New Genomic Test Can Eliminate Up to One-Third of Medically Unnecessary Prostate Cancer Biopsies

Genetic testing has been shown to be effective in detecting prostate cancer and eliminating the need for unnecessary biopsies. And even though the current commercial market for such tests is crowded, it appears that a new product is about to enter. The Diagnostic Challenge Prostate cancer is the most common form of cancer in men, claiming more than 10,000 lives per year. But screening for prostate cancer is more problematic than screening for its sister diseases, breast and cervical cancer. The effectiveness of current prostate-specific antigen (PSA) blood testing is marred by the PSA protein’s lack of reliability as a biomarker. Thus, while high PSA levels denote prostate cancer, the cancer is often low grade and poses no threat to the patient. High PSA may also indicate infection, inflammation or other disease. But because of the risks involved, physicians commonly order biopsies to rule out prostate cancer for patients whose screening tests show high PSA levels. A large percentage of these biopsies ultimately prove unnecessary. The Study A new study published in the Journal of Urology (March 2021) reports that a urine test called MyProstateScore can enable physicians to avoid one-third of unnecessary prostate cancer biopsies. Developed by researchers at the University of Michigan’s Rogel Cancer Center, the MyProstateScore measures levels of cancer-specific genes. Because half of all prostate tumors contain a genetic anomaly, the genes TMPRSS2 and ERG relocate on a chromosome and fuse together, which switches on prostate cancer. The MyProstateScore assay uses serum PSA, urinary PSA 3 and urinary TMPRSS2:ERG to calculate a score determining the presence of prostate cancer. Its effectiveness in eliminating unnecessary biopsies is based on the results of a validation study performed on 1,525 patients. The researchers found that 338 of the men (22 percent) had grade group 2 or higher cancer on biopsy. Key conclusions:

• Using a MyProstateScore threshold of 10 resulted in 97 percent sensitivity and 98 percent negative predictive value for ≥ 2 cancer, meaning the test would have prevented 387 unnecessary biopsies and missed 10 grade ≥ 2 cancers; and
• Using a MyProstateScore threshold of ≤ 10 resulted in 96 percent sensitivity and 97 percent predictive value and would have prevented 32 percent of unnecessary biopsies while missing 3.7 percent of grade ≥ 2 cancers.

Takeaway The researchers have formed a start-up company called LynxDx to commercialize the MyProstateScore test. In so doing, they will be joining a crowded market dominated by Prolaris (Myriad Genetics), the Oncotype Dx Prostate Cancer Assay (Genomic Health) and the Decipher Prostate Cancer Classifier (Decipher Biosciences, slated to be acquired by Veracyte).