Advances in radiology and molecular imaging have the potential to significantly change how clinicians diagnose, stage, and monitor response to therapy in patients with prostate cancer. However, there are limited data comparing these next-generation imaging modalities to each other and to conventional imaging in men with advanced prostate cancer. ASCO recently released a new set of guidelines to provide evidence- and expert-based recommendations for the optimal use of imaging in this patient population.1
“There has been an explosion of options for imaging in patients with advanced prostate cancer,” Guideline Panel Co-Chair Alberto Vargas, MD, of Memorial Sloan Kettering Cancer Center, said. “Where there used to be just one or two different imaging modalities used, we now have a variety of newer techniques and PET-imaging radionuclides.”
“The type of imaging used will depend on the clinical scenario and disease state.”— Alberto Vargas, MD
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Some examples include the growing use of radiopharmaceuticals targeting the prostate-specific membrane antigen receptor and the recently approved C11 choline and F18 fluciclovine for positron-emission tomography (PET) imaging in men with suspected recurrence based on elevated prostate-specific antigen (PSA).
The expert panel included members from ASCO, the Society of Abdominal Radiology, American College of Radiology, Society of Nuclear Medicine and Molecular Imaging, American Urological Association, American Society for Radiation Oncology, and Society of Urologic Oncology.
“Right off the bat, we wanted to have broad stakeholder involvement,” Guideline Panel Co-Chair Edouard J. Trabulsi, MD, of Sidney Kimmel Medical College at Thomas Jefferson University, said. “The panel needed to include not just the radiology community, but every specialty that sees these patients.”
Panel members conducted a review of available literature published from 2013 to August 2018 that compared two or more imaging modalities, as well as noncomparative studies that reported on the efficacy of a single modality. However, because the field is rapidly evolving, the guideline was also designed to preemptively address certain imaging modalities that are promising but not yet approved by the U.S. Food and Drug Administration (FDA), or that have less available data.
“Right off the bat, we wanted to have broad stakeholder involvement. The panel needed to include not just the radiology community, but every specialty that sees these patients.”— Edouard J. Trabulsi, MD
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“Some of the more novel imaging techniques have a bit less evidence strength, with retrospective or single-institution trials,” Dr. Trabulsi said. “The evaluation of those agents included a bit more consensus and expert opinion in the recommendations.”
First among the recommendations is that imaging be used for all patients with advanced prostate cancer and that one or more of the conventional imaging modalities and/or the next-generation imaging modalities be employed. “However, this is not a blanket statement—saying that the same imaging should be used in all patients,” Dr. Vargas clarified. “The type of imaging used will depend on the clinical scenario and disease state.”
The guideline provides examples of different scenarios. For example, for a patient with newly diagnosed, high-risk, localized prostate cancer, the recommendation states that when conventional imaging is negative, next-generation imaging may be offered for potential detection of disease sites amenable for treatment. In cases where conventional imaging is equivocal, next-generation imaging may provide clarification.
In men with a rising PSA level after prostatectomy and negative conventional imaging who are considering salvage radiotherapy, next-generation imaging, such as C11 choline or F18 fluciclovine PET/CT (computed tomography) or PET/MRI (magnetic resonance imaging), whole-body MRI, and/or F18 NaF PET/CT, should be offered.
For men with nonmetastatic, castration-resistant prostate cancer, next-generation imaging should only be offered if a change in the clinical care is being contemplated.
Numerous other examples are provided in the full guideline.
“A big part of this guideline is not to approach prostate cancer monolithically, but to acknowledge there is a spectrum of disease, disease treatments, and disease states as well as to individualize appropriate imaging based on the expected clinical utility of the information you may receive from that imaging,” Dr. Trabulsi said.
Both guideline co-chairs also acknowledged that this field is in a constant state of evolution, with more tracers expected to be approved by the FDA soon. “No matter how much effort we put into generating up-to-date guidelines, the nature of the field means it will require frequent updates,” Dr. Vargas said.
The formulation of the guidelines also provided an opportunity to identify where the gaps in the literature are. “Everyone involved in prostate cancer can use these gaps as research ideas for the community to entertain and to generate the necessary data to make our recommendations even stronger,” Dr. Vargas said.
DISCLOSURE: For full disclosures of study authors, visit ascopubs.org.
REFERENCE
1. Trabulsi EJ, Rumble RB, Jadvar H, et al: Optimum imaging strategies for advanced prostate cancer: ASCO guideline. J Clin Oncol. January 15, 2020 (early release online).
Originally published in ASCO Daily News. © American Society of Clinical Oncology. ASCO Daily News, January 16, 2020. All rights reserved.
