EAU 2019: Debate: Is MRI-Targeted Biopsy Enough?
One logical question that arises is: if a man undergoes an MRI fusion biopsy, does he also require a standard transrectal ultrasound (TRUS) guided template biopsy to improve diagnostic accuracy. This question was debated during the imaging in prostate cancer podium session at the 2019 European Association of Urology (EAU) 2019 annual meeting in Barcelona, Spain. The question for the debate was: Is MRI-targeted biopsy alone enough?
Dr. Kasivisvanathan, a urologist from London, Great Britain, argued on the pro side that an MRI-fusion biopsy alone is enough for accurate diagnosis and that a standard template biopsy does not need to be performed at the same time. He began by arguing that standard TRUS biopsy only has a 48% sensitivity for the diagnosis of clinically significant prostate cancer and will often miss lesions. He then argued that even transperineal template biopsy misses clinically significant cancer in some cases. He advocates for utilizing a pragmatic test which balances appropriate sampling of the prostate gland while avoiding overdiagnosis of insignificant cancer. He believes that targeted biopsy alone is this very test. He argued for the advantages of MRI targeted biopsy alone include quicker time, fewer side effects, reduced burden on pathologist (less cores to evaluate), higher quality pathology, reduced equipment requirements, and greater physician capacity to perform the procedure. He then showed data which shows that standard TRUS biopsy leads to overdiagnosis of insignificant prostate cancer in many cases. 90 - 93% of clinically significant cancers are detected by MRI targeted biopsies alone. He concluded that MRI targeted biopsies reduce overtreatment, use fewer resources, and improve the risks/benefit balance in favor of prostate cancer treatment.
A rebuttal was then given by Dr. Guillaume Ploussard from Toulouse, France. He argued that a standard templated TRUS biopsy is necessary in addition to an MRI targeted biopsy. He began by stating that there are two main goals of prostate biopsies: to detect clinically significant cancer and to provide the most accurate prognostic assessment of the disease in order to guide the ideal treatment modality. He doesn’t debate that MRI targeted biopsies have been shown in the literature to be superior to standard template biopsies, but he does feel that combining both an MRI targeted biopsy and a standard biopsy improves the sensitivity of disease detection and helps with prognostication of the disease. Ploussard notes that in 2019 there are still no Phase III non-inferiority trials in MRI positive patients that compare MRI targeted biopsy alone to MRI targeted biopsy + standard biopsy. He then highlighted prospective data showing that standard biopsy does detect up to 10% additional Gleason Grade 3-5 malignancies in patients who have also undergone an MRI targeted biopsy. He next argued that standard biopsy helps to improve the prognostic assessment because secondary pathologic features such as tumor length, core involvement, and number of positive cores have all been shown to be independent predictors of upstaging/upgrading in multiple models. Ploussard also noted that there could be intratumoral heterogeneity and that other lesions within the prostate, not necessarily the one that is targetable by MRI, could drive the aggressiveness of the disease. He summarized that we should be honest with our patients about the pros and cons of performing a standard biopsy in addition to targeted biopsy. Pros are that there is an improved sensitivity of detection of clinically significant disease, and improved prognostic assessment, but the cons are an increased detection of clinically insignificant disease and a possible increase in low-grade adverse events due to more biopsy specimens.
The moderator of the debate summarized the arguments from each urologist. MRI targeted biopsy alone reduced unnecessary testing and reduces the diagnosis of clinically insignificant prostate cancer, but likely misses a small number of clinically significant lesions that could have been picked up had a standard biopsy been performed concurrently. Due to time constraints that the audience was unable to vote on which side they felt gave a better argument.
Presented by: Veeru Kasivisvanathan, MD1 and Guillaume Ploussard, MD, PhD2
1. Department of Urology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
2. Saint-Jean Languedoc Hospital and Institut Universitaire du Cancer - Oncopole, Toulouse, France
Written by: Brian Kadow, MD. Society of Urologic Oncology Fellow, Fox Chase Cancer Center at the 34th European Association of Urology (EAU 2019) #EAU19, conference in Barcelona, Spain from March 15-19, 2019.