Simple Biomarker Test Could Help Guide Prostate Biopsy Decisions

This study was published on researchsquare.com as a preprint and has not yet been peer reviewed.

Key Takeaway

• A MyProstateScore result of 15 or less rules out Grade Group 2 or higher (GG ≥ 2) prostate cancer in men who have had a previous negative biopsy. The risk becomes 6.5% with scores of 15-40, and 19% for scores over 40.

Why This Matters

• Prostate cancer risk stratification is challenging in men who have had a previous negative biopsy.

• The diagnostic value of prostate-specific antigen (PSA) is limited because most men had an initial biopsy because of a PSA elevation.

• The investigators previously showed that in biopsy-naive men, MyProstateScore (LynxDx) can rule out GG ≥ 2 cancer with a 98% negative predictive value and 97% sensitivity.

• The new study validates the test’s use in men with a previous negative biopsy, adding confidence to the decision of whether to be biopsied again. 

Study Design

• The team compared MyProstateScores — a test that combines urinary expression of prostate cancer antigen 3 and the TMPRSS2:ERG gene fusion with serum PSA to define the risk of GG ≥ 2 cancer — to actual biopsy results in 268 men who had a previously negative biopsy.

• Men were a median of 64 years and had a median PSA 7.6 ng/ml.

• Urine was collected after digital rectal exam.

• Overall, 25 men (9.3%) had GG ≥ 2 cancer on repeat biopsy.

Key Results

• A MyProstateScore of 15 or below had a 100% negative predictive value and sensitivity for GG ≥ 2 cancer and would have prevented 23% of unnecessary biopsies.

• A score above 40 had a 19% risk of GG ≥ 2 disease.

• A score of 15 to 40 had a 6.5% risk of GG ≥ 2 disease.

• Together, the data suggest that men with a MyProstateScore of 15 or below can “confidently forego biopsy,” that most men with scores of 15-40 “are unlikely to benefit from repeat biopsy,” and a score greater than 40 “supports proceeding to repeat biopsy.”

Limitations

• The data do not capture PSA kinetics or the specific indications for repeat biopsy.

• Prostate biopsies can under-detect GG ≥ 2 cancer.

Disclosures

• The work was funded by the Prostate Cancer Foundation and the National Cancer Institute.

• The lead and senior investigators have equity interest in LynxDx. Another investigator is a paid consultant to the company, and a fourth is a co-inventor on and receives royalties from a patent involving the technology licensed to LynxDx.

This is a summary of a preprint research study, “MyProstateScore in Men Considering Repeat Biopsy: Validation of a Simple Testing Approach,” led by Jeffrey Tosoian, MD, MPH, Vanderbilt University Medical Center, Nashville, Tennessee. The study has not been peer reviewed. The full text can be found at researchsquare.com.

M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who has worked for several major news outlets before joining Medscape and also an MIT Knight Science Journalism fellow. Email: [email protected].

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