Role of Magnetic Resonance Imaging in Prostate Cancer Screening: A Pilot Study Within the Göteborg Randomised Screening Trial.

BACKGROUND Magnetic resonance imaging (MRI) and targeted biopsies (TB) have shown potential to more accurately detect significant prostate cancer compared with prostate-specific antigen (PSA) and systematic biopsies (SB). OBJECTIVE To compare sequential screening (PSA+MRI) with conventional PSA screening. DESIGN, SETTING, AND PARTICIPANTS Of 384 attendees in the 10th screening round of the Göteborg randomised screening trial, 124 men, median age 69.5 yr, had a PSA of ≥ 1.8 ng/ml and underwent a prebiopsy MRI. Men with suspicious lesions on MRI and/or PSA ≥ 3.0ng/ml were referred for biopsy. SB was performed blinded to MRI results and TB was performed in men with tumour-suspicious findings on MRI. Three screening strategies were compared (PSA ≥ 3.0+SB; PSA ≥ 3.0+MRI+TB and PSA ≥ 1.8+MRI+TB). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Cancer detection rates, sensitivity, and specificity were calculated per screening strategy and compared using McNemar's test. RESULTS AND LIMITATIONS In total, 28 cases of prostate cancer were detected, of which 20 were diagnosed in biopsy-naïve men. Both PSA ≥ 3.0+MRI and PSA ≥ 1.8+MRI significantly increased specificity compared with PSA ≥ 3.0+SB (0.92 and 0.79 vs 0.52; p<0.002 for both), while sensitivity was significantly higher for PSA ≥ 1.8+MRI compared with PSA ≥ 3.0+MRI (0.73 vs 0.46, p=0.008). The detection rate of significant cancer was higher with PSA ≥ 1.8+MRI compared with PSA ≥ 3.0+SB (5.9% vs 4.0%), while the detection rate of insignificant cancer was lowered by PSA ≥ 3.0+MRI (0.3% vs 1.2%). The primary limitation of this study is the small sample of men. CONCLUSION A screening strategy with a lowered PSA cut-off followed by TB in MRI-positive men seems to increase the detection of significant cancers while improving specificity. If replicated, these results may contribute to a paradigm shift in future screening. PATIENT SUMMARY Major concerns in prostate-specific antigen screening are overdiagnosis and underdiagnosis. We evaluated whether prostate magnetic resonance imaging could improve the balance of benefits to harm in prostate cancer screening screening, and we found a promising potential of using magnetic resonance imaging in addition to prostate-specific antigen.