong to you alone, and those close to you need to support you in your journey.

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