1 Background: Active surveillance (AS) is an accepted management strategy for localized prostate cancer. However, the rate of pathological upgrading has not been well described in mature study cohorts. Furthermore, concern exists over the possibility of prostate cancer dedifferentiation with time in patients on AS. Methods: Patients in our prospectively collected AS database with at least one repeat prostate biopsy were included. Linear regression analysis was used to estimate the proportion of patients upgraded (Gleason 6 to 3+4 or higher, Gleason 3+4 to 4+3 or higher) with time from diagnostic biopsy. Results: 593 of 862 patients in our cohort had at least one repeat biopsy. Median follow-up was 6.4 years (max. 20.2 years). The total number of biopsies ranged from 2 to 6. 20% of patients were intermediate risk, 0.3 % high risk, all others low risk. 31.2% of patients were upgraded during active surveillance. The proportion of patients upgraded increased with time, suggesting prostate cancer dedifferentiation occurred at a rate of 1.0%/year (95%CI -0.12 to 2.16%/year). The estimated rate of increase was 2.5 times higher in patients with intermediate risk disease at diagnosis (rate 1.9%/year, 95%CI -0.7-4.6) compared with those with low risk disease (rate 0.75%/year, 95%CI -0.5-2.0). Further analysis is underway. 62% of upgraded patients (n=114) went on to have active treatment. Patients who were upgraded and treated had significantly greater PSA velocities (median 1.2 ng/ml/y vs 0.42 ng/ml/y, p=0.01) and significantly higher Gleason scores when upgraded, than those who remained on surveillance (21.8% vs 2.8% Gleason 8-10, p<0.01). Conclusions: This is the largest re-biopsy cohort, with long-term follow-up, described to date, enabling the first estimates of prostate cancer dedifferentiation in patients on AS. Dedifferentiation rates appear higher in patients with intermediate risk prostate cancer compared with those who are low risk at baseline.
Re: Long-term Follow-up of a Large Active Surveillance Cohort of Patients with Prostate Cancer