New multistep approach in PCa detection wins EMUC17 prize

18 November 2017

A new multistep approach using a combination of PSA, MRI-targeted biopsies and an innovative test bagged today the top prize for the best oral poster presentation at the 9th European Multidisciplinary Meeting on Urological Cancers (EMUC17) held in Barcelona, Spain.

The Swedish-Norwegian study led by Tobias Nordström bested five other studies for their study titled “A multistep approach for detection of prostate cancer using prostate-specific antigen, the Stockholm 3 Test, and MRI-targeted Biopsies: Initial data from the STHLM3 MRI Project.”  The study looked into a three-pronged process which detects more significant (GS≥7) tumours while reducing overdetection. The teams are from the Stockholm-based Karolinska Institute and the Aleris Cancer Center, Dept. of Urology in Oslo, Norway.

Overdetection, or its opposite (underdetection), are  frequently encountered dilemmas by urologists due to the lack of high–sensitivity tests in prostate cancer diagnosis. As a consequence, repeat biopsies are often done, a less-than-ideal scenario due to complications and cases of infections.

In his presentation, Nordström said the STHLM3 study showed a reduced need for systematic prostate biopsies (SBx) and a lower risk of overdiagnosis when the STHLM3 test (S3M) was used instead of PSA to screen for prostate cancer (PCa).

“Targeted biopsies (TBx) using magnetic resonance imaging (MRI) have been suggested to improve prostate cancer detection chain for PCa detection using: (1) first-line PSA testing; (2) reflex testing with S3M; (3) further work-up using MRI followed by TBx on MRI-positive men,” said Nordström.

The paired design STHLM3 MRI Phase 1 study included men 45-75 yrs without PCa referred for prostate biopsies to any of six Swedish or Norwegian sites. Participants underwent 1.5T MRI using a uniform protocol reported according to PI-RADS v2. All men underwent TBx on lesions with PI-RADS≥3 using locally available fusion techniques (Artemis, Koelis or BioJet), SBx, and blood-sampling for STHLM3 test analysis.

The results showed the study inclusion closed on 1 June 2017, biopsy and blood analysis data was complete for 502 and 319 participants (2017-06-22). 39% of participants with STHLM3 data had <10% risk of Gleason Score (GS) ≥7 cancer on the STHLM3 test. SBx diagnosed 154/187 (82.4%) and TBx 169/187 (90.4%) of the total GS≥7 tumours found in the cohort (p=0.02).

Furthermore, SBx diagnosed 104 and TBx 78 GS6 tumours, a 25% reduction. TBx in men with STHLM3 test≥10% decreased biopsies by 34%, decreased GS6 tumours by 47% and detected 84% (157/187) of total GS≥7 cancers in the cohort. Performing only SBx on men in this cohort requires biopsies on all men to detect 82% of the total GS≥7 tumours.

“Many men undergoing prostate biopsies in today’s clinical system have a low risk of prostate cancer,” the authors wrote.

They concluded: ”TBx detects more GS≥7 and less GS 6 tumours than SBx. A strategy using the STHLM3 test and targeted biopsies decreases overdetection and reduces biopsies at comparable sensitivity as using systematic biopsies on all men.”