AUA 2018: Can Active Surveillance Really Reduce the Harms of PSA Testing? PRIAS-Study Implicates Caution

San Francisco, CA ( Prostate cancer screening using the prostate specific antigen (PSA) serum test has proven controversial in part due to the large burden of over diagnosis and over treatment. Active surveillance has been proposed as a way of mitigating the harms of PSA screening while retaining its potential benefits. In fact, the US Preventative Services Task Force has recently recommended selective PSA screening on the basis of such an approach. Dr. Drost and colleagues report of data from the PRIAS study, focusing on the limitations of active surveillance (AS) to achieve such reductions in over treatment.

Using the well annotated PRIAS dataset, the authors identified the first 500 men who were enrolled. These patients were enrolled between 2006-2008 at 30 participating centers across 8 countries. According to study protocol, men were recommended to undergo regular PSA testing, digital rectal examination and prostate biopsy. In the case of disease reclassification (upgrading, upstaging, or an increase in tumor volume) or a PSA-doubling time of less than 3 years, men were recommended to undergo definitive management. In this descriptive study, the authors report on the time that men stayed on AS, reasons for discontinuing AS, and rates of potentially unnecessary biopsies and treatments. 

Over a median follow-up of 10.9 years, 325 (65%) men discontinued AS. The median time from enrollment to discontinuation was 2.3 years. A further 121 (24%) men had no clinical data within the past 1 year, though data became unavailable at a median of 7.3 years since enrollment. Only 54 men (11%) could be confirmed to remain on AS.

The majority of men discontinued AS for protocol-driven reasons (upgrading, upstaging, an increase in tumor volume, or elevated PSA-velocity); however, 22% discontinued for other reasons. The majority of biopsies performed during follow-up (79-90%) did not lead to reclassification.

Of the 325 men who discontinued AS, 112 underwent radical prostatectomy, 125 underwent radiotherapy, 57 switched to watchful waiting or died, and treatment details could not be ascertained for 31. 30 men died during the study interval, 1 of prostate cancer.

While the authors suggest that the ability of AS to reduce the harms from PSA testing may be overstated, the limitations of this analysis must be considered. First, these men were enrolled in in 2006-2008. Thus, much of the reclassification is not disease progression, but rather an initial misclassification. The increased utilization of MRI prior to biopsy is likely to diminish both rates of biopsy for patients with clinically insignificant disease, and reduce this initial misclassification. Further, MRI is being used in AS protocols to reduce the burden of biopsy. Finally, enrolling over a similar (or even earlier) time, the ProtecT trial showed that nearly 50% of enrolled patients remained on a conservative treatment strategy at 10 years post enrollment. 

At the conclusion of the presentation, the audience highlighted that, for men who eventually transitioned from surveillance to treatment, many person-years of morbidity were avoided due to delaying the time to intervention. Thus, even for those who eventually reclassify, surveillance may offer a quality of life benefit.

Presented by: Frank-Jan Drost, Erasmus MC, Department of Urology and Radiology

Co-authors: Antti Rannikko, Riccardo Valdagni, Tom Pickles, Yoshiyuki Kakehi, Monique Roobol, for the PRIAS-study group

Written by: Christopher J.D. Wallis, Urology Resident, University of Toronto @WallisCJD on Twitter at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA