Outcome following active surveillance of men with screen-detected prostate cancer. Results from the Göteborg randomised population-based prostate cancer screening trial

Abstract

Background: Active surveillance (AS) has emerged as a treatment strategy for reducing overtreatment of screen-detected, low-risk prostate cancer (PCa).

Objective: To assess outcomes following AS of men with screen-detected PCa.

Design, setting, and participants: Of the 968 men who were diagnosed with screen-detected PCa between 1995 and 2010 in the Göteborg randomised, population-based PCa screening trial, 439 were managed with AS and were included in this study. Median age at diagnosis was 65.4 yr of age, and median follow-up was 6.0 yr from diagnosis.

Intervention: The study participants were followed at intervals of 3-12 mo and were recommended to switch to deferred active treatment in case of a progression in prostate-specific antigen, grade, or stage.

Outcome measurements and statistical analysis: The end points-overall survival (OS), treatment-free survival, failure-free (no relapse after radical treatment) survival, and cancer-specific survival-were calculated for various risk groups (very low, low, intermediate, and high) with Kaplan-Meier estimates. A Cox proportional hazards model as well as a competing risk analysis were used to assess whether risk group or age at diagnosis was associated with failure after AS.

Results and limitations: Forty-five per cent of all screen-detected PCa were managed with AS, and very low-risk and low-risk PCa constituted 60% of all screen-detected PCa. Thirty-seven per cent (162 of 439) switched from surveillance to deferred active treatment, and 39 men failed AS. The 10-yr OS, treatment-free survival, and failure-free survival were 81.1%, 45.4%, and 86.4%, respectively (Kaplan-Meier estimates). Men with low-, intermediate-, and high-risk tumours had a hazard ratio for failure of 2.1 (p=0.09), 3.6 (p=0.002), and 4.6 (p=0.15), respectively, compared to very low-risk tumours (Cox regression). Only one PCa death occurred, and one patient developed metastasis (both in the intermediate-risk group). The main limitation of this study is the relatively short follow-up.

Conclusions: A large proportion of men with screen-detected PCa can be managed with AS. AS appears safe for men with low-risk PCa.