Radiology - Research Publications
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ItemPathological predictors of 18F-DCFPyL prostate-specific membrane antigen-positive recurrence after radical prostatectomy(WILEY, 2022-06)OBJECTIVES: To assess the correlation of pathological radical prostatectomy (RP) specimen features and prostate-specific antigen (PSA) characteristics to imaging findings on subsequent 18 F-DCFPyL positron emission tomography/computed tomography (PET/CT) in patients with biochemical failure (BF). PATIENTS AND METHODS: Retrospective analysis of combined 18 F-DCFPyL PET/CT database of patients from centres in Australia and New Zealand was performed. A total of 205 patients presenting with BF after RP were included in this study. Imaging findings on 18 F-DCFPyL PET/CT were recorded and correlated with the PSA characteristics at BF and pathological features of the original tumour. RESULTS: Of the 205 patients, 120 (58.5%) had evidence of abnormal prostate-specific membrane antigen (PSMA) expression compatible with recurrent prostate cancer. Increasing PSA velocity (P = 0.01), International Society of Urological Pathology (ISUP) Grade Group (P = 0.02), lymphovascular invasion (P = 0.05) and nodal positivity (P = 0.02) at the time of RP were more likely to demonstrate PSMA positivity. Multivariable logistic regression revealed a higher PSA level prior to PSMA PET/CT (P < 0.01), adjuvant radiotherapy (P = 0.09), Gleason score ≥8 (P < 0.01) and nodal positivity (P = 0.05) were all predictive of PSMA positivity. CONCLUSION: 18 F-DCFPyL PET/CT positivity, both generally and site specific, correlates with PSA and RP pathological factors. Our results echo cohorts focussing on post-RP patients, those imaged with 68 Ga-PSMA and those concerning biochemical persistence. Nomograms that include risk factors for 'PSMA-positive recurrence' in the BF population may increase the catchment of patients with disease confined to the prostate bed or pelvis who have a greater probability of prolonged disease-free survival.
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ItemPEDAL protocol: a prospective single-arm paired comparison of multiparametric MRI and 18F-DCPFyl PSMA PET/CT to diagnose prostate cancer(BMJ PUBLISHING GROUP, 2022-09)INTRODUCTION: Prostate-specific membrane antigen positron emission tomography (PSMA-PET) has emerged as valuable imaging to assessing metastatic disease in prostate malignancy. However, there has been limited studies exploring the utility PSMA-PET as primary imaging assessing for index lesions prior to biopsy. The primary objective of this study is to compare the diagnostic accuracy of 18-fluorine PSMA (18F DCFPyL PSMA) PET scans to multiparametric MRI (mpMRI) to detect primary prostate cancer at prostate biopsy. METHODS AND ANALYSIS: The PEDAL trial is a multicentre, prospective, single-arm, paired comparison, non-randomised phase III trial in subjects considered for diagnostic prostate biopsy. Subjects who are eligible for a diagnostic mpMRI prostate will undergo additional same-day 18 F DCFPyl PSMA PET/CT of the chest, abdomen and pelvis. Software coregistration of the mpMRI and PSMA-PET/CT images will be performed. The reporting of the mpMRI prostate, PSMA-PET/CT and PSMA PET/MRI coregistration will be performed blinded. The diagnostic accuracy of PSMA PET/CT alone, and in combination with mpMRI, to detect prostate cancer will be assessed. Histopathology at prostate biopsy will be used as the reference standard. Sample size calculations estimate that 240 subjects will need to be recruited to demonstrate 20% superiority of PSMA-PET/CT. The sensitivity, specificity, positive predictive value and negative predictive value of the combination of mpMRI prostate and PSMA PET/CT compared with targeted and systematic prostate biopsy will be evaluated. It is hypothesised that PSMA PET/CT combined with mpMRI prostate will have improved diagnostic accuracy compared with mpMRI prostate alone for detection of prostate cancer in biopsy-naïve men, resulting in a significant impact on patient management. ETHICS AND DISSEMINATION: This study was approved by the independent Human Research Ethics Committee. Results will be published in peer-reviewed medical journals with eligible investigators will significantly contribute. TRIAL REGISTRATION NUMBER: ACTRN12620000261910.
