Comparison of bi- and multiparametric magnetic resonance imaging to select men for active surveillance

Abstract

BACKGROUND: Active surveillance of men with prostate cancer relies on accurate risk assessments because it aims to avoid or delay invasive therapies and reduce overtreatment. PURPOSE: To compare the diagnostic performance of pre-biopsy biparametric magnetic resonance imaging (MRI) with confirmatory multiparametric MRI in selecting men for active surveillance. MATERIAL AND METHODS: The study population included biopsy-naïve men with clinical suspicion of prostate cancer undergoing biparametric MRI followed by combined (standard plus MRI targeted) biopsies. Men diagnosed with prostate cancer who were subsequently enrolled in active surveillance and underwent a confirmatory multiparametric MRI within three months of diagnosis were included in the study. Discrepancies between the pre-biopsy biparametric MRI and the confirmatory multiparametric MRI were assessed. RESULTS: Overall, 101 men (median age = 64 years; median prostate-specific-antigen level = 6.3 ng/mL) were included. Nine patients were re-biopsied after multiparametric MRI for the following reasons: suspicion of targeting error (three patients); a new suspicious lesion detected by multiparametric MRI (five patients); and an increase in tumor volume (one patient) compared with biparametric MRI. Confirmatory biopsies showed a Gleason grade group (GG) upgrade of ≥2 in 4/6 patients with suspicion of more advanced disease (missed suspicious lesion, increase in tumor volume) on multiparametric MRI. However, although multiparametric MRI subsequently detected a GG ≥ 2 prostate cancer lesion missed by biparametric MRI in 4% (4/101) of included men, the difference did not reach statistical significance (McNemar, P = 0.133). CONCLUSION: Biparametric MRI could be used to select men eligible for active surveillance and a confirmatory multiparametric MRI performed shortly after inclusion seems unnecessary.