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

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 ≤ 7, primary Gleason grade ≤ 3, and % positive biopsy cores (pbc) ≤ 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 ≥ 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.