Personalized risk-adapted models in prostate cancer during active surveillance using MRI-a narrative review

The presence of histologically defined prostate cancer (PCa) is common and rises with age. Nevertheless, histological evidence of PCa does not always lead to clinically evident or life-threatening disease, and we know that PSA-based population screening can find twice the prevalence of PCa than would present via clinical routes. The PROTECT study randomized men diagnosed through PSA screening, to surgery, radiotherapy, or active monitoring. At 15 years, PCa-related deaths ranged from 2.1% in the surgery group to 2.9% in the active monitoring group, while the risk of death from other causes was 22%. Modern PCa diagnosis uses MRI to determine who needs a biopsy and how it is done. Multiparametric MRI can selectively detect PCa of higher grade and volume, which is more likely to be associated with progression, metastases, and death, and hence to benefit from treatment. MRI and MRI-targeted biopsies are recommended prior to enrolment in active surveillance (AS) programs for accurate risk classification. The UCLH AS cohort based on per-cause MRI evaluations has shown baseline Gleason grade and MRI index lesion visibility to be strong predictors of progression to treatment. Serial evaluation with MRI has been codified with the PRECISE recommendations to support MRI-based monitoring during AS. AS recommendations have extended to certain favorable-intermediate risk cancers. The Movember International Consensus Meeting has determined a dynamic risk-stratified AS approach to be the highest-ranked research priority. We review the impact of MRI on AS from patient selection to risk stratification, and the development of MRI-led personalized AS protocols. KEY POINTS: Question Standardized protocols are not able to address the heterogeneity of men on active surveillance for PCa and are burdened by unnecessary examinations. Findings MRI can improve the selection of men for active surveillance, predict time to treatment, and risk-stratify patients at risk of progression. Clinical relevance MRI-led risk-adapted protocols may reduce the burden of active surveillance on patients, improve adherence, and reduce healthcare costs.