We sincerely thank Dr. Carbin for the thoughtful and constructive editorial comments on our article entitled “The number of cancer-involved regions in patients with prostate cancer diagnosed by MRI/ultrasound-guided fusion prostate biopsy is a new tumor metric associated with increased risk of adverse pathology at radical prostatectomy.”1 We greatly appreciate the careful reading of our work and the balanced discussion of both its clinical implications and its limitations. We fully agree with several important points raised in the commentary. First, as correctly noted, our study cohort is relatively small and derived from a single institution. This reflects the strict inclusion criteria and the uniform MRI/US fusion prostate biopsy protocol used at our center. We agree that external validation in larger, multicenter data sets will be important before broad clinical adoption of cancer-involved regions (NCIR) as a risk stratification metric. Second, we agree that the definition of adverse pathology is not yet entirely uniform across studies and societies. In our work, we deliberately used a definition focused on pathologic tumor extension (extraprostatic extension, seminal vesical invasion, and positive surgical margins >3 mm) because these features most directly affect staging and treatment decisions. We support the call for greater standardization in reporting adverse pathological outcomes. Third, the commentary correctly highlights that MRI/US fusion prostate biopsy metrics can be influenced by biopsy protocol and sampling intensity. For this reason, we proposed the NCIR rather than the absolute number of positive cores, since regional involvement is less dependent on the total number of cores obtained and better reflects the tumor's spatial distribution.2,3 Nevertheless, we acknowledge that variability in operator technique and protocol remains an important consideration.4 We also agree that the lack of predictive value of PSA, biopsy grade group, and clinical stage in our multivariable model likely reflects the relative homogeneity of our cohort (clinical stage ≤ T2 and PSA ≤ 20 ng/ml), as discussed in the manuscript. This design was intended to focus the analysis on tumor burden metrics derived from MRI/US fusion prostate biopsies. We are grateful that the editorial comment recognized the potential clinical relevance of combining maximum cancer core length and the NCIR when counseling patients and planning treatment strategies in the MRI/US fusion biopsy era. We thank Dr. Carbin again for the insightful commentary and for placing our findings in a broader clinical and research context.
Mabjeesh et al. (Sun,) studied this question.