Risk of reclassification and novel tools in active surveillance.

Objective: Low-risk prostate cancer usually has an indolent course, and in this scenario, active surveillance (AS) is currently the preferred management, reducing overtreatment without compromising oncologic outcomes in well-selected patients. Two pillars of this strategy are patient selection and adequate monitoring strategy to detect early progression, leading to active treatment in the window of curability. The aim of this review is to assess the novel available tools and their role in AS. Methods: We conducted a comprehensive review of the current literature addressing the risk of reclassification and studies evaluating traditional and emerging diagnostic and prognostic tools, including imaging modalities, biomarkers, and genomic classifiers, which could decrease reclassification rates and minimize the burden of serial exams during follow-up and, especially, the frequency of biopsies, which are still necessary to evaluate progression. Results: The most significant follow-up cohorts demonstrate long-term treatment rates ranging from 30% to 45%, and 36% of low-risk prostate cancer patients have an upgrade in radical prostatectomy specimens. Despite the emergence of new diagnostic and prognostic tools, few of them have been validated or included in the assessment of eligible patients for AS. In the current guidelines, a combination of cT stage, Gleason score, prostate-specific antigen value, prostate-specific antigen density, and number of positive cores in biopsy is used to select patients for AS. However, various risk factors have been associated with the risk of reclassification, which reveals the need to incorporate better tools that may contribute to better risk stratification of patients eligible for AS. Conclusion: Although AS is feasible and safe, the risk of progression is of great concern for patients and physicians, and monitoring is also an important part of the therapeutic strategy. Novel risk stratification tools are promising but need further validation to improve results and decrease the burden and anxiety that monitoring can bring to patients.