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Biomarkers May Improve Prostate Cancer Screening
Five studies evaluating the use of imaging and urine-based biomarkers as ways to improve prostate cancer detection were presented during the 110th Annual Scientific Meeting of the American Urological Association in New Orleans.
The studies examine ways to diagnose or risk-stratify prostate cancer in patients through multi-parametric magnetic resonance imaging (mpMRI) or urine testing by:
- Diagnosing clinically meaningful, higher-grade cancers with fewer biopsies.
- Using gene detection in combination with risk scores to better detect prostate cancer compared to standard screening.
- Utilizing strategies to minimize the number of men requiring biopsy.
- Using mpMRI to distinguish between clinically significant and insignificant cancers.
- Minimizing the need for biopsies by analyzing genes in the urine.
In one study, “Validated Urine-Based Multigene Signature for Detection of Aggressive Prostate Cancer,” Canadian researchers examined urine samples obtained after digital rectal examinations (DREs) from 764 men (261 men in the discovery arm and 503 men in the validation arm) with elevated PSAs. The researchers identified genes associated with aggressive cancers, developed a Prostate Cancer Panel (PCP) Risk Score using the discovery arm, and validated this panel with the second group. Prostate cancer was identified in 42% of the discovery arm and 49% of the validation arm. After controlling for established risk factors (age, abnormal DRE, or prior biopsy history), researchers found the PCP Risk Score was independently associated with the detection of high-grade cancer at biopsy. Men with a PCP Risk Score greater than 60 had a 74% risk of high-grade prostate cancer. Men with a score less than 20 had only a 7% risk of high-grade disease.
In a second study, “MR-US Fusion Biopsy to Diagnose Prostate Cancer: First 1000 Men at UCLA,” researchers at the University of California, Los Angeles (UCLA) evaluated the first 1,000 men who underwent mpMRI and MR-ultrasound (MR-US) fusion prostate biopsy between 2009 and 2014. Among those who had MR-US, an increased risk of finding prostate cancer was directly related to age, MRI findings, PSA, and PSA density. The most powerful predictor was the MRI; high-risk prostate cancer was found in most men with highly suspicious (grade 5) MRI lesions. Both mapping and targeted biopsy were required for maximum detection of high-grade prostate cancers.
A third study, “Comparison of MRI-US Fusion Targeted Biopsy and Systematic Prostate Biopsy: Single Institution Experience in 604 Patients,” found that MRI fusion targeted biopsy (MRF-TB) detects more high-grade prostate cancer (Gleason score greater than or equal to 7) and less Gleason 6 cancers than a systematic 12-core biopsy. The research from New York University and New York Hospital in Queens, New York, based on 604 men undergoing mpMRI prior to prostate biopsy since June 2012, suggests this biopsy technique may be more effective in helping to reduce over-detection of lower risk tumors.
The fourth study, “Combining Urine PCA3 and TMPRSS2:ERG Tests to Refine Prostate Cancer Detection — Validation Study and Health Economic Analysis,” found that when used together, these two urine assays may effectively identify men with high-risk prostate cancer, minimizing unnecessary biopsy in men between 55 and 64 with lower-risk disease. Used together, the tests can avoid unnecessary biopsies in nearly half (49%) of the men, improve specificity in identifying aggressive prostate cancer, and reduce costs.
And in the fifth study — “Should a Normal Multi-Parametric MRI Preclude Prostate Biopsy?” — UCLA researchers say men with an elevated PSA level should consider a prostate biopsy even if a mpMRI appears normal. Examining data from 244 men who underwent mpMRI and ultrasound-guided biopsy between 2009 and 2014, researchers found mpMRI failed to identify 16% of men with high-grade cancer (Gleason score greater than or equal to 7), while 47% of patients with no “region of interest” on mpMRI were found to have a Gleason score equal to or greater than 6 on their biopsies.
Source: American Urological Association; May 18, 2015