Is prostate specific antigen (PSA) density necessary in selecting prostate cancer patients for active surveillance and what should be the cutoff in the Asian population?

Background: To investigate the role of Prostate Specific Antigen density (PSAD) in selecting prostate cancer patients for active surveillance (AS) and to determine a cutoff PSAD in identifying adverse pathological outcomes.
Methods: Data from 287 patients who underwent radical prostatectomy for prostate cancer were retrospectively reviewed. Six different AS protocols, the University of Toronto; Royal Marsden; John Hopkins; University of California San Francisco (UCSF); Memorial Sloan Kettering Cancer Center (MSKCC) and Prostate Cancer Research International: Active Surveillance (PRIAS), were applied to the cohort. Pre-operative demographics and pathological outcomes were analysed. Statistical analyses on the predictive factors of adverse pathological outcomes and significance of PSAD were performed. A cutoff PSAD with best balance between sensitivity and specificity in identifying adverse pathological outcome was determined.
Results: PSAD predicted adverse pathological outcomes better than Prostate Specific Antigen (PSA) level alone. The PSAD was significantly lower (0.12-0.13 ng/dl/ml) in protocols including PSAD (the John Hopkins and PRIAS) compared with the other four protocols not including PSAD as a selection criteria (0.21-0.25 ng/dl/dl, P  = 0.00). PSAD predicted adverse pathological outcomes in all protocols not incorporating PSAD as an inclusion criteria ( P  = 0.00-0.02). By the receiver operator characteristics curve analysis, it was found that a PSAD level of 0.19 ng/ml/ml had the best balance between sensitivity and specificity in predicting pathological adverse disease (Area under curve = 0.63, P  = 0.004).
Conclusion: PSAD is necessary in selecting prostate cancer patients for active surveillance. It predicts adverse pathological outcomes in patients eligible for active surveillance better than PSA level alone. A PSAD cutoff at 0.19 ng/ml/ml has the best balance between sensitivity and specificity in predicting pathological adverse disease. We recommend using AS protocol incorporating PSAD as a selection criteria (in particular the PRIAS protocol with a cutoff PSAD at 0.2 ng/ml/ml) when recruiting prostate cancer patients for AS.