PCa test predicts aggressiveness, influences treatment

The Decipher Prostate Cancer Classifier test predicts disease aggressiveness, influences treatment decisions, and predicts which patients may benefit from post-prostatectomy radiation therapy, according to findings from three studies presented at the American Society for Radiation Oncology annual meeting in San Francisco.

The presentations came on the heels of a study published in the International Journal of Radiation Oncology • Biology • Physics (2014; 89:1038:46) that showed that patients with a high Decipher score who received RT soon after surgery had improved survival times compared to those who did not, according to a press release from GenomeDx Biosciences, which makes the Decipher test. The investigators also found that patients treated with post-surgery RT maintained low PSA levels for twice as long as others.

In the first ASTRO study, Daniel Trifiletti, MD, of University of Virginia Health System, Charlottesville, and co-authors evaluated in a decision modeling study the comparative effectiveness of adjuvant versus salvage RT when Decipher as an individualized estimate of disease aggressiveness was implemented into clinical patient care. The results showed that treatment decisions involving the Decipher test led to an increase in adjuvant RT utilization, and, overall, resulted in an increase in life years and quality-adjusted life years for those patients.

The second study, led by Paul Nguyen, MD, of Harvard Medical School, Boston, found that Decipher test results led to an increase in agreement in treatment recommendations among 26 radiation oncologists and 20 urologists. Using clinical information alone, observation was recommended in 42% of decisions made by urologists and 23% by radiation oncologists. When the same cases were randomized and reviewed again with Decipher test results, treatment recommendations changed by 45% and 35% of each group, respectively.

In the third study, which included 188 patients from Thomas Jefferson University, Philadelphia, and Mayo Clinic, Rochester, MN, 71 patients with average and high-risk CAPRA-S scores were reclassified as low risk based on Decipher test results. Additionally, for Decipher high-risk patients, a significant difference (17%) in metastasis was observed at 5 years for the adjuvant (6%) compared to salvage (23%) arm (p=.008), indicating that Decipher high-risk men may benefit from adjuvant RT after surgery.

“The genomic classifier used in this study was able to classify patients at high risk of metastasis and predict patients most likely to benefit from adjuvant radiation therapy more accurately than the clinical tools we use today. Integration of genomic test results into clinical practice can often give physicians additional insight into the aggressiveness of cancer and increase confidence in the selection of therapy,” said Robert Den, MD, of Thomas Jefferson University.