When compared to whole gland analysis following prostatectomy, prostate biopsy (Bx) sampling-based PCa diagnosis has a well-documented error. Although PCa Grade Group (GG) upgrading is often discussed, radical prostatectomy (RP)-related PCa GG downgrade and its prognostic consequences are less well known. For a study, researchers sought to determine if the downgrade of PCa GG at RP was related to subsequent tumor behavior.
Patients who received abnormal grades on both Bx and RP specimens were included in the search of the SEER database from 2010 to 2017. After stratifying the patients into the Bx GG>RP GG and Bx GG≤RP GG groups, tumor behavior following therapy was investigated. The survival analysis was performed using Cox regression.
In the study, 99,835 patients were involved. In all, 18,516 patients (18.5%), had their status downgraded from Bx GG to RP GG. About 13,969 (75.4%) of these patients had a downgrade of 1 grade, while 4,547 (24.6%) had a downgrade of 2 or more grades. For any given RP GG, the risk of cancer-specific mortality (CSM) rose when the history of greater Bx GG compared to RP GG, even after adjusting for age, race, preop prostate-specific antigen level, the proportion of positive biopsy cores, and pathologic TNM stages. For every given RP GG, a history of high Bx GG was specifically associated with a 45% higher risk of CSM (hazard ratio=1.45, 95% CI=1.16-1.82, P<0.001).
Downgrading at the time of RP due to a history of greater Bx GG suggested some relevance as a risk-stratification tool for subsequent cancer outcomes following prostatectomy.