SUO 2018: Gene Expression Classifier Utility in Men at High Risk of Recurrence Following Radical Prostatectomy (G-MINOR)

Phoenix, Arizona (UroToday.com) The Decipher assay is a molecular genomic biomarker based on tissue pathology that serves a genomic classifier (GC) for prostate cancer (PCa). It has previously been validated in the post-radical prostatectomy (RP) setting as a predictor of metastasis1 and therefore as a potential biomarker to determine the need for adjuvant radiotherapy in high-risk patients.2 However, all this work has been based on retrospective data and the authors of this study report on the first prospective randomized trial of the Decipher GC in this study population.

The Genomics in Michigan ImpactiNg Observation or Radiation  (G-MINOR (NCT02783950), is an ongoing trial and is done accruing patients but final data is still pending. The authors report on patient characteristics and risk distribution of the cohort in this abstract.

In terms of study design, G-MINOR enrolled 350 participants across 12 sites (MUSIC collaborative). Eligible patients had undergone RP within 9 months of enrollment, had pT3-4 and/or positive surgical margins, and a post-RP PSA <0.1ng/mL. Hence, they were considered high-risk localized PCa patients who would normally be considered for adjuvant radiotherapy. Patients were randomized to either the GC + CAPRA-S or CAPRA-S alone. Patients in both arms received a CAPRA-S derived predicted risk of recurrence. If enrolled during the GC period, the subject and physician were also provided with the Decipher score based on RP specimens. Decipher results were assessed centrally in UC patients but were not available to clinicians or patients. Clinical data, including CAPRA-S and Decipher scores, were compared between arms in this abstract.

The full study scheme is below:

Figure 1

As of this time, 356 patients from the MUSIC collaborative met the inclusion criteria and whose RP tissue passed the required QC thresholds. Of these patients, 183 (51.4%) and 173 (48.6%) were randomized to the GC and control groups, respectively. Between study arms, the authors found no statistically significant difference in the frequency of any specific adverse pathologic features, including extraprostatic extensions, seminal vesicle invasion, or surgical margins. CAPRA-S and Decipher score distributions were also similar between the 2 groups. Full comparison between the 2 cohorts (to-date) is below:

Figure 2

However, no outcome data is available as of yet, as this study is still maturing. While fully accrued, analysis of primary data is due at 1 year. Long-term outcomes will inform biomarker and nomogram performance.

Presented By: Todd Morgan, MD, Associate Professor at the University of Michigan

Written by: Thenappan Chandrasekar, MD, Clinical Instructor, Thomas Jefferson University, @tchandra_uromd, @TjuUrology, at the 19th Annual Meeting of the Society of Urologic Oncology (SUO), November 28-30, 2018 – Phoenix, Arizona

References:
  1. Spratt DE, Yousefi K, Deheshi S, Ross AE, et al. Individual Patient-Level Meta-Analysis of the Performance of the Decipher Genomic Classifier in High-Risk Men After Prostatectomy to Predict Development of Metastatic Disease. J Clin Oncol. 2017 Jun 20;35(18):1991-1998. doi: 10.1200/JCO.2016.70.2811. Epub 2017 Mar 30. Review.
  2. Den RB, Yousefi K, Trabulsi EJ, et al. Genomic classifier identifies men with adverse pathology after radical prostatectomy who benefit from adjuvant radiation therapy. J Clin Oncol. 2015 Mar 10;33(8):944-51. doi: 10.1200/JCO.2014.59.0026. Epub 2015 Feb 9. Erratum in: J Clin Oncol. 2015 Apr 20;33(12):1416.
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