Question: What do the terms "grade" and "stage" mean when applied to VHL kidney tumors? What’s the difference between the two? What does it mean when they say it was a "grade two" tumor?

Answer: Grade and stage, when applied to kidney tumors, are separate but related terms.

Grade refers to the "aggressiveness" of the tumor when the tumor is looked at by the pathologist under the microscope. Kidney tumors can be graded on a 1 to 4 scale, with Grade 1 being the least "malignant appearing" and Grade 4 being the most aggressive appearing. In practice, grade is infrequently used in referring to kidney tumors and is less useful in characterizing a kidney tumor than is stage. A Grade II tumor would be one that is moderately well-differentiated, that is moderately aggressive appearing under the microscope.

Stage of the tumor refers to how advanced the kidney tumor is in the patient. The stage of the kidney

tumor is generally determined by radiographic studies such as CT Scan, Magnetic Resonance Imaging and/or ultrasound. A Stage I kidney tumor is a very small kidney tumor that is totally confined within the kidney. A Stage II tumor is one that has grown out through the lining (capsule) of the kidney. A Stage III tumor is one which has invaded outside the kidney into either the local nodes draining the kidney (the hilar nodes) or into the vena cava (the large vein that goes up to the chest or the renal vein (the vein from the kidney to the vena cava).

-- W. Marston Linehan, M.D., Head, Urologic Oncology Section, National Cancer Institute, Bethesda, Maryland.

As published in the VHL Family Forum 5:2, June 1997. For permission to reprint, please contact VHL Family Alliance, editor@vhl.org. Further information is available from the VHL Family Alliance, info@vhl.org.