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ItemCombination of MRI prostate and 18F-DCFPyl PSMA PET/CT detects all clinically significant prostate cancers in treatment-naive patients: An international multicentre retrospective study(WILEY, 2022-10)INTRODUCTION: Clinical and biochemical assessment and biopsies can miss clinically significant prostate cancers (csPCa) in up to 20% of patients and diagnose clinically insignificant tumours leading to overtreatment. This retrospective study analyses the accuracy of 18 F-DCFPyL PET/CT in detecting csPCa as a primary diagnostic tool and directly compares it with mpMRI prostate in treatment-naive patients. The two modalities are then correlated to determine whether they are better in combination, than either alone. METHODS: This is a retrospective dual-institution study of patients who underwent contemporaneous MRI and PSMA-PET between January 2017 and March 2020 with histologic confirmation. The images were re-reviewed and concordance between modalities assessed. Results were compared with histopathology to determine the ability of MRI and PSMA-PET to detect csPCA. RESULTS: MRI and PSMA-PET detected the same index lesion in 90.8% of cases with a kappa of 0.82. PET detected an additional 6.2% of index lesions which were MRI occult. MRI detected an additional 3.1% which were PET occult. No additional csPCa was identified on pathology which was not seen on imaging. The sensitivity of PSMA-PET in detecting csPCa is 96.7% and that of MRI is 93.4% with no statistically significant difference between the two (P = 0.232). Both modalities detected all four cases of non-csPCa with these being considered false positives. CONCLUSION: Both mpMRI and 18F-DCFPyL-PSMA-PET/CT have high sensitivity for detecting csPCa with high agreement between modalities. There were no synchronous csPCa lesions detected on pathology that were not detected on imaging too.
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ItemNon-prostate cancer tumours: incidence on 18F-DCFPyL PSMA PET/CT and uptake characteristics in 1445 patients.(Springer Science and Business Media LLC, 2022-07)PURPOSE: With increasing use of PSMA PET/CT in the staging and restaging of prostate cancer (PCa), the identification of non-prostate cancer tumours (NPCaT) has become an increasing clinical dilemma. Atypical presentations of PSMA expression in prostate cancer and expression in NPCaT are not well established. Understanding the normal and abnormal distribution of PSMA expression is essential in preparing clinically relevant reports and in guiding multidisciplinary discussion and decisions. METHODS: Retrospective review of 1445 consecutive 18F-DCFPyL PSMA PET/CT studies by experienced radiologists and nuclear medicine physicians. Lesions indeterminate for PCa were identified. Correlation was made with patient records, biopsy results, and dedicated imaging. Lesions were then categorized into four groups: 1. Confirmed prostate cancer, metastases, 2. NPCaT 3. Benign, and 4. Indeterminate lesions. RESULTS: 68/1445 patients had lesions atypical for prostate cancer metastases. These comprised 8/68 (11.8%) atypical prostate cancer metastases, 17/68 (25.0%) NPCaT, 29/68 (42.6%) indeterminate, and 14/68 (20.6%) benign. In the context of the entire cohort, these are adjusted to 8/1445 (0.6%), 17/1445 (1.2%), 29/1445 (2.0%), and 14/1445 (1.0%) respectively. With the exception of Renal Cell Carcinoma (RCC), NPCaT demonstrated no or low PSMA expression. A similar trend was also observed for indeterminate and benign lesions. Conversely, most atypical PCa metastases demonstrated intermediate or high PSMA expression. CONCLUSION: 18F-DCFPyL PSMA PET/CT detection of NPCaT is low. Lesions demonstrating intermediate to high PSMA expression were exclusively prostate cancer metastases, aside from RCC, and lesions detected in organs with high background expression.
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ItemNo Preview AvailablePSMA PET/CT to guide salvage treatment post prostatectomy: The IMPPORT trial(Elsevier BV, 2020-07)
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ItemQuantifying the Effect of Location Matching on Accuracy of Multiparametric Magnetic Resonance Imaging Prior to Prostate Biopsy-A Multicentre Study(ELSEVIER, 2020-07)BACKGROUND: Multiparametric magnetic resonance imaging (mpMRI) has shown promise to improve detection of prostate cancer over conventional methods. However, most studies do not describe whether the location of mpMRI lesions match that of cancer found at biopsy, which may lead to an overestimation of accuracy. OBJECTIVE: To quantitate the effect of mapping locations of mpMRI lesions to locations of positive biopsy cores on the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of mpMRI. DESIGN SETTING AND PARTICIPANT: We retrospectively identified patients having mpMRI of the prostate preceding prostate biopsy at three centres from 2013 to 2016. Men with targetable lesions on imaging underwent directed biopsy in addition to systematic biopsy. We correlated locations of positive mpMRI lesions with those of positive biopsy cores, defining a match when both were in the same sector of the prostate. We defined positive mpMRI as Prostate Imaging Reporting and Data System (PI-RADS) score ≥4 and significant cancer at biopsy as grade group ≥2. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Sensitivity, specificity, PPV, and NPV were calculated with and without location matching. RESULTS AND LIMITATIONS: Of 446 patients, 247 (55.4%) had positive mpMRI and 232 (52.0%) had significant cancer at biopsy. Sensitivity and NPV for detecting significant cancer with location matching (both 63.4%) were decreased compared with those without location matching (77.6% and 73.9%, respectively). Of the 85 significant cancers not detected by mpMRI, most were of grade group 2 (64.7%, 55/85). CONCLUSIONS: We report a 10-15% decrease in sensitivity and NPV when location matching was used to detect significant prostate cancer by mpMRI. False negative mpMRI remains an issue, highlighting the continued need for biopsy and for improving the standards around imaging quality and reporting. PATIENT SUMMARY: The true accuracy of multiparametric magnetic resonance imaging (mpMRI) must be determined to interpret results and better counsel patients. We mapped the location of positive mpMRI lesions to where cancer was found at biopsy and found, when compared with matching to cancer anywhere in the prostate, that the accuracy of mpMRI decreased by 10-15%.
