Development of standardized image interpretation for 68Ga-PSMA PET/CT to detect prostate cancer recurrent lesions.
Stefano Fanti, Silvia Minozzi, Joshua James Morigi, Frederik Giesel, Francesco Ceci, Christian Uprimny, Michael S Hofman, Matthias Eiber, Sarah Schwarzenbock, Paolo Castellucci, Cristina Bellisario, Stéphane Chauvie, Fabrizio Bergesio, Louise Emmett, Uwe Haberkorn, Irene Virgolini, Markus Schwaiger, Rodney J Hicks, Bernd J Krause, Arturo Chiti
Author Information
Stefano Fanti: Nuclear Medicine Unit, University of Bologna, S. Orsola Hospital Bologna, Bologna, Italy.
Silvia Minozzi: Department of Epidemiology, Lazio Regional Health Service, Rome, Italy.
Joshua James Morigi: Department of Diagnostic Imaging, St. Vincent's Public Hospital, Sydney, Australia. joshuamorigi@me.com. ORCID
Frederik Giesel: Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany.
Francesco Ceci: Nuclear Medicine Unit, University of Bologna, S. Orsola Hospital Bologna, Bologna, Italy.
Christian Uprimny: Department of Nuclear Medicine, Medical University Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.
Michael S Hofman: Centre for Molecular Imaging, Department of Cancer Imaging, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, 3000, Australia.
Matthias Eiber: Department of Nuclear Medicine, Technical University Munich, Munich, Germany.
Sarah Schwarzenbock: Department of Nuclear Medicine, University Medical Centre, Rostock, Germany.
Paolo Castellucci: Nuclear Medicine Unit, University of Bologna, S. Orsola Hospital Bologna, Bologna, Italy.
Cristina Bellisario: Department of Cancer Screening, Centre for Epidemiology and Prevention in Oncology (CPO), University Hospital "Città della Salute e della Scienza di Torino", Turin, Italy.
Stéphane Chauvie: Medical Physics Division, Santa Croce e Carle Hospital, Cuneo, Italy.
Fabrizio Bergesio: Medical Physics Division, Santa Croce e Carle Hospital, Cuneo, Italy.
Louise Emmett: Department of Diagnostic Imaging, St. Vincent's Public Hospital, Sydney, Australia.
Uwe Haberkorn: Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany.
Irene Virgolini: Department of Nuclear Medicine, Medical University Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.
Markus Schwaiger: Department of Nuclear Medicine, Technical University Munich, Munich, Germany.
Rodney J Hicks: Centre for Molecular Imaging, Department of Cancer Imaging, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, 3000, Australia.
Bernd J Krause: Department of Nuclear Medicine, University Medical Centre, Rostock, Germany.
Arturo Chiti: Nuclear Medicine, Humanitas Cancer Center, Humanitas Clinical and Research Hospital, Via Manzoni 56, 20089, Rozzano, MI, Italy.
METHODS: After primary treatment, biochemical relapse (BCR) occurs in a substantial number of patients with prostate cancer (PCa). PET/CT imaging with prostate-specific membrane antigen based tracers (68Ga-PSMA) has shown promising results for BCR patients. However, a standardized image interpretation methodology has yet to be properly agreed. The aim of this study, which was promoted and funded by European Association of Nuclear Medicine (EANM), is to define standardized image interpretation criteria for 68Ga-PSMA PET/CT to detect recurrent PCa lesions in patients treated with primary curative intent therapy (radical prostatectomy or radiotherapy) who presented a biochemical recurrence. In the first phase inter-rater agreement between seven readers from seven international centers was calculated on the reading of 68Ga-PSMA PET/CT images of 49 patients with BCR. Each reader evaluated findings in five different sites of recurrence (local, loco-regional lymph nodes, distant lymph nodes, bone, and other). In the second phase the re-analysis was limited to cases with poor, slight, fair, or moderate agreement [Krippendorff's (K) alpha<0.61]. Finally, on the basis of the consensus readings, we sought to define a list of revised consensus criteria for 68Ga-PSMA PET/CT interpretation. RESULTS: Between-reader agreement for the presence of anomalous findings in any of the five sites was only moderate (K's alpha: 0.47). The agreement improved and became substantial when readers had to judge whether the anomalous findings were suggestive for a pathologic, uncertain, or non-pathologic image (K's alpha: 0.64). K's alpha calculations for each of the five sites of recurrence were also performed and evaluated. First Delphi round was thus conducted. A more detailed definition of the criteria was proposed by the project coordinator, which was then discussed and finally agreed by the seven readers. After the second Delphi round only four cases of disagreement still remained. These were evaluated for a final round, allowing a final agreement table to be written. CONCLUSION: We hope that by developing these consensus guidelines on the interpretation of 68Ga-PSMA PET/CT, clinicians reporting these studies will be able to provide more consistent clinical reports and that within clinical trials, abnormality classifications will be harmonized, allowing more robust assessment of its diagnostic performance.
