Using multiparametric magnetic resonance imaging (mpMRI) to triage men with high serum PSA could save 27% of patients from having transrectal ultrasound-guided prostate biopsy (TRUS biopsy), according to a new study published online in The Lancet (Jan. 19, 2017).
Doing the scan prior to biopsy could also improve the diagnosis, reducing the detection of clinically insignificant cancers by 5%, while improving detection of clinically significant disease, the authors wrote.
“We must seriously consider changing our practice across all health care settings to institute an imaging test—multiparametric MRI, in this instance—before a biopsy test, which is random. It is what we do for all other solid organ cancers, and we now have robust evidence for a similar diagnostic pathway in prostate cancer,” said lead author Hashim U. Ahmed, PhD, BM, BCh, of Imperial College, London.
The study helps to create a level of evidence that was lacking in the use of mpMRI in diagnosing prostate cancer. Many papers were retrospective; many compared mpMRI to surgical specimens, which meant that all men had to have cancer on biopsy and then choose surgery. Still others compared mpMRI to TRUS-biopsy, which is known to be inaccurate, and many studies were based in centers of excellence, according to Dr. Ahmed.
“As a result of these methodological biases, there was considerable uncertainty and skepticism about the performance of mpMRI,” Dr. Ahmed said.
In this study, 576 men with PSA concentrations up to 15 ng/mL and no prior biopsies were given an mpMRI. The mpMRI looks at tissue anatomy, as well as prostate volume, cellularity, and vascularity. There is evidence that this scan type is likely to detect higher risk disease and overlook low-risk disease, according to the study.
Patients in the multicenter study also received a TRUS biopsy and template prostate mapping biopsy as a reference test.
The authors defined clinically significant prostate cancer as having a Gleason score of ≥4+3 or a cancer core length of 6 mm or longer of any grade.