JU INSIGHT Magnetic Resonance Imaging for Localizing Prostate Cancer Near the Urethra in Focal Gland Ablation Candidates
By: Neal Patel, MD, Weill Cornell Medicine, New York, New York; Alexa Hughes, MS University of California, Los Angeles; JJ H. Zhang, MD, University of California, Los Angeles; Wayne Brisbane, MD, University of Florida, Gainesville; Ali Rastegarpour, MD, University of California, Los Angeles; Sohrab Afsahir, MD, University of California, Los Angeles; Lorna Kwan, MPH, University of California, Los Angeles; Anissa V. Nguyen, MPH, University of California, Los Angeles; Anthony Sisk, MD, University of California, Los Angeles; Steve Raman, MD, University of California, Los Angeles; Robert Reiter, MD, MBA, University of California, Los Angeles | Posted on: 18 May 2023
Patel N, Hughes A, Zhang JH, et al. Utility of magnetic resonance imaging for localizing prostate cancer near the urethra in men who are candidates for focal gland ablation. J Urol. 2023;209(5):911-917.
Study Need and Importance
The utilization of focal gland ablation to treat localized prostate cancer is increasing substantially. However, there is still significant concern regarding long-term efficacy, especially given the high rates of biopsy-proven treatment failures. By identifying men who are candidates for focal gland ablation but who underwent radical prostatectomy, a critical analysis of their whole-mount pathology can potentially help discern mechanisms of treatment failure with focal gland ablation. Given that ablative therapies often require the use of a protective urethral catheter or limit energy delivery near the urethra, identifying the frequency that tumors are within close proximity to the urethra can help better guide treatment selection.
What We Found
In a cohort of men who would have been potential candidates for focal gland ablation but underwent a radical prostatectomy, we found that 72% of the tumors are within 5 mm of the urethra (see Figure). Thus, if this tissue is not adequately ablated, in-field recurrences could occur in the periurethral tissue. In order to better select patients who could benefit from alternative treatment ablation modalities, prostate MRI can be used to calculate tumor to urethral distance as the sensitivity of detecting tumors within 5 mm of the urethra is 77%.
Limitations include the retrospective design of the study and the hypothetical mechanism of treatment failure for focal gland ablation. Future studies should consider periurethral biopsies in men who had focal gland ablation with a urethral protective device to determine the frequency of periurethral recurrences.
Interpretation for Patient Care
Prostate MRI is already widely used to help select which men are candidates for focal gland ablation. The tumor to urethra distance can be calculated using the MRI to help better tailor treatment choice and/or energy modality for focal gland ablation.