Gleason score risk group 8–10 ‘should be subdivided’
MedWire News: The high-risk prostate cancer Gleason score category 8–10 should be subdivided and include Gleason score 7 with tertiary Grade 5, recommend US researchers after finding outcome differences between scores.
The Gleason scoring system, which grades prostate cancer cell samples as having low, intermediate, or high risk based on scores of ≤6, 7, and ≥8, respectively, has become the most widely used grading system. However, there is evidence to suggest that tertiary Grade 5 disease in the context of Gleason score 7 prostate cancer increases the risk for biochemical recurrence.
To investigate further, Akash Nanda, from Brigham and Women’s Hospital in Boston, Massachusetts, and colleagues studied 312 men with T1c–T3N0M0 prostate cancer treated with radical prostatectomy or external beam radiotherapy with or without androgen suppression therapy (AST).
In all, 167 patients had Gleason score 8 without tertiary Grade 5 disease, while 36 had Gleason score 7 with tertiary Grade 5 disease, and 109 had Gleason score 9–10 disease. The median age of the patients was 68 years and the median prostate-specific antigen (PSA) level was 8.9 ng/ml.
Over a median follow-up of 5.7 years, there were 154 PSA recurrences, the team reports in the International Journal of Radiation Oncology Biology Physics.
Men with Gleason score 8 disease had a lower risk for PSA recurrence than those with Gleason score 9–10 disease, at a hazard ratio of 0.74. In contrast, patients with Gleason score 7 with tertiary Grade 5 disease had a similar risk for PSA recurrence compared with those with Gleason score 9–10 disease, at a hazard ratio of 1.08.
The median time to PSA failure was shorter in men with Gleason score 9–10 disease and with Gleason score 7 with tertiary Grade 5 disease than in those with Gleason score 8 disease, at 4.5 years and 5.0 years versus 5.4 years, respectively.
“These data emphasize the importance of substratifying the standard Gleason score category of 8–10 in 8 versus 9, 10, and 7 with tertiary Grade 5 for future randomized studies,” the team says.
“They also suggest... that men with Gleason score 7 with tertiary Grade 5 and locally advanced disease may benefit from long-term AST in addition to definitive radiation therapy.”
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By Liam Davenport