Editorial Comment: The Number of Cancer-Involved Regions in Patients With Prostate Cancer Diagnosed by Magnetic Resonance Imaging/Ultrasound-Guided Fusion Prostate Biopsy Is a New Tumor Metric Associated With the Increased Risk of Adverse Pathology at Radical Prostatectomy

One central challenge in localized prostate cancer is accurate preoperative risk stratification. Yusim et al1 evaluated MRI/ultrasound fusion biopsy–derived tumor burden metrics: the number of cancer-involved regions (NCIR) and maximum cancer core length (MCCL), as predictors of adverse pathology at radical prostatectomy. Both metrics were independently associated with extracapsular extension, seminal vesicle invasion, and positive surgical margins, whereas PSA, biopsy Grade Group, and prostate imaging reporting and data system score were not significant in multivariable analyses, highlighting the added value of spatial tumor burden assessment. A key strength of this work is the use of a predefined biopsy strategy based on systematic anatomical coverage. By dividing the prostate into sextants and sampling each region following targeted biopsy, NCIR and MCCL are anchored to spatial tumor distribution rather than to the absolute number of cores, potentially providing a more biologically meaningful representation of tumor burden. Beyond biopsy-derived parameters, imaging is increasingly recognized as a cornerstone of contemporary risk stratification. The externally validated risk stratification proposed by Mazzone et al2 provides insight into the role of multiparametric magnetic resonance imaging as an independent contributor to risk assessment, reinforcing the concept that radiological parameters capture clinically meaningful information beyond biopsy-derived variables alone. Additional sources of heterogeneity warrant consideration. The lack of formal definitions of urologist and pathologist expertise is relevant, given the operator-dependent nature of MRI-guided biopsy performance and histopathological interpretation, particularly in single-center analyses.3,4 Finally, a subset of patients underwent prostate-specific membrane antigen-positron emission tomography imaging for staging, yet PET-derived intraprostatic parameters were not reported, representing a missed opportunity for additional biological and prognostic refinement. These tools, along with the NCIR and MCCL reported by the authors, could further refine the risk stratification of prostate cancer, which may help inform treatment decisions.