A new blood test can help predict the survival of patients with advanced prostate cancer, according to research published by Duke Cancer Institute members Andrew Armstrong, MD, and Susan Halabi, PhD. This research and study, done in collaboration with researchers at the University of Minnesota Medical School, was recently in Nature Communications.
The blood test, called AR-ctDETECT, is a comprehensive liquid biopsy assay that focuses primarily on 69 genes relevant to prostate cancer and hormone resistance, such as the androgen receptor. AR-ctDETECT measures small fragments of circulating tumor-derived DNA (ctDNA) to identify mutations and gains or losses of these genes in the blood of metastatic prostate cancer patients.
Throughout the phase 3 clinical trial involving nearly 800 men with metastatic prostate cancer who were treated with new forms of hormonal therapies such as enzalutamide or abiraterone as outlined in the publication, ctDNA was detectable in 59 percent of participants. The study also found those with detectable ctDNA had significantly worse overall survival compared to patients without detectable ctDNA. This is the largest study ever done to test the value of a liquid biopsy test in patients with prostate cancer, Armstrong said.
“This assay has aspects not available in commonly available liquid biopsy tests such as the ability to detect androgen receptor genetic rearrangements and other important alterations,” he said. “This test can inform how we might manage patients differently – if a patient has a poor prognosis, providers might do something differently, such as administer chemotherapy, radioligand therapy, or other therapies or combine therapies with other drugs.”
Being able to detect this genetic information in patients could help providers better understand a particular patient’s cancer and predict disease progression. Ultimately, this assay could help providers tailor treatment to individual patient profiles, leading to better outcomes for patients and more well-informed clinical trials in the future.
Further research seeks to integrate genetic data from the AR-ctDETECT assay with clinical data to improve prognoses. The team is developing a clinical model to help understand resistance and identify more predictive biomarkers.
“Detecting ctDNA provides a valuable tool in monitoring patients,” Halabi said. “We’re hoping this will help treatment by looking at changes in mutations and identifying actionable mutations or resistance markers and combining this with clinical features to better predict future outcomes.”