Objective: To report the results of a prospective study of active surveillance of untreated prostate cancer, with a focus on baseline predictors of prostate-specific antigen (PSA) velocity, as PSA velocity before treatment is an important predictor of prostate cancer mortality, and patients on active surveillance are monitored for several years to estimate the PSA velocity and thus select patients for radical treatment.
Patients and methods: A prospective study of active surveillance for localized prostate cancer opened at the Royal Marsden Hospital in 2002. Eligible patients had clinical stage T1/T2a, N0/Nx, M0/Mx adenocarcinoma of the prostate with a serum PSA level of < 15 ng/mL, a Gleason score of < or = 7 with primary grade < or = 3, and less than half the biopsy cores positive. The PSA velocity before treatment was analysed in relation to baseline clinical characteristics.
Results: In all, 237 patients on surveillance were followed for a median of 24 months (median age 67 years; median initial PSA level 6.5 ng/mL; median pretreatment PSA velocity 0.44 ng/mL per year). On multivariate analysis, PSA density (i.e. serum PSA level/prostate volume) was the only significant determinant of PSA velocity (P < 0.001). Patients with a PSA density above or below the median (0.185 ng/mL/mL) had a median (interquartile range) PSA velocity of 0.92 (0.34-1.77) ng/mL per year and 0.35 (-0.06, 0.80) ng/mL per year, respectively.
Conclusions: PSA density, which is readily available at the time of diagnosis, is an independent determinant of PSA velocity in untreated, localized prostate cancer. If this is confirmed, PSA density could be used to inform the often difficult choice between active surveillance and immediate radical treatment.