Downgrading from Biopsy Grade Group 4 Prostate Cancer in Patients Undergoing Radical Prostatectomy for High or Very High Risk Prostate Cancer.

PURPOSE

We examined rates of Grade Group 4 downgrading at radical prostatectomy among men diagnosed with high and very high risk prostate cancer at biopsy.

MATERIALS AND METHODS

A pooled cohort of 1,776 patients from 3 tertiary referral centers who underwent radical prostatectomy for National Comprehensive Cancer Network® high risk (prostate specific antigen greater than 20 ng/ml, or Grade Group 4-5, or clinical stage T3 or greater) or very high risk (primary Gleason pattern 5, or more than 4 biopsy cores with Grade Group 4-5, or 2 or more high risk features) disease from 2005 to 2015 were reviewed. Overall 893 patients with Grade Group 4 disease at biopsy were identified and 726 patients were available for analysis. Multivariable logistic regression models were fit to determine factors associated with downgrading to Grade Group 3 or less at radical prostatectomy.

RESULTS

Overall 333 (45%) cases were downgraded to Grade Group 3 or less at radical prostatectomy. Of these cases 198 (27%) had concordant Grade Group 4 biopsy and radical prostatectomy pathology and 195 (27%) were upgraded at radical prostatectomy to Grade Group 5. Of high risk cases with biopsy Grade Group 4 disease 49% had any downgrading vs 29% of very high risk cases (p <0.0001). Downgrading to Grade Group 2 or less occurred in 16% (98 of 604) of high risk and 7% (8 of 122) of very high risk cases (p <0.01). Downgraded cases had a lower prostate specific antigen, fewer positive biopsy cores and lower clinical stage (p <0.01). On multivariable analysis fewer positive biopsy cores were significantly associated with downgrading at radical prostatectomy (p <0.01).

CONCLUSIONS

In this cohort of patients with high risk/very high risk prostate cancer, downgrading from biopsy Grade Group 4 at radical prostatectomy occurred less frequently than in other published reports. Any downgrading was significantly less common in very high risk compared to high risk patients, and downgrading to Grade Group 2 or less occurred in a minority of cases in high risk and very high risk patients.