Predicting Metastatic Disease After Radical Prostatectomy
An individual patient-level meta-analysis has shown that the Decipher® (GenomeDx) genomic classifier is capable of distinguishing risk groups for metastatic disease after radical prostatectomy for prostate cancer. The study was reported by Spratt and colleagues in the Journal of Clinical Oncology.
Study Details
The analysis included 5 studies published between 2011 and 2016 that assessed performance of the Decipher test. Of the total of 975 patients, 855 had available individual patient-level data. Multivariable Cox proportional hazards models fit to individual patient data were performed; meta-analyses were performed by pooling the study-specific hazard ratios (HRs) using random-effects modeling. Decipher provides a continuous score between 0 and 1, with higher scores indicating a greater risk of metastasis. Cutpoints of 0.45 and 0.60 are used to categorize patients into low-, intermediate-, and high-risk groups.
Test Performance
Median follow-up for all patients was 8 years. In the cohort of 855 patients, 60.9%, 22.6%, and 16.5% of patients were classified by Decipher as low, intermediate, and high risk, respectively. The 5-year cumulative rates of metastases were 2.4%, 5.8%, and 15.2% in these risk groups, and the 10-year cumulative rates were 5.5%, 15.0%, and 26.7% (P < .001). Pooling of the study-specific hazard ratios across the 975 patients in the 5 studies resulted in a hazard ratio of 1.52 per 0.1 Decipher unit increase (95% confidence interval [CI] =1.39–1.67; I2 test for heterogeneity = 0%).
On multivariable analysis of individual patient data including preoperative prostate-specific antigen level, radical prostatectomy Gleason score, margin status, extracapsular extension, seminal vesical invasion, and lymph node invasion, Decipher remained a significant predictor of metastasis (HR = 1.30, P < .001, per 0.1 unit). The C-index for 10-year distant metastasis was 0.76 for the clinical model alone and increased to 0.81 when Decipher was included.
The investigators concluded: “The genomic classifier test, Decipher, can independently improve prognostication of patients post-prostatectomy, as well as within nearly all clinicopathologic, demographic, and treatment subgroups. Future study of how to best incorporate genomic testing in clinical decision-making and subsequent treatment recommendations is warranted.”
The study was funded by the Prostate Cancer Foundation Young Investigator Award.
Felix Y. Feng, MD, of the University of California San Francisco Helen Diller Family Comprehensive Cancer Center, is the corresponding author of the Journal of Clinical Oncology article.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
