Laurence Klotz, MD, FRCSC

Laurence Klotz, MD, FRCSC

University of Toronto

Toronto, Ontario, Canada

Laurence Klotz, MD, FRCSC, is a professor of surgery at the University of Toronto and the Sunnybrook Chair of Prostate Cancer Research. Dr. Klotz was the founding editor-in-chief of both the Canadian Journal of Urology and the Canadian Urology Association Journal (CUAJ), and he is now editor emeritus of the CUAJ. Dr. Klotz obtained his medical degree and completed his residency at the University of Toronto. He was also a uro-oncology fellow at Memorial Sloan Kettering Cancer Center in New York.

Dr. Klotz has 550 peer review publications and eight books. He coined the phrase “active surveillance” and successfully championed this approach for men with favorable-risk prostate cancer against substantial resistance. He was the associate editor of the Journal of Urology, responsible for prostate cancer, for eight years. Dr. Klotz received the Queen’s Jubilee Medal for outstanding public service, the University of Toronto's Lister Prize, the Society of Urologic Oncology’s SUO Medal, the American Urological Association’s Richard Williams Award, the University of Toronto's Lifetime Achievement Award, the Canadian Urological Association Lifetime Achievement Award, and the Harold Warwick Award from the Canadian Cancer Society for “outstanding contributions to cancer control.” In 2015 he was inducted as a Member of the Order of Canada, Canada’s highest civilian award.

Talks by Laurence Klotz, MD, FRCSC

Genomics and Natural History of MRI Invisible vs Visible Cancers – Implications for Clinical Practice

Genomics and Natural History of MRI Invisible vs Visible Cancers – Implications for Clinical Practice

Posted by | Nov 2024

Laurence Klotz, MD, FRCSC, explores the genomics and natural history of MRI-visible versus invisible prostate cancers and their clinical implications.

In this 12-minute presentation, he highlights that while MRI is transformative in identifying significant prostate cancer, it misses about 15% of “invisible cancers.” Recent research reveals that the invisibility of these tumors correlates with favorable genomic profiles, including fewer genetic aberrations and reduced aggressivity.

Dr. Klotz presents compelling evidence linking visible tumors to adverse molecular features and worse clinical outcomes, whereas invisible cancers are largely indolent. He underscores the potential of radiogenomics in guiding treatment decisions, advocating for management strategies based on imaging rather than solely histology.

Dr. Klotz considers avoiding unnecessary systematic biopsies in favor of targeted MRI approaches can minimize patient anxiety and reduce overdiagnosis of insignificant cancers. However, challenges remain in addressing gray areas, such as PI-RADS 3 lesions and visible but low-grade cancers, which may require more nuanced management.

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Optimization of Prostate Biopsy – Micro-Ultrasound versus MRI (OPTIMUM)

Optimization of Prostate Biopsy – Micro-Ultrasound versus MRI (OPTIMUM)

Posted by | Nov 2024

Laurence Klotz, MD, FRCSC, introduces the OPTIMUM trial, a landmark international study comparing micro-ultrasound and MRI for prostate cancer detection. In this 9-minute presentation, Dr. Klotz explains that micro-ultrasound, operating at 29 MHz, offers three times greater resolution than conventional ultrasound. Using a PRIMUS scoring system analogous to PI-RADS, micro-ultrasound demonstrates its utility in identifying highly sensitive lesions.

Dr. Klotz details the trial’s three-arm design, which involves MRI with conventional ultrasound, MRI with micro-ultrasound, and micro-ultrasound alone to assess non-inferiority and complementary detection capabilities.

Dr. Klotz emphasizes the trial’s importance for minimizing bias and improving diagnostic practices, particularly given its potential to replace or complement MRI. He highlights the study’s robust design, comprehensive objectives, and international collaboration, anticipating its transformative impact on prostate cancer diagnosis and management.

