D’Amico Risk Categories

Last Modified: June 29, 2008

Dear OncoLink "Ask The Experts,"

Can you describe the D'Amico risk categories and how they relate to prognosis ?

Richard Whittington, MD, Associate Professor of Radiation Oncology at the University of Pennsylvania School of Medicine, responds:

Dr. Anthony D'Amico has shown that it is possible to estimate the biologic aggressiveness of prostate cancers by grouping them into different risk categories, which in turn reflect the risk of cancer growth and spread. When an urologist does a prostate biopsy, he systematically samples the gland from 6 to 12 – and sometimes up to 24 – different areas. The number of involved areas out of the total number sampled is a term called “percent positive biopsies (or cores)”, and indicates how much of the prostate gland is involved with cancer. For example, Dr. D’Amico has found that a tumor that only involves a small percentage of cores can be classified as low risk, whereas a high percentage of positive cores portends a worse prognosis.

Below is the overall risk stratification of this system:

Low risk:
PSA < 10ng/ml and Gleason < 6 and
The percentage of involved cores is < 50% or
Intermediate risk with only 1 positive core

Intermediate risk:
Gleason score of 7 or PSA of 10-20
Low risk with > 50% of positive cores or
High risk and only 1 positive core

High risk:
Gleason > 8 or PSA > 20 and more than 1 positive core
Or intermediate risk and more than 50% positive cores

When there is a conflict in the Gleason score and PSA risk group, the worse factor wins and determines the risk category assignment. For example, a patient with a low Gleason Score of 6 combined with a PSA of 25 ng/ml is considered high risk. The exception to this would be, say, if there is only one positive core out of all of the ones sampled, in which case the risk category goes down to intermediate risk.