Epigenetic Test eliminates unnecessary repeat prostate biopsies -
Over one million prostate biopsies are performed annually in the US alone, there including many repeat biopsies for fear of missed cancer. Therefore, it is necessary to develop diagnostic tests that will help avoid unnecessary repeat biopsies. Two independent tests have validated the performance of an epigenetic test could give doctors a better tool to help eliminate unnecessary repeat prostate biopsy, investigators report in The Journal of Urology- .
In independent MATLOC previously (methylation analysis to locate the Occult cancer) test, an epigenetic multiplex assay (ConfirmMDx for prostate cancer) APC profile, the GSTP1 gene and RASSF1 demonstrated value 0% negative predictive. GSTP1 methylation is a specific biomarker (prostate), cancer and the gene is methylated in 0% of cases of prostate cancer. Furthermore, APC and RASSF1 are important field effect markers and increase the diagnostic sensitivity of the test.
A second multicenter, DOCUMENT (Cancer Detection Using events methylated in the negative tissue), validated the performance of epigenetics test used in MATLOC test as an independent predictor of cancer risk prostate to guide decision making for repeat biopsy. Patients in the study of materials with a negative biopsy were evaluated to identify people at low risk of harboring the cancer missed due to biopsy sampling error, which could give an unnecessary biopsy repetition. The validation study yielded a negative predictive value of 88%.
"This epigenetic test is an important, independent predictor and has been shown to be a most valuable diagnostic aid for all risk factors assessed in two independent trials," commented Alan W. Partin, MD, PhD , James Buchanan Brady Urological Institute, the school of medicine at Johns Hopkins University, Baltimore, Md. "the negative results of this test could be used to reduce concerns about the unsampled cancer effectively and avoid unnecessary repeat biopsies . "
A total of 350 patients were enrolled in the document process from five medical centers geographically dispersed: Cleveland Clinic, school Eastern Virginia medical Lahey Hospital & medical Center, Johns Hopkins University, and the University of California at Los Angeles. patients were grouped into those with two consecutive negative biopsies (controls) and those with a negative biopsy followed by a positive biopsy within 24 months. Initial archived negative for cancer, prostate biopsy tissue samples were evaluated. All men underwent repeat biopsy on average one year after the initial biopsy.
Only biopsies with a minimum of eight cores per biopsy, gathered early 07, were included in the study, while initial biopsies with atypical cells suspicious for cancer, namely small acinar proliferation atypical by pathologists sites were excluded, as this would have triggered a repeat biopsy based on single histopathology.
After adjusting for age, prostate specific antigen (PSA), digital rectal examination, histopathological characteristics of the first biopsy, and race, this epigenetic test proved to be the most important independent predictor and the strongest of patient outcomes with an odds ratio of 2.69 and a diagnostic aid the most precious of all risk factors evaluated. The slight decrease in sensitivity of the test DOCUMENT compared to MATLOC test is most likely associated with a higher prevalence of PSA screening in the cohort DOCUMENT.
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