Low suspicion lesions on multiparametric magnetic resonance imaging predict for the absence of high-risk prostate cancer

OBJECTIVE To determine whether multiparametric magnetic resonance imaging (mpMRI) has the potential to identify patients at low risk for cancer, thus obviating the need for biopsy. Prostate cancer is currently diagnosed by random biopsies, resulting in the discovery of multiple low-risk cancers that often lead to overtreatment. PATIENTS AND METHODS We reviewed 800 consecutive patients who underwent a 3 Tesla mpMRI of the prostate with an endorectal coil from M arch 2007 to November 2011. All suspicious lesions were independently reviewed by two radiologists using T2-weighted, diffusion-weighted, spectroscopic and dynamic contrast-enhanced MRI sequences. Patients with only low suspicion lesions (maximum of two positive parameters on mpMRI) who subsequently underwent transrectal ultrasonography (TRUS)/MRI fusion targeted biopsy were selected for analysis. RESULTS In total, 125 patients with only low suspicion prostatic lesions on mpMRI were identified. On TRUS /MRI fusion biopsy, 77 (62%) of these patients had no cancer detected, 38 patients had Gleason 6 disease and 10 patients had Gleason 7 (3 + 4) disease. There were 30 patients with cancer detected on biopsy who qualified for active surveillance using 2011 National Comprehensive Cancer Network guidelines. No cases of high-risk (>= Gleason 4 + 3) cancer were identified on biopsy and, of the fifteen patients who underwent radical prostatectomy at our institution, none were pathologically upgraded to high-risk cancer. Thus, for patients with only low suspicion lesions, 107 (88%) patients either had no cancer or clinically insignificant disease. CONCLUSIONS The results obtained in the present study show that low suspicion lesions on mpMRI are associated with either negative biopsies or low-grade tumours suitable for active surveillance. Such patients have a low risk of harbouring high-risk prostate cancers.