Virtual Global Summit on Precision Diagnosis and Treatment of Prostate Cancer Archives

Recent Advancements in PI-RADS: mpMRI vs. bpMRI

Posted by Jelle Barentsz, MD, PhD | Oct 2021

Jelle Barentsz, MD, PhD, Professor of Radiology at the Nijmegen Medical Center of Radboud University in Nijmegen, The Netherlands, begins his talk on recent advancements in the prostate imaging-reporting and data system (PI-RADS) by asserting the value of local magnetic resonance imaging (MRI) in the diagnosis of prostate cancer. He cites the 2019 European Association of Urology (EAU) guidelines, which recommend performing a prostate MRI before biopsy, and points out that this results in 2,000,000 MRIs annually. He asserts there is a need for fast MRI, citing a PI-RADS committee position on MRI without the use of gadolinium (Gd)-based contrast medium (biparametric MRI, or bpMRI) which suggests that if certain prerequisites are satisfied, bpMRI may offer a fast MRI option for some patients. Dr. Barentsz then cites three studies. The first compared screenings using multi-parametric MRI (mpMRI) with bpMRI and found the prostate cancer detection rate was identical (but it failed to specify which patients had insignificant vs. clinically-significant prostate cancer [csPCa]). The second study compared single-plane (or “fast”) bpMRI vs. mpMRI and concluded mpMRI found nine percent more csPCa; however Dr. Barentsz points out the study was underpowered and used an older technique, a 1.5T endorectal coil (ERC) MRI. Dr. Barentsz explores data from the third study, which found that mpMRI and fast bpMRI demonstrated equal sensitivity in finding csPCa, at 95 percent. He outlines the pros and cons of the fast bpMRI, emphasizing that for less-experienced radiologists, the procedure increases uncertainty. Dr. Barentsz explains that the PI-RADS committee concludes there is a need to have both unenhanced MRI and contrast-enhanced MRI approaches available for prostate-cancer diagnosis. Dr. Barentsz then turns to the issue of costs, showing data comparing the direct cost of mpMRI, bpMRI, and “fast” bpMRI, specifying that mpMRI is more than twice as costly as “fast” bpMRI. Dr. Barentsz asserts that dynamic contrast-enhanced (DCE)-MRI is a better choice for patients with a previous negative bpMRI with persistent clinical suspicion, DWI-artifacts (e.g., hip prosthesis), and for doctors with a lower level of expertise. Dr. Barentsz then explains situations when bpMRI (no DCE) may be an appropriate choice, such as in a low-risk (screening) population or when there is a high chance of having significant prostate cancer. Dr. Barentsz concludes his talk by stating that bpMRI can be effective for very skilled prostate radiologists. He reiterates that DCE helps find small tumors, reduces uncertainty, and increases confidence. He also states that the prerequisites for bpMRI are good quality imaging, and specifies the need for objective quality assessment and control as well as training and certification.

Evaluation and Management of Localized and Recurrent Prostate Cancer: Genetic Cancer Profiling

Posted by Alan Pollack, MD, PhD | Jul 2021

Alan Pollack, MD, PhD, Professor and Chair in the Department of Radiation Oncology at University of Miami Health, looks at genetic cancer profiling for prostate cancer risk assessment and its implications for treatment. He begins with a discussion of the development of a habitat risk scoring system for prostate cancer which, via quantitative pixel by pixel assessment, can generate high-risk volumes for targeting. Dr. Pollack then moves on to transcriptome analysis using genomic classifiers like Decipher, noting that these classifiers have a relationship with Gleason score, though it is not absolute, and can predict 10-year distant metastasis. He also considers how to understand genomic risk of habitats from quantitative MRI, observing the significant connections between radiogenomic features and transcriptomic features. Dr. Pollack concludes with a discussion of how genomic signatures might influence critical management, going through how Decipher scores could change risk stratification and highlighting several trials looking at habitat targeted radiotherapy.

