Diagnostic yields in patients with suspected prostate cancer undergoing MRI as the first-line investigation in routine practice

Abstract

To document cancer yields of magnetic resonance imaging (MRI)-directed biopsies in men with suspected prostate cancer referred to secondary care. Men with suspected cancer undergoing multiparametric prostate MRI as the first-line investigation were included in the present study. Systematic transrectal prostate biopsies with/without cognitive targeted biopsies were performed. Diagnostic yields of International Society of Urological Pathology (ISUP) ≥2 cancers by the Prostate Imaging Reporting and Data System (PI-RADS) category were recorded. Impacts of prostate-specific antigen (PSA) density on biopsy results and yields of non-targeted biopsies in MRI non-suspicious prostate sextants assessed. Of 262 men (90.5% biopsy naive), 86 (33%) MRI examinations were negative (PI-RADS 1-2) and 176 (67%) positive (PI-RADS 3: 8%; PI-RADS 4: 21%; PI-RADS 5: 38%). Two hundred and thirteen of 262 patients underwent a biopsy. ISUP ≥2 cancer detection rates were 8% (5/61) for PI-RADS 1-2, 18% (3/17) for PI-RADS 3, 49% (22/45) for PI-RADS 4, and 80% (72/90) for PI-RADS 5. Proportions of ISUP ≥2 increased with higher PSA densities in positive patients (%ISUP ≥2 for PSA density groups <0.12, 0.12 to <0.15 and ≥ 0.15 was 0%, 0%, 25% for PI-RADS 3, 21%, 33%, 68% for PI-RADS 4 and 40%, 83%, 89% for PI-RADS 5 respectively). ISUP ≥2 cancers were twice as likely in tumour adjacent sextants (52% versus 24%), without upgrading of gland level histology from insignificant to clinically significant prostate cancer by the sampling of normal-appearing tumour non-adjacent sextants. One third of men can avoid biopsy after negative MRI. Cancer detection rates increase with PSA density values within positive MRI suspicion categories. Sampling normal-appearing tumour non-adjacent sextants may be unnecessary for whole-gland therapy.