The role of MRI in active surveillance for men with localized prostate cancer

Purpose of review Active surveillance is the preferred management strategy for men with low-risk prostate cancer. Challenges in this field include improving patient selection, optimizing follow-up strategies, and identifying appropriate triggers for intervention. Advances in multiparametric MRI (mpMRI) have lead to improved detection of prostate tumors, and MRI has emerged as a tool to monitor men on active surveillance. We aim to review the latest developments in mpMRI to monitor active surveillance patients and describe areas of future research. Recent findings mpMRI targeted prostate biopsy results in a higher detection rate of significant prostate cancer, and a lower probability of detecting insignificant tumors, compared to systematic biopsy. mpMRI-targeted biopsies have improved diagnosis of significant anterior tumors. A small proportion of high-grade tumors is missed by mpMRI and targeted biopsy. However, the majority of these tumors are small-volume, Gleason grade 3 + 4 cancers, and their clinical significance is unknown. Summary mpMRI and targeted prostate biopsy have emerged as tools to improve the accuracy of systematic biopsy to select patients for active surveillance. The role of mpMRI to monitor and trigger intervention in these patients is understudied, and integration of MRI data with clinical characteristics can help many men avoid routine confirmatory biopsy.