GenomeDx Biosciences has announced the publication of a validation study of its Decipher Prostate Cancer Classifier, a genomic test for prostate cancer (PC) designed to improve clinical decisions regarding patient treatment and risk of metastasis following a diagnostic biopsy or radical prostatectomy (RP).
The study “Efficacy of post-operative radiation in a prostatectomy cohort adjusted for clinical and genomic risk,” was published in the journal Prostate Cancer and Prostatic Diseases.
GenomeDx’s Decipher test includes Decipher Biopsy — used after a prostate cancer diagnosis — and Decipher Post-Op, which follows prostate surgery. The two commercially available tests provide an assessment of tumor aggressiveness based on a patient’s unique genomic profile. These tests are intended to help physicians stratify their patients by cancer risk to better determine those most likely to benefit from further treatment, and those at low risk of spread.
Results from the retrospective study validated the clinical genomic risk assessment made by Decipher and CAPRA-S (Cancer of the Prostate Risk Assessment) — a score of potential prostate cancer recurrence based on pretreatment clinical data — on metastasis outcomes for patients receiving three different postoperative radiation therapies compared to observation alone.
Data found that patients with lower clinico-genomic risks, as assessed by these scores, have excellent survival rates without any postoperative therapy, and those at higher risk have the best outcomes when given adjuvant radiation therapy early.
“Treating prostate cancer patients according to a uniform strategy is inadequate, and can result in over- or under-treatment for many men,” Ashley Ross, MD, the study’s lead author and an assistant professor of urology at Johns Hopkins Medical Center, said in a press release. “This can result in exposing the patient to unnecessary toxicity, missing the opportunity to achieve cure as well as overburdening of the healthcare system. The findings of this study may provide patients and physicians with improved tools with which decisions could be made regarding further treatment, if any, after surgery.”
A total of 422 prostate cancer patients who had undergone a radical prostatectomy which showed adverse pathological features were included in the study. The surgeries took place at one of four centers between 1990 and 2010, and patients were identified using the Decipher GRID database — a resource holding the genomic profiles on thousands of patient tumors. All had healthy prostate-specific antigen (PSA) scores (undetectable levels) following surgery, and were assigned to either observation (157 patients) or radiation therapy (adjuvant radiation treatment [111 patients], minimal residual disease salvage radiotherapy , or salvage radiation therapy ), with the therapy choice determined by PSA levels. Clinical-genomic risk was also assessed by CAPRA-S and Decipher.
During a follow-up of eight years, 37 men developed metastatic prostate cancer. On multivariable analysis, the study reported, both CAPRA-S and Decipher scores were independent predictors of this outcome. The analysis also revealed that salvage radiation or no radiation therapy were associated with a roughly fivefold increase in the rates of metastasis when compared with the other therapies.
“The imprecise identification of patients at highest risk of metastatic disease and death from prostate cancer highlights the need for additional risk stratification beyond the clinical features,” said Doug Dolginow, chief executive officer of GenomeDx. “This study further supports the use of clinical and genomic information together to provide a more comprehensive assessment of metastatic risk. Further, it demonstrates how incorporation of the Decipher test into patient treatment plans allows for an individualized approach to the care of men with prostate cancer, which we believe results in improved patient quality of life and efficient use of healthcare resources.”