(UroToday.com) The Decipher classifier may be applied to prostate tumor tissue to help predict which patients undergoing prostatectomy may benefit the most from post-operative radiotherapy. To evaluate this, the G-MINOR study enrolled patients with pT3+ and/or surgical margin positive disease at the time of prostatectomy who had a subsequent PSA drop to less than 0.1. Patients were randomized to a genomic testing arm or control arm, and treatment decisions were left to the patient and provider (not mandated by trial). Decipher results were obtained on all patients, but only 1 arm of the study received this information. All patients were also counseled on their CAPRA-S score. The endpoint of this study was to determine how Decipher results impact clinical decision making for adjuvant radiotherapy versus surveillance. The study schema is shown below.
A total of 356 patients were enrolled, and 340 patients completed the required 18 months of post-RP follow-up for inclusion in the analysis. Patients were balanced amongst groups by both CAPRA-S and Decipher risk groups. Decipher scores varied considerably for each CAPRA-S risk score, as shown in the figure below. Patients that received adjuvant radiation therapy are indicated as red dots.
The main results of the study are shown below. In patients who were high-risk by Decipher score and received these results (genomic arm), the odds ratio of receiving adjuvant treatment was 7.6. For patients who were high risk by Decipher score but did not know these results, there was no statistically significant increase in risk of receiving adjuvant treatment just using counseling with CAPRA-S score. CAPRA-S score alone did have an increased risk of receiving adjuvant treatment.
Dr. Morgan concluded that this first randomized and prospective study of the impact of the Decipher classifier demonstrates that its use impacts the use of adjuvant radiotherapy after prostatectomy. Prospective quality of life and long-term oncologic outcome data will be forthcoming in the future to further assess the clinical utility of this test.
Presented by: Todd M. Morgan, M.D. is a urological surgeon specializing in the treatment of genitourinary malignancies and a Professor of Urology, the University of Michigan
Written by: Alok Tewari, MD, PhD, Medical Oncologist at the Dana-Farber Cancer Institute, during the 2021 American Society of Clinical Oncology Genitourinary Cancers Symposium (#GU21), February 11th-February 13th, 2021