Background: Early detection of significant prostate cancer (PCa) increases the curative success rate. The 2-gene mRNA PCR urine test (SelectMDx™) is based on a biomarker expression profile combined with traditional clinical risk factors resulting in a likelihood risk score to detect clinically significant PCa (Gleason score (GS) ≥7) upon biopsy. The results of the SelectMDx test was compared to the ERSPC risk calculator in a cohort of Dutch men.
Methods: A total of 60 men, 26 men biopsy-naïve, and 34 with a history of one or more previous negative biopsies. All men, enrolled in a peripheral hospital, were tested with the ERSPC risk calculator taking into consideration serum PSA, biopsy history, DRE outcome, TRUS outcome and prostate volume. In addition, the first voided urine after a DRE was collected and used for the SelectMDx test. 25 out of 60 men (42%) underwent a prostate biopsy, diagnosing 10 men with PCa. Follow-up of the 35 men was done by serum PSA and/or MRI (24% underwent MRI and were cT0).
Results: In 26 biopsy-naïve men, both the ERSPC risk Calculator as well as the SelectMDx test indicated the need for biopsy in 11 men (Table 1). In total, 14 men underwent prostate biopsies (54%) of which 5 were found to have PCa (one unknown GS, one GS 6 and three GS ≥7). The ERSPC risk calculator indicated no need for biopsy in 9 men (38%). The SelectMDx test was very low risk for high grade PCa in 14 men (53%), resulting in a no biopsy decision for 42% of the men.
Of the 34 men with a prior negative biopsy, both the ERSPC risk calculator as well as the SelectMDx test indicated the need for prostate biopsy in 5 men (Table 2) and high grade PCa was detected in 2 of the 3 men that underwent biopsies. The ERSPC risk calculator was negative in 85% of men. However, the SelectMDx test indicated a risk for finding high grade PCa upon biopsy in 15 ERSPC risk calculator negative men. Biopsy was done in 6 of the 15 men, confirming PCa in 3 men by histopathology (one GS 6 and two GS 7). In this cohort, 68% of men did not undergo a repeat biopsy.
Conclusion: This is the first clinical study on the use of SelectMDx in Dutch cohort. Compared to the ERSPC risk calculator, the systematic use of the SelectMDx test led to a significant reduction of biopsies in biopsy-naïve men and improved the detection rate of significant PCa in men with prior negative biopsies. These results suggest that SelectMDx testing leads to improvement in diagnosis and management of PCa patients. Additional studies are required due to the limited number of patients and the lack of long-term follow-up of the no-biopsy cases.
Table 1: Concordance table SelectMDx versus ERSPC risk calculator for predicting high grade PCa upon biopsy in biopsy-naïve men
|
ERSPC risk calculator +
|
ERSPC risk calculator -
|
total
|
SelectMDx +
|
11
|
1
|
12
|
SelectMDx -
|
5
|
9
|
14
|
total
|
16
|
10
|
26
|
Table 2: Concordance table SelectMDx versus ERSPC risk calculator for predicting high grade PCa upon biopsy in a previous negative biopsy cohort
|
ERSPC risk calculator +
|
ERSPC risk calculator -
|
total
|
SelectMDx +
|
5
|
15
|
20
|
SelectMDx -
|
0
|
14
|
14
|
total
|
5
|
29
|
34
|