How to cite: Stone NN. How Biopsy Length Influences Diagnosis and Treatment Planning. Grand Rounds in Urology. October 23, 2025. Accessed Apr 2026. https://grandroundsinurology.com/how-biopsy-length-influences-diagnostic-and-treatment-planning/
Summary
Nelson N. Stone, MD, Professor of Urology, Radiation Oncology, and Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, examines how biopsy core length influences diagnostic accuracy, the ability to successfully stay on active surveillance, and focal therapy targeting in prostate cancer.
Dr. Stone explains that conventional 18-gauge Tru-Cut® biopsy needles typically yield specimens shorter than their 20 mm notch length, despite being the clinical standard for decades. As risk stratification increasingly depends on precise pathology, cancer volume, and lesion mapping, reliance on shorter, inconsistent biopsy cores presents limitations. Dr. Stone describes the design of a novel adjustable biopsy device, developed with collaborators, to obtain substantially longer cores while preserving tissue integrity through structural ridges within the notch that stabilize tissue during capture.
Using software modeling of transperineal mapping biopsy data in 104 patients, Dr. Stone demonstrates that most prostate sites require core lengths exceeding current needle capability. He reviews literature showing that shorter cores correlate with Gleason upgrading at prostatectomy and that longer samples improve cancer detection. He further notes implications for MRI-guided biopsy: cognitive targeting often requires multiple samples, and because MRI often underestimates lesion margins, it may miss clinically significant contralateral disease, affecting focal therapy planning.
Dr. Stone proposes that longer biopsy cores that traverse base to apex may improve diagnostic accuracy, increase the number of patients who successfully stay on active surveillance, and improve focal therapy targeting.
About the 28th Annual Southwest Prostate Cancer Symposium:
Presented by Program Chairs Nelson N. Stone, MD, Richard G. Stock, MD, and William K. Oh, MD, this conference educated attendees about advances in the management of localized and advanced prostate cancer, with a focus on imaging, technology, and training in the related devices. It included a scientific session, as well as live demonstrations of surgical techniques.
ABOUT THE AUTHOR
Nelson N. Stone, MD, is Professor of Urology, Radiation Oncology, and Oncological Sciences at the Icahn School of Medicine at Mount Sinai and chief medical officer at Viomerse, Inc.
Dr. Stone earned his medical degree from the University of Maryland in 1979. He completed a Residency in General Surgery in 1981 at the University of Maryland, followed by a Residency in Urology at the University of Maryland. He then completed a Fellowship in Urologic Oncology at Memorial Sloan-Kettering Cancer Center and a Research Fellowship in Biochemical Endocrinology at Rockefeller University in 1986. He was Chief of Urology at Elmhurst Hospital Queens from 1986-1996.
Dr. Stone has founded several medical companies and serves on the editorial board of many scientific journals. He is a member of many professional societies, including the Prostate Conditions Education Council, the Society for Minimally Invasive Therapy, the New York State Urological Society, the American Association of Clinical Urologists, and the American Urologic Association. Dr. Stone has participated in approximately 25 research studies on prostate cancer and has authored more than 500 articles, abstracts, and book chapters, primarily on prostate cancer. He invented the real-time technique for prostate brachytherapy in 1990 and has trained more than 5,000 physicians worldwide through his company ProSeed. His most recent company, Viomerse, creates synthetic body parts (phantoms) for surgical training and has recently released an extended reality remote training platform.
