Surgery (RMH) - Research Publications
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ItemSynchronous vs independent reading of prostate-specific membrane antigen positron emission tomography (PSMA-PET) and magnetic resonance imaging (MRI) to improve diagnosis of prostate cancer(Wiley, 2023-05-01)Objectives: To identify whether synchronous reading of multiparametric magnetic resonance imaging (mpMRI) and 68Ga-PSMA-11 positron emission tomography (PET)/computed tomography (prostate-specific membrane antigen [PSMA-PET]) images can improve diagnostic performance and certainty compared with mpMRI/PSMA-PET reported independently and synthesized, while also assessing concordance between imaging modalities and agreement with histopathology. Methods: This was a retrospective analysis of 100 patients randomly selected from the PRIMARY trial, a prospective Phase II multicentre imaging trial. Three dual-trained radiologist/nuclear medicine physicians re-reported the mpMRI and PSMA-PET both independently and synchronously for the same patients in random order, blinded to previous results. Diagnostic performance was assessed for mpMRI/PSMA-PET images read synchronously or independently and then synthesized. Agreement between imaging results and histopathology was examined. ‘Concordance’ between imaging modalities was defined as overlapping lesions. Reporting certainty was evaluated by the individual reporters for each modality. Results: International Society of Urological Pathology Grade Group ≥2 cancer was present in 60% of patients on biopsy. Synchronous reading of mpMRI/PSMA-PET increased sensitivity compared to mpMRI or PSMA-PET alone (93% vs 80% vs 88%, respectively), although specificity was not improved (63% vs 58% vs 78%, respectively). No significant difference in diagnostic performance was noted between mpMRI/PSMA-PET read synchronously and mpMRI or PSMA-PET reported independently and then synthesized. Most patients had concordant imaging (60%), while others had discordant lesions only (28%) or a mixture (concordant and discordant lesions; 12%). When mpMRI/PSMA-PET findings were concordant and positive, 95% of patients had clinically significant prostate cancer (csPCa). When PSMA-PET alone was compared to synchronous PSMA-PET/MRI reads, there was an improvement in reader certainty in 20% of scans. Conclusion: Synchronous mpMRI/PSMA-PET reading improves reader certainty and sensitivity for csPCa compared to mpMRI or PSMA-PET alone. However, synthesizing the results of independently read PSMA-PET and mpMRI reports provided similar diagnostic performance to synchronous PSMA-PET/MRI reads. This may provide greater flexibility for urologists in terms of referral patterns, reducing healthcare system costs and improving efficiencies in prostate cancer diagnosis.
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ItemTwo decades of FDG-PET/CT in seminoma: exploring its role in diagnosis, surveillance and follow-up(BMC, 2022-10-08)BACKGROUND: Survivors of testicular cancer may experience long-term morbidity following treatment. There is an unmet need to investigate techniques that can differentiate individuals who need additional therapy from those who do not. 2-18fluoro-deoxy-D-glucose (FDG) positron emission tomography (PET) with computerised tomography (CT) may be helpful in select settings and may be used outside of current evidence-based recommendations in real-world practice. METHODS: A institutional FDG-PET/CT database of scans performed between 2000 and 2020 for adults with testicular seminoma was interrogated. Endpoints of interest included the positive (PPV) and negative (NPV) predictive value of FDG-PET/CT for identifying active seminoma (defined by progressive radiology, response to treatment or biopsy); or no active seminoma within 24-months for patients with stage 1 and advanced seminoma. An exploratory analysis examining predictive role of SUVmax was also performed. RESULTS: 249 patients met eligibility criteria for the analysis, including 184 patients with stage 1 and 77 patients with advanced testicular seminoma. Of 193 FDG-PET/CT performed in stage 1 seminoma with available follow-up data, 79 were performed during active surveillance. 18 (23%) of these were positive, all of which had confirmed recurrent seminoma (PPV 100%). Of 45 negative FDG-PET/CT during active surveillance, 4 recurrences developed corresponding to a NPV 91%. When clinical suspicion precipitated FDG-PET/CT (n = 36): PPV 100%, NPV 86%. Of 145 FDG-PET/CT in advanced seminoma with available follow-up data, 25 (17%) were performed at baseline (within 2 months of diagnosis), 70 (48%) post-treatment for evaluation of treatment response and 50 (34%) during follow-up following prior curative treatment. 10 (14%) post-treatment FDG-PET/CT were positive corresponding to a PPV 60%. Of 46 negative FDG-PET/CT, 5 recurrences occurred (NPV 89%). During follow-up after prior curative treatment, 24 (50%) FDG-PET/CT were positive corresponding to a PPV 83%; of 20 negative FDG-PET/CT, 1 recurrence occurred, NPV 95%. When clinical suspicion indicated FDG-PET/CT (n = 36): PPV 100%, NPV 94%. CONCLUSION: FDG-PET/CT offers high PPV for identifying seminoma and accurately predicts non-recurrence across a clinically relevant 24-months. Notably, FDG-PET/CT may prevent unnecessary treatment in 45% of patients undergoing investigation for clinical suspicion of recurrence during follow-up of advanced seminoma. The use of FDG-PET/CT in selected patients now, may help prevent unnecessary treatment of people with testicular seminoma.
