Clinical outcome following a low-suspicion multiparametric prostate MRI or benign MRI-guided biopsy to detect prostate cancer: A follow-up study in men with prior negative transrectal ultrasound-guided biopsies

PURPOSE: To assess the future risk of detecting significant prostate cancer following either a low-suspicion MRI or suspicious MRI with benign MRI-guided biopsies in men with prior negative systematic biopsies.

MATERIALS AND METHODS: 289 prospectively enrolled men underwent MRI followed by repeated systematic and targeted biopsies of any suspicious lesions at baseline. In total, 194 patients with either a low-suspicion MRI or benign target biopsies were suitable for this study. Those who were negative for prostate cancer at baseline were followed up for at least three years. We calculated the negative predictive values of MRI in ruling out any prostate cancer and significant prostate cancer defined as: a) any core with Gleason score (GS) > 6 or b) > 2 positive cores/cancerous core ≥ 50%.

RESULTS: Prostate cancer was detected in 38/194 (20%) patients during the median study period of 47 months (interquartile range 43-52). The overall negative predictive value of MRI in ruling out any and significant prostate cancer was 80% (156/194) and 95% (184/194), respectively. No patient with a low-suspicion MRI had intermediate/high grade cancer (Gleason score > 6). The majority of patients with no cancer during follow-up [132/156 (85%)] had decreasing levels of prostate-specific-antigen and could be monitored in primary care.

CONCLUSION: A low-suspicion MRI in men with prior negative systematic biopsies has a high negative predictive value in ruling out longer term significant cancer. Therefore, immediate repeated biopsies are of limited clinical value and could be avoided even if prostate-specific-antigen levels are persistently elevated.