Assessing Metastatic Disease in Advanced Prostate Cancer: It's Time to Change Imaging

Abstract

Two articles on imaging of advanced prostate cancer (APC) were published recently, one in European Urology Focus [1] and one in European Urology [2]. Both were produced by an international panel (United Kingdom, Belgium, Germany, Italy, and the United States) with the most experience in whole-body magnetic resonance imaging (WB-MRI) of APC. Thiswas done under the scientific direction of two key clinical opinion leaders: urologist Bertrand Tombal (Belgium) and clinical trials oncologist Johann de Bono (United Kingdom). These two papers need to be read in tandem. These articles were prepared in response to recommendations for standardisation of modern imaging made at the Advanced Prostate Cancer Consensus Conference 2015 (APCCC; St. Gallen, Switzerland). The Prostate Cancer Working Group (PCWG3; 2016) also pointed out the limitations of current imaging for direction of patient management and for clinical trials of therapeutics. These articles are aimed at urologists and oncologists who treat patients with APC, and they cover aspects of current practice and emerging evidence for changes in practice based on clinical trials [1,2]. A critical review was written about currently used imaging technologies, such as bone scans and computed tomography (CT) scans, and how current limitations can be addressed by functional imaging methods including positron emission tomography (PET) with CT and WB-MRI [1]. The critical review recognises the central role of imaging in directing clinical care, but it is critical of current reliance on bone and CT scans for directing patient care. The authors provide cogent arguments for the need for change and application of new imaging modalities. In particular, the review paper addresses the need for more accurate imaging in APC when metastatic disease can be concluded as definitively present or absent and subsequently can guide patient management [1]. These papers do not address the issues of detectingmicroscopic or minimal metastatic disease [1,2]. The promotion of modern imaging methods is framed in light of new data on the potential benefits of more accurate imaging detection of metastases and potential impacts for therapymonitoring. This summary of the impacts of imaging cannot be found elsewhere in the literature—this is a highlight. The paper assesses imaging methods that have potential clinical utility today rather than the promise of better imaging tomorrow [1]. That is why there is a focus on the potential utility of fluorocholine-PET/CT and on the emerging role of WB-MRI. Prostate-specific membrane antigen–PET scanning is not mentioned in this review but is increasinglyused indifferentparts of EuropeandtheUnited States. Imaging techniques, including WB-MRI and PET/CT, demonstrate capabilities that go beyond current practise and will be unfamiliar to many readers; as such, they require explanation. The illustrations (in the review, supplementary figures, and appendix) demonstrate the power of new technology for multiregional evaluations, for metastasis detection, and for response assessment (in bone and soft tissues). E U RO P E AN URO LOGY 7 1 ( 2 0 1 7 ) 9 3 – 9 5