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Stages and grades

Find out about the staging and grading of lung cancer

Stages of lung cancer

The stage of a cancer tells you how big it is and whether it has spread. Knowing the stage can help your doctor decide which treatment you need.

The tests and scans you have to diagnose your cancer give some information about the stage. Sometimes it’s not possible to be certain about the stage of a cancer until after surgery.

Doctors can use a number system or the TNM system to stage your cancer. There is also a simplified staging system for a type of lung cancer called small cell lung cancer.

Find out about

Grades of lung cancer

Grading is a way of dividing cancer cells into groups based on how the cells look under a microscope. This gives you and your doctors an idea of how quickly or slowly the cancer might grow and whether it is likely to spread.

There are 2 main types of lung cancer: non small cell lung cancer and small cell lung cancer. Grading is not used for small cell lung cancer.

Grades of non small cell lung cancer

Grade 1

The cells look very like normal cells. They tend to be slow growing and are less likely to spread than higher grade cancer cells. They are called low grade.

Grade 2

The cells look more abnormal and are more likely to spread. This grade is also called moderately well differentiated or moderate grade.

Grades 3 and 4

The cells look very abnormal and not like normal cells. They tend to grow quickly and are more likely to spread. They are called poorly differentiated or high grade.

Last reviewed: 
31 Jul 2017
  • TNM Classification of Malignant Tumours (8th edition)
    International Union Against Cancer   
    LH Sobin, MK Gospodarowicz, Ch Wittekind
    John Wiley and Sons, Hoboken, New Jersey, 2017

  • AJCC Cancer Staging Manual (8th Edition)
    American Joint Committee on Cancer, 2017

  • The IASLC Lung Cancer Staging Project: Proposals for Revision of the TNM Stage Groupings in the Forthcoming (Eighth) Edition of the TNM Classification for Lung Cancer
    Peter Goldstraw and others for the Study of Lung Cancer Staging and Prognostic Factors Committee
    Journal of Thoracic Oncology, 2015, vol.11, No.1:39-51

  • The Prognostic Significance of Grading in Lung Adenocarcinoma
    Barletta and others Cancer 2010, 116.3: pages 659–669

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