Lung with a tumor on it

Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most common form of lung cancer, accounting for 80 to 85% of all cases of lung cancer. There are different stages of NSCLC, ranging from 0 to 4; higher-numbered stages indicate the cancer has spread further and tumors are larger.

Symptoms and treatment options depend on the stage of your lung cancer along with what type of NSCLC you're diagnosed with. There are three primary types: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.  

Lung cancer remains a difficult disease to completely overcome. However, improvements in screening are enabling doctors to catch lung cancer earlier than in previous generations, and advancements in treatments have been improving survival rates for all stages of NSCLC.

Frequently Asked Questions

  • Does smoking cause non-small cell lung cancer?

    Smoking is still the leading cause of non-small cell lung cancer, but there are other significant risk factors. Secondhand smoke accounts for approximately 7,330 deaths from lung cancer per year. Radon exposure is the leading cause of lung cancer in nonsmokers. Family history, occupational exposures, lung disease (such as COPD), and air pollution also contribute.

  • What are the stages of non-small cell lung cancer?

    Staging can help determine the spread of the disease and inform treatment.

    Stage 0/In situ: Known as precancer. Typically no symptoms. 

    Stage 1: Tumor is invasive but has not spread to lymph nodes.

    Stage 2: Cancer is localized to one lung/lymph nodes on that side of the lung.

    Stage 3: Cancer is larger, or has spread to different lymph nodes than stage 2 or to nearby tissues.

    Stage 4: Metastatic; cancer has spread to the other lung, further in the affected lung, or other parts of the body.

  • Is non-small cell lung cancer curable?

    In general, non-small cell lung cancer may be curable if it is localized (up to stage 3). Unfortunately, although cure is possible in the majority of patients with stage 0, at present, only a minority of patients with stage 3 are cured. Many treatment options are available, including local and systemic methods. Treatments are most successful when cancer is detected early. However, not all types of NSCLC show early symptoms, making diagnosis difficult.

Key Terms

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Page Sources
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  1. American Cancer Society. What is lung cancer? Updated October 1, 2019.

  2. U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. 2014.

  3. American Cancer Society. Signs and symptoms of lung cancer. Updated October 1, 2019

  4. Wang Y, Pang Z, Chen X, Yan T, Liu J, Du J. Development and validation of a prognostic model of resectable small-cell lung cancer: a large population-based cohort study and external validation. J Transl Med. 2020;18(1):237. doi:10.1186/s12967-020-02412-x

  5. National Cancer Institute. Cancer staging. Updated March 9, 2015.

Additional Reading