Incidence of significant prostate cancer after negative MRI and systematic biopsy in the FUTURE trial

Objectives To assess the proportion of clinically significant (cs) prostate cancer (PCa) found during follow-up in patients with negative systematic biopsy (SB) followed by non-suspicious multiparametric magnetic resonance imaging (mpMRI) and persistent clinical suspicion of PCa compared to the general population. Patients and Methods A prospective study in a subgroup of patients from a multicentre randomized controlled trial was conducted between 2014 and 2017, including 665 men with prior negative SB with a persistent elevated prostate-specific antigen and/or suspicious digital rectal examination undergoing mpMRI. All patients with negative SB and Prostate Imaging-Reporting and Data System (PI-RADS) <= 2 on mpMRI entered biochemical follow-up. Follow-up data until December 2021 were collected by reviewing institutional hospital records and the Dutch Pathology Registry (PALGA). The primary outcome was the observed number of csPCa (Gleason >= 3 + 4/International Society of Urological Pathology grade group >= 2) cases during follow-up compared to the expected number in the general population (standardized incidence ratio [SIR]). Results In total, 431 patients had non-suspicious mpMRI and entered biochemical follow-up. After a median (interquartile range) follow-up of 41 (23-57) months, 38 patients were diagnosed with PCa, of whom 13 (3.0%) had csPCa. The SIR for csPCa was 4.3 (95% confidence interval 2.3-7.4; total excess of eight cases). A higher risk of a positive biopsy for (cs)PCa based on the European Randomized Study of Screening for Prostate Cancer risk calculator and a suspicious repeat MRI (PI-RADS >= 3) were significant predictive factors for csPCa. Conclusion After negative prior biopsy and non-suspicious mpMRI the risk of csPCa is low. However, compared to the general population, the risk of csPCa is increased despite the high negative predictive value of mpMRI. More research focusing on biochemical and image-guided risk-adapted diagnostic surveillance strategies is warranted.