Can Gleason 7 prostate cancer ever be low-risk? Results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.
57 Background: Overtreatment of low-risk prostate cancer (PC) is a major issue. Increasing use of active surveillance (AS) will ease this burden. Limited data are available on including men with intermediate risk PC (i.e. Gleason 7) into AS protocols. We examined if a subset of men with Gleason 7 (3+4) PC could be reasonable AS candidates. Methods: We used SEARCH to identify men who had radical prostatectomy from 2001-13 with >8 cores on biopsy and complete data. We compared men who fulfilled low-risk disease criteria (cT1c/T2a; biopsy Gleason ≤6; PSA ≤10 ng/mL) with the exception of biopsy Gleason 7 (3+4) vs. men who met all 3 low-risk criteria. Logistic regression models were used to test the association between biopsy Gleason 3+4 vs. ≤6 and pathological features. Biochemical recurrence (BCR) was examined using multivariable Cox hazards analysis adjusted for clinical and demographic features. To examine if there was a subset of men with low-volume Gleason 7 who would have comparable outcomes to low-risk men, we repeated all analyses limiting the percent positive cores to ≤ 33% and positive cores to ≤ 4, ≤ 3, or ≤ 2. Results: 885 men met inclusion criteria: 505 had low-risk PC and 380 had Gleason 7 low-risk PC. Overall, the Gleason 7 low-risk men had increased risk of pathological Gleason ≥4+3 (p<0.001), positive margins (p=0.069), extracapsular extension (p<0.001), and seminal vesicle invasion (p<0.001) on univariable analysis. Men in the Gleason 7 low-risk group had significantly higher BCR risk (HR 1.65, p=0.004). Analyses were repeated using increasingly strict definitions of low-volume PC. With the exception of higher pathological Gleason score (p<0.001), at ≤3 positive cores, there was no difference in adverse pathological features between groups (all p>0.1). Among men with ≤3 positive cores who met the other low-risk criteria (cT1c/T2a; PSA ≤10 ng/mL), BCR risk was similar in men with Gleason 6 or Gleason 7 (3+4) (HR 1.30; p=0.347) PC. Conclusions: Among men with PSA≤10 ng/mL and stage cT1c/T2a, those with Gleason 7 (3+4) PC in ≤3 positive cores have similar rates of adverse pathology and BCR as men with Gleason ≤6 PC. This finding may expand inclusion criteria of AS protocols to reduce PC overtreatment.