Grading non-melanoma skin cancer
To find out the grade of non-melanoma skin cancer, the pathologist looks at a tissue sample from the skin under a microscope. The pathologist may give non-melanoma skin cancer a grade from 1 to 4. The lower the number, the lower the grade.
The grade is a description of how the cancer cells look and act compared to normal cells. How different the cancer cells are is described as differentiation.
Low grade means that the cancer cells are well differentiated. They look almost like normal cells. Lower grade cancer cells tend to be slow growing and are less likely to spread.
High grade means that the cancer cells are poorly differentiated or undifferentiated. They look less normal, or more abnormal. Higher grade cancer cells tend to grow more quickly and are more likely to spread than low-grade cancer 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. This helps them plan your treatment. The grade can also help the healthcare team predict your prognosis and how the cancer might respond to treatment.
For non-melanoma skin cancer, the grade is included as a part of staging. Staging describes the size of the cancer and where it is in the body. High-grade non-melanoma skin cancers are usually given a higher stage.
American Joint Committee on Cancer. AJCC Cancer Staging Handbook. 7th ed. Chicago: Springer; 2010.