Grading kidney cancer
To find out the grade of kidney cancer, the pathologist looks at a tissue sample from the tumour under a microscope. The pathologist gives kidney cancer a grade from 1 to 4. The lower the number, the lower the grade.
The grade is a description of the differentiation of the cancer cells. Differentiation is how the cancer cells look and behave compared to normal cells.
Low grade means that the cancer cells are well differentiated. They look and act much 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 and act less normal, or more abnormal. Higher grade cancer cells tend to grow more quickly and are more likely to spread.
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 how you might respond to treatment.
Doctors use 2 grading classifications for kidney cancer.
The International Society for Urological Pathology (ISUP) grading classification uses a scale from 1 to 4 to grade both clear cell (conventional) and papillary renal cell carcinomas. The ISUP system is also used to help estimate survival.
The Fuhrman grading system is older than the ISUP grading system. It also uses grades 1 to 4. It is most accurate for clear cell renal cell carcinoma.