Urine Testing for Prostate Cancer Screening: Outcomes Data from a Massachusetts Suburban Community Setting for the DLX1/HOXC6 mRNA Urine Test
Michael Geffin, MD
Greater Boston Urology, Dedham, MA
Urine Testing for Prostate Cancer Screening: Outcomes Data from a Massachusetts Suburban Community Setting for the DLX1/HOXC6 mRNA Urine Test.
Introduction and Objectives
For years prostate cancer (PCa) screening has been criticized for its inaccuracy resulting in over biopsy. Newer commercially available urine and blood tests have been approved that further quantify patients as low or high risk for having the disease. Urinary DLX1 and HOXC6 mRNA are highly express in the setting of prostate cancer and have been shown to be predictive of higher grade PCa1. The validation population for this test from the Netherlands reported a 98% negative predictive value. We looked at patients who were tested with the commercially available DLX1/HOXC6 mRNA urine test2 and then subsequently underwent standard prostate biopsy to assess accuracy of this tests screening results in the Massachusetts community setting.
Methods
This is a retrospective study of 271 patients from April 2016 to March 2018 from a single large practice urology group who had the DLX1/HOXC6 mRNA urine test. All patients that were tested with the DLX1/HOXC6 mRNA urine test and subsequently underwent transrectal ultrasound guided prostate biopsy for suspicion of prostate cancer were included in this analysis. Patients were grouped according to urine test results, Very Low Risk (VLR) group and Higher Risk Group (i.e. any report that was not VLR). The groups were assessed for differences in age at biopsy, PSA, prostate size, PSA density, PHI, and PHI density. Analyses of the urine test for sensitivity, specificity, positive predictive value and negative predictive value were undertaken for both biopsy results of PCa and significant PCa.
Results
Of 271 patients, 59 underwent prostate biopsy. Of the 59 biopsied patients, there were 18 patients in the VLR Group and 41 patients in the Higher Risk Group. There were no statistical differences between the groups in prostate size (61.0g vs. 70.7g, p=0.34), PSA density (0.10 vs. 0.17), PHI (33.9 vs. 45.4), or PHI density (0.55 vs. 1.06). There were statistical differences in age at biopsy (64.0 vs. 69.5, p=0.0098) and PSA (5.52 vs. 9.01, p=0.0008). In diagnosing PCa, we found a sensitivity of 74.2%, specificity of 35.7%, positive predictive value of 56.1%, and a negative predictive value of 55.6%. In diagnosing significant PCa, we found a sensitivity of 79.2%, specificity of 37.1%, positive predictive value of 46.3% and a negative predictive value of 72.2%.
Conclusions
These results of DLX1/HOXC6 mRNA urine testing in the community setting are in line with other commercially available prostate cancer screening tests in regards to sensitivity, specificity, positive predictive value and negative predictive value. This was a small cohort and further studies with larger cohorts should be undertaken.
1-Van Neste L, Hendriks R, Dijkstra S, et al. Detection of High-grade Prostate Cancer Using a Urinary Molecular Biomarker-Based Risk Score. Eur Urol 2016;70:740-748
2-SelectMDx urine test, MDxHealth Irvine, CA
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