A new international study shows that a blood test can predict how patients with advanced prostate cancer will respond to specific treatments.
This can lead to improved prostate cancer survival.
In the study, the team recruited 142 patients with advanced prostate cancer from the London Regional Cancer Program at London Health Sciences Centre (LHSC) in London, Ontario; Memorial Sloan Kettering Cancer Center in New York; and the Royal Marsden in London, England.
The patients had already undergone at least one round of hormone-targeting therapy without success and were working with their oncologist to decide whether to switch to a different hormone-targeting therapy or to chemotherapy as their next line of treatment.
The researchers used a liquid biopsy test that examines circulating tumour cells (CTCs) in blood samples from these patients.
The blood test is developed by molecular diagnostics company Epic Sciences.
CTCs are cancer cells that leave a tumor, enter the blood stream and invade other parts of the body, causing the spread of cancer.
The test identifies whether or not a patient’s CTCs contain a protein called AR-V7 in the cell’s nucleus.
The research team found that patients who tested positive for the protein responded best to taxane-based chemotherapy.
And those who tested negative for the protein responded best to hormone-targeting therapy with drugs called androgen-receptor signaling (ARS) inhibitors.
These are the two most widely used drug classes to treat advanced prostate cancer.
This study looked at predicting the best treatment for patients who had already undergone at least one round of hormone-targeting therapy.
A future goal of the team is to assess the use of this test or similar CTC blood tests in determining optimal therapy at earlier decision points in advanced prostate cancer care.
They also plan to collaborate further with Epic Sciences to evaluate different versions of the CTC blood test for other types of cancer, such as lung cancer.
Through Epic Sciences’ partnership with Genomic Health, the CTC blood test is now commercially available in the United States as the Oncotype DX AR-V7 Nucleus Detect.
The study is an international collaborative study between Lawson Health Research Institute, Memorial Sloan Kettering Cancer Center, the Royal Marsden and Epic Sciences.
Dr. Alison Allan, a scientist at Lawson and Chair, Department of Anatomy & Cell Biology at Western University’s Schulich School of Medicine & Dentistry, is one researcher of the study.
The study is published in JAMA Oncology.
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Figure legend: This Knowridge.com image is credited to Lawson Health Research Institute.
Journal reference: Howard I. Scher et al, Assessment of the Validity of Nuclear-Localized Androgen Receptor Splice Variant 7 in Circulating Tumor Cells as a Predictive Biomarker for Castration-Resistant Prostate Cancer, JAMA Oncology (2018). DOI: 10.1001/jamaoncol.2018.1621
