Predicting the probability of deferred radical treatment for localised prostate cancer managed by active surveillance

Abstract

Objectives: Outcome data from a prospective study of active surveillance of localised prostate cancer were analysed to identify factors, present at the time of diagnosis, that predict subsequent radical treatment.

Methods: Eligible patients had clinical stage T1-T2a, N0-Nx, M0-Mx adenocarcinoma of the prostate with serum PSA<15 ng/ml, Gleason score <or= 7, primary Gleason grade <or= 3, and % positive biopsy cores (pbc) <or= 50%. Monitoring included serial PSA measurement and repeat prostate biopsies. Radical treatment was initiated in the event of biochemical progression (PSA velocity > 1 ng/ml/yr) or histological progression (primary Gleason grade >or= 4, or %pbc > 50%). Multivariate Cox regression analysis of baseline variables was performed with respect to time to radical treatment.

Results: The 326 men recruited from 2002 to 2006 have been followed for a median of 22 mo. Median age was 67 yr, and median initial PSA (iPSA) 6.4 ng/ml. Sixty-five patients (20%) had deferred radical treatment, 16 (5%) changed to watchful waiting because of increasing comorbidity, 7 (2%) died of other causes, and 238 (73%) remain on surveillance. On multivariate Cox regression analysis, the free/total PSA ratio (p<0.001) and clinical T stage (p=0.006) were independent determinants of time to radical treatment.

Conclusions: In addition to established prognostic factors, the free/total PSA ratio may predict time to radical treatment in patients with untreated, localised prostate cancer managed by active surveillance. This possibility warrants further study.