Multiparametric magnetic resonance and Prostate Cancer

‘Strong Argument’ For MP-MRI Triage In High PSA Level Men
Multiparametric magnetic resonance imaging could improve detection of clinically significant prostate cancer and avoid clinically insignificant diagnoses

Date: 23 Jan 2017
Author: By Lynda Williams, Senior medwireNews Reporter
Topic: Prostate Cancer / Imaging, Diagnosis and Staging

medwireNews: PROMIS trial findings support the use of multiparametric magnetic resonance imaging (MP-MRI) for men with high levels of serum prostate-specific Antigen (PSA).

“Using MP-MRI as a triage test would reduce the problem of unnecessary biopsies in men who have a low risk of harbouring clinically significant cancer, reduce the diagnosis of clinically insignificant disease and improve the detection of clinically significant cancers”, say Hashim Ahmed, from University College London in the UK, and co-investigators.

The PROMIS study reports on findings for men with a PSA of up to 15 ng/mL who underwent MP-MRI followed by both transrectal ultrasound (TRUS)-guided biopsy (10–12 cores), and the reference test template prostate mapping (TPM)-biopsy (cores removed every 5 mm).

TPM-biopsy identified prostate cancer in 71% of 576 men, of whom 40% had clinically significant disease, defined as a Gleason score of 4+3 or higher, or a maximum cancer core length of at least 6 mm.

MP-MRI was significantly more sensitive at detecting clinically significant prostate cancer than TRUS-guided biopsy (93 vs 48%), albeit with significantly poorer specificity (41 vs 96%).

In addition, MP-MRI had a significantly better negative predictive value than TRUS-guided biopsy (89 vs 74%) and significantly lower positive predictive value (51 vs 90%).

“Using MP-MRI to triage men might allow 27% of patients [to] avoid a primary biopsy”, the researchers explain, as well as “diagnosis of 5% fewer clinically insignificant cancers”.

They continue: “If subsequent TRUS-biopsies were directed by MP-MRI findings, up to 18% more cases of clinically significant cancer might be detected compared with the standard pathway of TRUS-biopsy for all.”

Hashim Ahmed et al conclude: “Cost-effectiveness analyses of the PROMIS data are underway and will be reported elsewhere, but the primary outcome data provide a strong argument for recommending MP-MRI to all men with an elevated serum PSA before biopsy.”

Reference

Ahmed HU, El-Shater Bosaily A, Brown LC, et al. Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): a paired validating confirmatory study. Lancet; Advance online publication 19 January 2017. DOI: http://dx.doi.org/10.1016/S0140-6736(16)32401-1