Vickers et al.,1 have previously demonstrated that a baseline PSA at 45- 50 is strongly predictive of a man’s risk of advanced prostate cancer up to 30 years later. Indeed as seen below, there is a 10 fold increase risk for metastasis in men with the highest 10th baseline PSA (> 1.6).
Yet this study is based on retrospective data. And it is not clear if one single test at age 45 to 50 completely rules out the risk of malignancy later in life.
Based on this study the German authors initiated the PROBASE study (Risk-adapted prostate cancer early detection study based on a “baseline” PSA value in young men), a prospective multicenter, randomized trial.
They recruited patients from four different sites in Germany.
They accrued 46,642 patients between 2014-2019.
The trial design is shown below.
Men in arm A were offered immediate PSA testing while men in arm B underwent DRE and deferred PSA testing at age 50.
Based on prior studies, the estimated the above breakdown of risk stratification based on baseline PSA.
The main preliminary results are summarized below:
Key points:
- The expected proportions of low, intermediate and high risk were pretty accurate (89.2%, 9.3%, 1.5%) for Arm A
- Only 179 of the initial 344 high risk men had a repeat PSA that remained above 3.0. Of these, 120 men underwent biopsy.
- Only 0.2% of men in Arm A had prostate cancer (48 out of 23,201)
- Of these men, 75% were either GG1 or favorable intermediate risk PCa
They have not yet gotten to baseline PSA testing in the men in Arm B. Only 57 men had a suspicious DRE warranting initial biopsy, with only 2 (0.03%) being diagnosed with prostate cancer (both GG1).
He concludes the following:
- The distribution of baseline PSA values in PROBASE matched almost exactly that of other cohorts and allows us to define different risk groups and screening intervals
- Further diagnostic testing in young men should only be initiated if an increased PSA level is confirmed by second test
- The prevalence of prostate cancers at eight forty-five is very low
- The prevalence of unfavorable prostate cancer at age 45 is even lower
Presented by: Christian Arsov, Heinrich-Heine-University Duesseldorf, Dusseldorf, Germany
Written by: Thenappan (Thenu) Chandrasekar, MD – Urologic Oncologist, Assistant Professor of Urology, Sidney Kimmel Cancer Center, Thomas Jefferson University, @tchandra_uromd on Twitter during the 2021 European Association of Urology, EAU 2021- Virtual Meeting, July 8-12, 2021.
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