Overall, the wide range of GPS scores documented across the 175 patients suggested that the unfavorable, intermediate-risk group is not a homogenous one, the authors noted.
“It was a welcome finding to see that the GPS could be useful in this additional subset of men,” Dr Cullen noted, adding that the findings support the current ASCO recommendations that say the assay may be considered in select patients with unfavorable, intermediate-risk disease. However, “we definitely need additional studies,” she added.
“There are a number of genomic and/or transcriptomic tools that are emerging for use and helping us more intelligently guide efforts to intensify treatment or potentially to de-escalate treatment in particular patients so that we’re not treating everybody with a kitchen-sink approach . . . This study adds to that literature,” noted Amar U. Kishan, MD, vice chair of clinical and translational research of the department of radiation oncology at the David Geffen School of Medicine at the University of California, Los Angeles, who wasn’t involved in the new research.
One limitation of the study, however, is that all patients were treated with surgery, “so seeing how this extrapolates to patients [who] are treated with radiation, with or without hormone therapy, is unclear because that’s a different mechanism of treating cancer,” he noted. In addition, as acknowledged by the authors, the patients were not initially classified as having favorable or unfavorable intermediate-risk disease, as they were treated at a time when that stratification scheme did not yet exist. Perhaps the patients would have been treated differently today based on those classifications, Dr Kishan suggested.
In addition, although 1 of the cohorts included a relatively high proportion of patients who self-reported as African American (19%), the tool has not yet been shown to perform comparably in other ethnic and racial cohorts, Dr Cullen said.
Another recent study in the Journal of Clinical Oncology suggested that the GPS assay was not predictive in a different subset of patients who were on active surveillance and who ultimately underwent surgery.6 “I think that study needs to be replicated in other cohorts,” Dr Cullen said.
She hopes the findings could help push the tool into clinical practice to help guide treatment decisions for patients with unfavorable, intermediate-risk disease, she said. “This would build out yet another risk stratum [in which] we could say the GPS is useful for this patient subset as well.”
Disclosure: This study was funded by Genomic Health Inc., an Exact Sciences Corporation, which developed the Genomic Prostate Score assay. In addition, some of the investigators disclosed various financial ties to the pharmaceutical industry in this study. For a full list of disclosures, please refer to the original paper.
- Cullen J, Kuo H, Shan J et al. The 17-gene Genomic Prostate Score test as a predictor of outcomes in men with unfavorable intermediate risk prostate cancer [published online ahead of print June 7, 2020]. Urology. doi:10.1016/j.urology.2020.05.045
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Prostate Cancer, Version 2.2020—May 21, 2020. Accessed July 13, 2020.
- Eggener SE, Rumble RB, Armstrong AJ, et al. Molecular biomarkers in localized prostate cancer: ASCO Guideline. J Clin Oncol. 2019;38(13):1474-1494.
- Cullen J, Rosner IL, Brand TC, et al. A biopsy-based 17-gene Genomic Prostate Score predicts recurrence after radical prostatectomy and adverse surgical pathology in a racially diverse population of men with clinically low- and intermediate-risk prostate cancer. Eur Urol. 2015:68(1):123-131.
- Van Den Eeden SK, Lu R, Zhang N et al. A biopsy-based 17-gene Genomic Prostate Score as a predictor of metastases and prostate cancer death in surgically treated men with clinically localized disease. Eur Urol. 2018:73(1):129-138.
- Lin DW, Zheng Y, McKenney JK et al. 17-gene Genomic Prostate Score test results in the Canary Prostate Active Surveillance Study (PASS) cohort. J Clin Oncol. 2020:38(14):1549-1557.