About 270,000 men are diagnosed with prostate cancer every year. Largely due to the effects of PSA-based prostate cancer screening, the majority of these cancers are diagnosed at an early stage. While some prostate cancers are aggressive and have the potential to metastasize, others are slow-growing and pose minimal threat to the patient.
A critical part of prostate cancer treatment is estimating the risk that the cancer poses to the patient. This assessment includes characteristics of the cancer itself and characteristics of the patient, such as age and health. The primary method for characterizing the aggressiveness of a prostate cancer is to consider a patient’s PSA value, the findings on digital rectal exam (DRE), and the Gleason Grade Group (GGG) on the prostate biopsy.
Gleason Grade Group
The Gleason Grade Group, formerly known as the Gleason Score or Gleason Sum, reflects the aggressiveness of the prostate cancer, with higher grades indicating more aggressive disease, as follows:
- Grade group 1 (GG1): 3+3=6
- Grade group 2 (GG2): 3+4=7
- Grade group 3 (GG3): 4+3=7
- Grade group 4 (GG4): 4+4=8
- Grade group 5 (GG5): 4+5=9, 5+4=9, 5+5=10
Using PSA, DRE and GGG, patients are categorized into three risk groups:
- Low risk: PSA <10 AND DRE T1c-T2a AND GG1
- Intermediate risk: PSA 10-20 OR DRE T2b-T2c OR GG2-3
- High risk: PSA >20 OR DRE ≥ T3 OR GG4-5
While treatment decisions are made on an individual basis, doctors often consider a patient’s risk group when recommending a treatment. There are additional tests that may provide more information about the aggressiveness of a patient’s prostate cancer, including imaging (MRI, CT, bone scan, PET scan) and genomic testing (OncotypeDx, Prolaris, Decipher).