Sunday June 30, 2019 from 07:30 to 09:00
Qualitative correlations of positron-emission tomography-detected intra-prostatic lesions with sextant transrectal ultrasound biopsy and post-prostatectomy histopathology results
Khalil Hetou1, Glenn Baumann2,4, Jonathan Thiessen3, Madeleine Moussa5, Irina Rachinsky5, Zahra Kassam5, Stephen E. Pautler1,2, Shiva Nair1, Ting Yim Lee2,3, John F. Vallian6, Aaron Ward2,4, Joseph Chin1,2.
1Urology, University of Western Ontario, London, ON, Canada; 2Oncology, University of Western Ontario, London, ON, Canada; 3Medical Imaging, University of Western Ontario, London, ON, Canada; 4Medical Physics, University of Western Ontario, London, ON, Canada; 5Pathology, University of Western Ontario, London, ON, Canada; 6Chemistry and Chemical Biology, McMaster University, Hamilton, ON, Canada
Canadian Institutes of Health Research (CIHR). . Ontario Institute for Cancer Research, Smarter Imaging Program – Prostate (OICR).
Introduction: As part of a Prostate Cancer Image-Guided Interventions Study, we investigated positron-emission tomography (PET) imaging with two different tracers in the preoperative setting, for possible correlation with clinical parameters, using transrectal ultrasound (TRUS)-guided biopsy (Bx) as the reference.
Methods: A sextant template was created to compare Bx and PET findings with final pathological whole-mount specimens. The sum of maximum standardized uptake (SUVmax) values from all positive foci was calculated for each case to assess for correlation with extra-prostatic extension (EPE).
Results: F-18 Cohort: 138 prostate sites from 23 men were identified. Site-specific sensitivity and specificity of PET for any disease were 44.8% and 72.7%, respectively. For clinically significant disease (CS) (GS of 3+4 and higher) sensitivity increased to 55.2% but had a specificity of 62%. GS-stratified analysis showed no significant difference in PET-positive lesions among GS subgroups (p=0.18). Bx had a sensitivity of 20% but a specificity of 96.6% for CS disease. Mean total SUVmax in men with pT2 was similar to that in men with pT3 (9.0 vs. 8.8) (p=0.61). DCFPyL cohort: 120 prostate sites were identified from 20 men. Site-specific sensitivity and specificity of PET for any disease were 28.4% and 74.3%, respectively. Bx had a sensitivity of 60.3% and specificity of 66.7% for any disease. Sensitivity and specificity of PET for CS disease increased to 32% and 76%, respectively. Bx had a sensitivity of 32% and a specificity of 80% for CS disease. GS-stratified analysis showed no significant difference in PET-positive lesions among GS subgroups (p=0.73). Mean total SUVmax in men with pT2 (n=12) was 5.72 (standard dveiation [SD] 1.4) vs. 14.89 (SD 3.73) in men with pT3 (p=0.016).
Conclusions: On qualitative, sextant-wise assessment, preoperative Bx and PET had modest correlation with RP specimens. Higher PSMA PET SUVmax among men with EPE suggests possible utility for treatment planning. Quantitative (voxelwise) correlative studies are underway.