Stages and grades 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 called limited and extensive stage, for small cell lung cancer. Doctors are starting to use this less frequently, as we learn more about small cell lung cancer.

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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.

For most lung cancers, there isn’t a specific grading system doctors use. But generally:

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: 
28 Jan 2020
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