Follow-up in Active Surveillance for Prostate Cancer: Strict Protocol Adherence Remains Important for...

Active surveillance (AS) is a safe treatment strategy for men with low-risk prostate cancer (PC) when performed in a research setting using strict follow-up. However, less is known about the protocol adherence and outcomes for AS in real-world practice.

To evaluate Prostate Cancer Research International Active Surveillance (PRIAS) protocol adherence in a real-world cohort and to relate follow-up intensity to oncological safety.

Patients with biopsy-detected PC diagnosed from 2008 to 2014 treated with AS at six teaching hospitals in The Netherlands.

AS included regular prostate-specific antigen (PSA) testing (every 3-6mo) combined with a confirmatory biopsy 1yr after diagnosis and every 3yr thereafter.

The proportions of patients complying with the PRIAS biopsy and PSA monitoring protocol were determined. We assessed if PRIAS-discordant follow-up was associated with a higher risk of metastasis compared with PRIAS-concordant follow-up using Cox regression analysis. Analysis was performed for separate risk groups (PRIAS-eligible and PRIAS-ineligible) on the basis of the PRIAS inclusion criteria.

Of all patients on AS for >6mo, 706/958 (74%) had PRIAS-concordant PSA monitoring. Overall concordant follow-up (PSA and repeat biopsy) was observed in 415/958 patients (43%). The percentage of patients with overall concordant follow-up varied between hospitals (range 34-60%; p<0.001). Among PRIAS-ineligible patients, PRIAS-discordant PSA monitoring was associated with a higher risk of developing PC metastases during AS compared with patients with concordant follow-up (hazard ratio 5.25, 95% confidence interval 1.02-27.1). In the PRIAS-eligible population, we found no significant differences regarding rates of metastases between patients with discordant and concordant follow-up.

We observed substantial variation in AS follow-up intensity between large urological practices in the Netherlands. Overall, 43% of patients on AS in daily clinical practice receive PRIAS-concordant follow-up. Noncompliance with the PRIAS follow-up protocol was associated with a higher rate of metastasis among PRIAS-ineligible patients, indicating that strict protocol adherence is important when these patients opt for AS.

Fewer than half of patients with prostate cancer on active surveillance are monitored according to the follow-up protocol of the largest ongoing active surveillance study. Lower-intensity monitoring may be less safe for patients who are not in the lowest risk group.