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Alan Partin Lecture: The Genomics and Natural History of Visible vs. Invisible Cancers

Alan Partin Lecture: The Genomics and Natural History of Visible vs. Invisible Cancers

Posted by | Oct 2024

Laurence Klotz, MD, FRCSC, presents the newly-emerging and provocative concept of MRI visibility as a predictor of prostate cancer tumor aggressivity in the Alan W. Partin Distinguished Lecture at IPCU 34. Given that more definitive data on the subject develops, and the urological community accepts it, this could imply significant changes to practice.

Currently, the concern over invisible cancers drives a lot of interventions, such as systemic biopsies in patients who have already undergone targeted biopsies and/or received negative imaging results. Patients on active surveillance derive anxiety from the possibility of having untreated occult cancer.

The clinical implication of imaging-based monitoring has many advantages, such as psychological benefit to the patient, and reduced cost and burden of care from avoiding systematic biopsies. Recent genomic and clinical studies support the idea that tumors invisible on MRI imaging have much more favorable genetics and natural history tha

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High Resolution Micro-Ultrasound: Going Beyond MRI

High Resolution Micro-Ultrasound: Going Beyond MRI

Posted by | Jul 2024

Laurence Klotz, MD, FRCSC, illustrates the value of high resolution micro-ultrasound over that of multiparametric MRI (mpMRI) in prostate cancer staging and diagnosis. He begins by reviewing the history, strengths, and limitations of mpMRI, and he presents his own history with high resolution micro-ultrasound.

Dr. Klotz then explains the differences between high resolution micro-ultrasound and conventional ultrasound. He compares the sensitivity, precision, and accuracy of high resolution micro-ultrasound against those of mpMRI and conventional ultrasound.

Dr. Klotz concludes by examining the efficacy of combining mpMRI and high resolution micro-ultrasound for prostate cancer diagnosis and staging. He presents data from ongoing trials supporting the use of high resolution micro-ultrasound as a complement to mpMRI.

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An Expert Discussion of Testosterone Nadir and Clinical Outcomes in Patients with Advanced Prostate Cancer: A Post Hoc Analysis of Triptorelin Pamoate Phase III Studies

An Expert Discussion of Testosterone Nadir and Clinical Outcomes in Patients with Advanced Prostate Cancer: A Post Hoc Analysis of Triptorelin Pamoate Phase III Studies

Posted by | Jun 2024

In a program supported by Verity Pharmaceuticals, Neal D. Shore, MD, FACS, Medical Director for the Carolina Urologic Research Center and Chief Medical Officer, Strategic Growth and Pharmacy, GenesisCare US, Myrtle Beach, South Carolina, and Laurence Klotz, MD, FRCSC, Professor of Surgery at the University of Toronto and the Sunnybrook Chair of Prostate Cancer Research in Toronto, Ontario, Canada, discuss Dr. Klotz’s paper published in January 2024 entitled, “Testosterone Nadir and Clinical Outcomes in Patients with Advanced Prostate Cancer: Post Hoc Analysis of Triptorelin Pamoate Phase III Studies.”
Dr. Klotz describes the objective of the study was to evaluate whether low nadir testosterone during treatment with triptorelin pamoate, a luteinizing hormone-releasing hormone (LHRH) agonist, is associated with improved clinical outcomes in patients with advanced prostate cancer using a retrospective analysis of clinical trial data. He discusses how data was pooled from three prospective, 9–12-month Phase III studies of triptorelin monotherapy in patients with advanced prostate cancer

Dr. Klotz also addresses the overall survival (OS) and disease-specific survival (DSS) by testosterone suppression group, assessed by Kaplan–Meier analysis with a log-rank test. He concludes the review by describing how, in the sample size comprised of 592 patients, low nadir testosterone achieved during treatment with the LHRH agonist triptorelin was associated with improved OS and DSS in patients with advanced prostate cancer.

Dr. Klotz and Dr. Shore then discuss the impact of the results from this trial and the potential future direction of treatment options for men with prostate cancer.

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