Many men, when told they have a Gleason score 6 cancer, worry that their prognosis is bad because the number 6 seems high. But doctors actually consider Gleason score 6 to have an excellent prognosis even without treatment. This “mismatch” between perception and reality might lead a man to choose a more aggressive treatment than he really needs.
In addition, a Gleason score of 7 is associated with two different prognoses. The cure rate for a man with a Gleason score of 3+4=7 is more than 85 percent after surgery. But it drops to 65 to 70 percent for Gleason 4+3=7 cancer because there are more grade 4 cells. Furthermore, Gleason scores of 8, 9, and 10 are all typically viewed as “bad” and “highly aggressive.” But approximately 60 percent of men with Gleason score 8 cancer have long-term disease-free intervals, compared with about 30 percent of those with Gleason score 9 and 10 cancers.
To help clear up the confusion, many pathology reports now classify Gleason scores into the following groups based on prognosis.
- Grade group 1: Gleason score 6 (most favorable)
- Grade group 2: Gleason score 3+4=7
- Grade group 3: Gleason score 4+3=7
- Grade group 4: Gleason score 8
- Grade group 5: Gleason score 9 or 10 (least favorable)