AUA 2020 Review: Using Biomarkers in Patients with a Positive Multiparametric MRI: 4Kscore Predicts Presence of Cancer Outside the Index Lesion - Thomas Keane
June 25, 2020
Thomas E. Keane, MBBCh, FRCSI, FACS, Department of Urology, The Medical University of South Carolina, Charleston, South Carolina, USA.
AUA 2020 Conference Coverage
Tom Keane: This is Tom Keane coming to you from UroToday and the Medical University of South Carolina in Charleston. I'm continuing my review of markers one for prostate cancer. This is Moderated Poster Session 9. This abstract is number MP09-09. It's entitled, "Using Biomarkers in Patients with a Positive Multiparametric MRI: 4Kscore Predicts Presence of Cancer Outside the Index Lesion." The primary author is Anna Lantz and this comes from Ash Tewari's group in New York.
So EAU guidelines recommend multiparametric MRI before a confirmatory prostate biopsy. In positive multiparametric MRIs, and they define that as the PI-RADS lesion of greater than three, targeted biopsy and systematic biopsy should be performed. Even if this strategy leads to higher chances of diagnosing clinically significant prostate cancer, it is associated with both an increased number of biopsies and higher detection of indolent disease.
The aim of this study was to evaluate if the blood marker, or biomarker 4K score, in addition to multiparametric MRI information, could identify patients who would benefit from performing only a targeted biopsy. The authors retrospectively analyzed the population of 256 men who underwent systematic biopsy and targeted biopsy at their institution to develop a multivariate logistic regression model, including 4Kscore and PI-RADS-V2 score to predict ISUP-grade group greater than or equal to 2 prostate cancer in the systemic biopsy.
At univariate analysis, prior biopsy status, rectal exam, PSA, PSA density, prostate volume, PI-RADS-V2 score, multiparametric MRI index lesion volume, and 4Kscore emerged as predictors of clinically significant prostate cancer at systematic biopsy. In the multivariate analysis, the model showing the best performance included 4Kscore and PI-RADS-V2 scores. To avoid the risk of collinearity with 4Kscore, prior biopsy status, and DRE were not included in the multivariate analysis, and the table is provided.
The developed model demonstrated an area under the curve of 0.87. Performing only targeted biopsies in patients with a model derived probability of less than 12.5% resulted in 39.5% or 110 patients who underwent fewer systematic biopsies and 33% reduction of detecting Gleason group 1 disease while measuring Gleason grade greater than or equal to 2, in 5.2% there were four patients using systematic biopsy only, and only 1% using systematic biopsy and targeted biopsy.
Decision curve analysis showed the net clinical benefit of the model compared to systematic biopsy in all, and no systematic biopsy strategies in a wide range of probability. And that is also shown in the figure.
So in conclusion, 4Kscore in combination with multiparametric MRI can help to reduce unnecessary systematic biopsies and decrease detection of clinically insignificant prostate cancer. Again, a very interesting abstract, which may well help define who needs treatment from who does not need it and who is likely to progress active surveillance. Thank you.