MRI and surveillance

In this review, we summarize the recent advances in modern imaging, particularly multiparametric (mp) MRI and its role in the selection and monitoring of patients on active surveillance.

Current diagnostic pathway has some limitations in selecting patients with insignificant prostate cancer for active surveillance. Hence, percentage of men under active surveillance for insignificant prostate cancer and reclassified as significant cancer at 2 years is 20-30%. It is mainly because of anterior cancer underdiagnosis by systematic posterior biopsies. mp-MRI is accurate for significant cancer detection and staging, including anterior cancers, which represent 20% of cancers in an unselected population of men with suspicious prostate-specific antigen elevation. One way to reduce the risk of underestimation is to target the needle on significant cancer identified at prebiopsy anatomical and functional imaging, so that detection and personalized risk stratification can be improved. MRI reveals greater volume of cancers and higher grade than systematic 12-core biopsies. MRI 95% negative predictive value has the potential to avoid biopsy series for monitoring patients under active surveillance.

Upon confirmation of these results, MRI may be used to better select patients for active surveillance inclusion. Incorporation of mp-MRI into active surveillance selection criterias for patients with low-risk prostate cancer can reduce the number of patients reclassified at subsequent biopsies because of better initial prognosis evaluation. In addition to additional cost, MRI requires a highly skilled team to obtain information adequate to drive clinical decisions.