With the growing acceptance of the value of multi-parametric MRI (mpMRI) the detection, diagnosis and treatment of prostate cancer is undergoing a paradigm shift away from biomarkers and standard 12-core biopsies to imaging-based strategies with targeted biopsies.
In a 2015 Korean Journal of Urology review of mpMRI, the authors concluded that, “mpMRI, which is composed of T2WI and several functional sequences, is regarded as the single most accurate imaging modality for characterizing prostate cancer.”
In addition, the authors wrote that, “the role of mpMRI has been expanded to prostate biopsy, active surveillance, advanced disease detection, and local recurrence detection after radical prostatectomy. In this regard, urologists should acquire in-depth knowledge about mpMRI because it is a rapidly evolving imaging modality.”
One reason for the increasing use of mpMRI is the precise localization of significant prostate cancer before biopsy, which may be used for more accurate pretreatment stratification.
While the European Association of Urology, the American Urological Association and the National Comprehensive Cancer Network have all included mpMRI in their guidelines for prostate biopsy, active surveillance, and recurrent prostate cancer, consensus on imaging-directed treatment strategy is lagging.
Much as in the case of breast cancer, despite advances in imaging and biopsy, mastectomy remained the standard therapy for some time before lumpectomy and targeted radiation became standard, the same seems to be playing out in prostate cancer.
While T2-weighted sequences combined with several functional sequences including diffusion-weighted imaging, dynamic contrast-enhanced imaging, and/or magnetic resonance spectroscopy imaging are providing urologists with greater accuracy and confidence in characterizing prostate cancer, prostatectomy and radiation of the whole prostate remain the treatment strategies of choice.
At New York University Langone Perlmutter Cancer Center, researchers are taking a more targeted approach to using mpMRI data in treating prostate cancer. In an interview at the 2018 OncLive® State of the Science Summit™ on Genitourinary Cancers, reporter Caroline Seymour talked with Samir Taneja, MD, director of the NYU’s Urologic Oncology program about how they are using mpMRI data for treatment strategy.
“With the advent of the multiparametric MRI, which allows us to use different functional sequences to better assess the prostate and determine what’s cancer and what’s not, we're able to localize cancers accurately,” Dr. Taneja told Seymour. “NYU Langone is one of the early innovators in the area of prebiopsy MRI of the prostate. We think we can monitor the disease better than we used to be able to with fewer biopsies.”
To assess risk, Taneja says they first look at the T2-weighted image that provides an anatomic image, looking for dark areas that might represent cancer, or rounded areas or smudges that are darker than normal tissue. They improve on accuracy by adding functional imaging sequences using diffusion-weighted MRI, and gadolinium contrast. With the information about the density and metabolic rate of the lesion they apply the PI-RAD score to classify the tumor.
Dr. Taneja says as a result of that mpMRI data the Langone approach is currently shifting away from uniformly removing or irradiating the whole prostate to ablation techniques such as high-intensity focal ultrasound (HIFU), cryoablation or laser thermal therapy. “We have very early data on the effectiveness of that, but it is the imaging that has empowered us to do it,” Taneja said.
The Langone approach outlined by Dr. Taneja closely mirrors a new patient prostate cancer pathway that Professor Mark Emberton of the University College Hospital in London proposed at AUA 2017. He and his team suggest that if mpMRI data indicates high probability of cancer and if location is favorable then combining biopsy and HIFU treatment should be considered.
Prof. Emberton points out that mpMRI data makes it possible to discuss lesion location early with the patient allowing him to prepare for the possibility of focal therapy at the time of biopsy if the location can be reached with HIFU.
For a snapshot view of this new imaging-based algorithm SonaCare has prepared an infographic outlining the new screening/diagnosis, treatment and follow-up pathway suggested by Prof. Emberton.
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