Grading oral cancer

Grading describes how the cancer cells look compared to normal, healthy cells. Knowing the grade gives your healthcare team an idea of how quickly the cancer may be growing and how likely it is to spread.

To find out the grade of oral cancer, a pathologist looks at a tissue sample from the mouth under a microscope. They look at how different the cells look from normal cells (called differentiation) and other features of the tumour such as the size and shape of the cells and how the cells are arranged. They can usually tell how fast a tumour is growing by looking at how many cells are dividing.

The pathologist gives oral cancer a grade from 1 to 3. A lower number means the cancer is a lower grade. Low-grade oral cancer tends to grow more slowly and is less likely to spread. High-grade cancers tend to grow more quickly and are more likely to spread than low-grade cancers.

Grade 1 cancers have cancer cells that are well differentiated or low grade.

Grade 2 cancers have cancer cells that are moderately differentiated.

Grade 3 cancers have cancer cells that are poorly differentiated or high grade.