Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): a paired validating confirmatory study

BACKGROUND: Men with high serum prostate specific antigen usually undergo transrectal ultrasound-guided prostate biopsy(TRUS-biopsy).  TRUS-biopsy can cause side-effects including bleeding, pain, and infection.  Multi-parametric magnetic resonance imaging (MP-MRI) used as a triage test might allow men to avoid unnecessary TRUS-biopsy and improve diagnostic accuracy.

METHODS: We did this multicentre, paired-cohort, confirmatory study to test diagnostic accuracy of MP-MRI and TRUS-biopsy against a reference test (template prostate mapping biopsy [TPM-biopsy]).  Men with prostate-specific antigen concentrations up to 15 ng/mL, with no previous biopsy, underwent 1·5 Tesla MP-MRI followed by both TRUS-biopsy and TPM-biopsy.  The conduct and reporting of each test was done blind to other test results.  Clinically significant cancer was defined as Gleason score ≥4 + 3 or a maximum cancer core length 6 mm or longer.  This study is registered on ClinicalTrials.gov, NCT01292291.

RESULTS: Between May 17, 2012, and November 9, 2015, we enrolled 740 men, 576 of whom underwent 1·5 Tesla MP-MRI followed by both TRUS-biopsy and TPM-biopsy. On TPM-biopsy, 408 (71%) of 576 men had cancer with 230 (40%) of 576 patients clinically significant.  For clinically significant cancer, MP-MRI was more sensitive (93%, 95% CI 88-96%) than TRUS-biopsy (48%, 42-55%; p<0·0001) and less specific (41%, 36-46% for MP-MRI vs 96%, 94-98% for TRUS-biopsy; p<0·0001).  44 (5·9%) of 740 patients reported serious adverse events, including 8 cases of sepsis.

CONCLUSION: Using MP-MRI to triage men might allow 27% of patients avoid a primary biopsy and diagnosis of 5% fewer clinically insignificant cancers.  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.  MP-MRI, used as a triage test before first prostate biopsy, could reduce unnecessary biopsies by a quarter.  MP-MRI can also reduce over-diagnosis of clinically insignificant prostate cancer and improve detection of clinically significant cancer.

Lancet. 2017 Feb 25;389(10071):815-822. doi: 10.1016/S0140-6736(16)32401-1. Epub 2017 Jan 20.

Ahmed HU1, El-Shater Bosaily A2, Brown LC3, Gabe R4, Kaplan R3, Parmar MK3, Collaco-Moraes Y3, Ward K3, Hindley RG5, Freeman A6, Kirkham AP7, Oldroyd R8, Parker C9, Emberton M2; PROMIS study group.
 
Author information:
Division of Surgery and Interventional Science, Faculty of Medical Sciences, University College London, London, UK; Department of Urology, UCLH NHS Foundation Trust, London, UK. 
Division of Surgery and Interventional Science, Faculty of Medical Sciences, University College London, London, UK; Department of Urology, UCLH NHS Foundation Trust, London, UK.
MRC Clinical Trials Unit at UCL, London, UK.
Hull York Medical School and Department of Health Sciences, University of York, UK.
Department of Urology, Hampshire Hospitals NHS Foundation Trust, UK.
Department of Histopathology, UCLH NHS Foundation Trust, London, UK.
Department of Radiology, UCLH NHS Foundation Trust, London, UK.
Public and patient representative, Nottingham, UK.
Department of Academic Urology, Royal Marsden Hospital, Sutton, UK.