Upgrading and Downgrading of Prostate Needle Biopsy Specimens: Risk Factors and Clinical Implications

Abstract

The prostate biopsy Gleason grade frequently differs from the radical prostatectomy (RP) grade. Given the critical role that needle biopsy plays in treatment decisions, we sought to determine the risk factors for upgrading and downgrading the prostate biopsy specimen. We determined the significant predictors of upgrading (worse RP grade than biopsy grade) and downgrading (better RP grade than biopsy grade) among 1113 men treated with RP from 1996 to 2005 within the Shared Equal Access Regional Cancer Hospital (SEARCH) database who had undergone at least sextant biopsy. The Gleason sum was examined as a categorical variable of 2 to 6, 3+4, and 4+3 or greater. Overall, the disease of 299 men (27%) was upgraded and 123 (11%) was downgraded, and 691 men (62%) had identical biopsy and pathologic Gleason sum groups. Upgrading was associated with adverse pathologic features (P < or = 0.001) and the risk of biochemical progression (P = 0.001). Downgrading was associated with more favorable pathologic features (P < or = 0.01) and a decreased risk of progression (P = 0.04). On multivariate analysis, greater prostate-specific antigen levels (P < 0.001), more biopsy cores with cancer (P = 0.001), and obesity (P = 0.003) were all significantly and positively associated with upgrading. In contrast, biopsy Gleason sum 3+4 (P = 0.001) and obtaining eight or more biopsy cores (P = 0.01) were associated with a lower likelihood of upgrading. Men whose disease was upgraded were at a greater risk of adverse pathologic features and biochemical progression. Men with "high-risk" cancer (greater prostate-specific antigen levels, more positive cores, and obese) were more likely to have their disease category upgraded, and obtaining more biopsy cores reduced the likelihood of upgrading.