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ItemEvaluation of the accuracy of multiparametric MRI for predicting prostate cancer pathology and tumour staging in the real world: an multicentre study(WILEY, 2019-08)OBJECTIVES: To assess the accuracy of multiparametric magnetic resonance imaging (mpMRI) for the detection of significant prostate cancer in men undergoing radical prostatectomy (RP) in an Australian multicentre setting, and to assess concordance between mpMRI and RP for local tumour staging and index lesion locations. PATIENTS AND METHODS: Men who underwent mpMRI within 12 months of RP between January 2013 and August 2016 at three Australian sites were included (Central Coast, NSW, St Vincents Hospital, Melbourne, Vic., and Bendigo Hospital, Vic.). The results of mpMRI were compared with the final RP specimen to analyse the performance of mpMRI for significant prostate cancer detection, index lesion localization, prediction of T3 disease and lymph node metastasis. A comparison between mpMRI cases performed using the technical and reporting specifications of Prostate Imaging Reporting and Data System (PI-RADS) version 1 and version 2 was also performed. Data analysis was performed using spss 24.0. RESULTS: A total of 235 cases were included for analysis. mpMRI PI-RADS score ≥3 had a 91% sensitivity and 95% positive predictive value (PPV) for significant prostate cancer at RP. The overall concordance between index lesion location on mpMRI and RP specimen was 75%. The sensitivity for predication of significant prostate cancer was higher in the PI-RADS version 2 cases compared with PI-RADS version 1 (87-99%; P = 0.005). Index lesion concordance was higher in the PI-RADS version 2 group (68% vs 91%; P = 0.002). mpMRI had a 38% sensitivity, 95% specificity, 90% PPV and 57% negative predictive value for extraprostatic disease. Sensitivity for prediction of T3 disease improved from 30% to 62% (P = 0.008) with PI-RADS version 2. CONCLUSIONS: In patients undergoing RP, an abnormal mpMRI is highly predictive (95% PPV) of significant prostate cancer, with an index lesion concordance of 75%. There has been a significant improvement in accuracy after the adoption of PI-RADS version 2 technical specifications and reporting criteria; however; further study is required to determine if this is attributable to improved experience with mpMRI or changes in the PI-RADS system.
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ItemFunding of prostate magnetic resonance imaging leads to fewer biopsies and potential savings to health systems in the management of prostate cancer(WILEY, 2021-05)OBJECTIVES: To assess the impact of the introduction of multiparametric magnetic resonance imaging of the prostate (mpMRIp) on the number of prostate biopsies performed in Australia. METHODS: Australian Medicare published statistics from 1 July 2007 to 30 June 2019 were obtained from publically available databases for prostate-specific antigen (PSA) testing, prostate biopsy, and mpMRIp. Analysis was divided into three time periods broadly based on availability of mpMRI to the Australian public: 2007-2012 (no mpMRIp), 2012-2018 (mpMRIp available, privately funded), and 2018-2019 (mpMRIp available with Medicare funding). Introduction of mpMRIp was hypothesised to reduce the number of prostate biopsies performed. PSA testing numbers were used as a control. The economics model, proposed by the Medical Services Advisory Committee (MSAC), was analysed for cost savings. RESULTS: Accounting for variations in PSA testing, the introduction of mpMRIp from 2012 coincided with a reduction in the number of prostate biopsies by an average of 354.7/month (95% CI 175, 534.4; P < 0.001). Whilst the number of mpMRIp performed for the initial 12 months was underestimated by the MSAC at 38 470 vs 20 149 (+$8.3 million Australian dollars), we estimate the annual savings from reduced number biopsies and biopsy-associated complications to be $13.2 ± 9.6 million. CONCLUSION: Availability of mpMRIp in Australia has correlated with a significant reduction in prostate biopsy rates, with an estimated annual saving of $13.2 ± 9.6 million. Government funding of this diagnostic service has the potential to improve health equity and save on health expenditure.