Current and Emerging Role of Radiogenomics in Risk Assessment

Posted by John Feller, MD | Jul 2021

John Feller, MD, Founding Partner and Medical Director of Desert Medical Imaging, Assistant Clinical Professor in the Departments of Radiology at Loma Linda University and at Riverside School of Medicine, Chief of Radiology and Partner of the American Medical Center in China reviews data for evaluating radiogenomics in terms of risk stratification for focal therapy and for developing novel combination therapies. Dr. Feller introduces a phase II study on laser focal therapy of prostate cancer that shows the ability of responders to focal therapy to be distinguished from non-responders with support from findings showing lower PSA values and lower PSA density in responders as opposed to nonresponders, and another study on the Decipher Genomics Resource Information Database (GRID), revealing that genes can be used to differentiate responders from non-responders. He then discusses a phase II clinical trial on outpatient trans-rectal MR-guided Laser Focal Therapy that found that short-term and intermediate-term oncologic control achievable in 79% of patients with initial treatment. He concludes that MpMRI followed by genomics shows promise for risk stratification for focal therapy and that multiple complex data sources present an opportunity for artificial intelligence.

Current and Emerging Imaging Tools for Improving Risk Assessment and Selection of Patients for Biopsy

Posted by Clare Tempany, MB, BCh, BAO | Jun 2021

Clare Tempany, MD, the Ferenc A. Jolesz Professor of Radiology at Harvard Medical School in Boston, Massachusetts, summarizes evidence for multiparametric magnetic resonance imaging’s (mpMRI) utility in prostate cancer diagnosis, and goes over recent developments in its use. She first looks at selection criteria for biopsy and biopsy type, including history, digital rectal examination (DRE), prostate specific antigen (PSA), and imaging, arguing that mpMRI is particularly helpful in allowing patients to avoid unnecessary biopsies. Dr. Tempany then defines state-of-the art mpMRI as featuring diffusion/apparent diffusion coefficient, being T2-weighted, being IV contrast/dynamic contrast enhanced, and as being reported using the PI-RADS v2.1 assessment. She goes over the PI-RADS assessment categories, considers the findings of multiple publications backing up the value of mpMRI as compared to transurethral ultrasound (TRUS), and looks at evidence supporting guidance indicating patients with PI-RADS 3 lesions should get a biopsy. Dr. Tempany follows this up by summarizing a paper from the PI-RADS steering committee on how PI-RADS and mpMRI should be used. Suggestions include performing mpMRI in most men suspected of having clinically-significant disease, providing a safety net of monitoring for patients who decline immediate biopsy after low-likelihood MRI findings, and using a combination of systematic and targeted biopsies in biopsy-naive patients while only using targeted biopsies for patients with prior negative findings on TRUS. Dr. Tempany then notes that the AUA, EAU, and NICE guidelines all now recommend MRI before biopsy, and also observes that MRI is cost-effective if it leads to the avoidance of biopsy. She concludes by listing areas for future development, including multi-omics, molecular pathology, germline mutations, CTC/blood biomarkers, and mass spectrometry.

Non-Invasive Molecular Imaging and its Impact on Management of the Localized Disease and Suspected Recurrence

Posted by Andrei H. Iagaru, MD, FACNM | May 2021

Andrei H. Iagaru, MD, FACNM, Professor of Radiology and Chief of the Division of Nuclear Medicine and Molecular Imaging at Stanford University, enumerates the applications of a dual radiopharmaceutical-targeted imaging approach using prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptor (GRPR) in prostate cancer care. He explains that while PSMA-targeted PET imaging is more widely accepted, GRPR-targeted imaging may identify tumors that PSMA-targeted PET misses and vice versa. Therefore, combining the two can give clinicians a clearer understanding of the patient’s cancer. Dr. Iagaru suggests that the dual target approach can be particularly helpful in guiding biopsy decisions in patients with suspected prostate cancer, as well as in helping identify all lesions prior to local therapy with high-intensity focused ultrasound (HIFU) or brachytherapy. Using two targets can also sometimes allow clinicians to find more lesions prior to prostatectomy and pelvic lymph node dissection. He notes that targeting GRPR with 68Ga-RM2 can be particularly useful in patients with biochemical recurrence, since PSA velocity is higher in 68Ga-RM2 positive scans than in 68Ga-RM2 negative scans. Dr. Iagaru concludes by considering the potential of these two targets in theranostics, noting that phase 3 trials of theranostics with PSMA are awaiting results and that phase 1 and 2 trials of theranostics with GRPR are promising.