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ItemImpact of Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography in the Management of Oligometastatic Renal Cell Carcinoma(ELSEVIER, 2022-10)BACKGROUND: Prostate-specific membrane antigen (PSMA) is overexpressed in the neovasculature of renal cell carcinoma (RCC). However, there remains limited evidence regarding the use of PSMA positron emission tomography/computed tomography (PET/CT) in RCC. OBJECTIVE: To assess the impact of PSMA PET/CT in the management of metastatic RCC. DESIGN SETTING AND PARTICIPANTS: This was a retrospective review of patients who underwent PSMA PET/CT from 2014 to 2020 for restaging or suspected metastatic RCC in a tertiary academic setting. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Management plans before and after PSMA PET/CT were recorded. Impact was classified as high (change of treatment intent, modality, or site), medium (change in treatment method), or low. Secondary outcomes included the patient-level detection rate, PSMA PET/CT parameters, sensitivity, and comparison to CT and, if available, fluorodeoxyglucose (FDG) PET/CT. RESULTS AND LIMITATIONS: Sixty-one patients met the inclusion criteria, of whom 54 (89%) had clear cell RCC. PSMA-positive disease was detected in 51 patients (84%). For 30 patients (49%) there was a change in management due to PSMA PET/CT (high impact, 29 patients, 48%). In 15 patients (25%), more metastases were detected on PSMA PET/CT than on CT. The sensitivity of combined PSMA PET/CT and diagnostic CT was 91% (95% confidence interval 77-98%). In a subcohort of 40 patients, the detection rate was 88% for PSMA and 75% for FDG PET/CT (p = 0.17). The maximum standardised uptake value (SUVmax) was higher for PSMA than for FDG PET/CT (15.2 vs 8.0; p = 0.02). Limitations include selection bias due to the retrospective design, and a lack of corresponding histopathology for all patients. CONCLUSIONS: PSMA PET/CT is a promising imaging modality in metastatic RCC and led to a change in management in 49% of patients. PSMA PET/CT detected additional metastases compared to CT in 25% of patients and registered a significantly higher SUVmax than FDG PET/CT. Prospective studies are required to further define its role. PATIENT SUMMARY: We report on a group of patients undergoing a new type of imaging for suspected advanced kidney cancer, called PSMA PET/CT. This imaging changed the management plan in 49% of the patients. PSMA PET/CT detected metastases in 84% of our patients and detected more metastases than computed tomography imaging in 25%.
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ItemNo Preview AvailableIs Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography Imaging Cost-effective in Prostate Cancer: An Analysis Informed by the proPSMA Trial(ELSEVIER, 2021-03)BACKGROUND: Before integrating prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) into routine care, it is important to assess if the benefits justify the differences in resource use. OBJECTIVE: To determine the cost-effectiveness of PSMA-PET/CT when compared with conventional imaging. DESIGN, SETTING, AND PARTICIPANTS: A cost-effectiveness analysis was developed using data from the proPSMA study. proPSMA included patients with high-risk prostate cancer assigned to conventional imaging or 68Ga-PSMA-11 PET/CT with planned health economics data collected. The cost-effectiveness analysis was conducted from an Australian societal perspective. INTERVENTION: 68Ga-PSMA-11 PET/CT compared with conventional imaging (CT and bone scan). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome from proPSMA was diagnostic accuracy (nodal and distant metastases). This informed a decision tree analysis of the cost per accurate diagnosis. RESULTS AND LIMITATIONS: The estimated cost per scan for PSMA PET/CT was AUD$1203, which was less than the conventional imaging cost at AUD$1412. PSMA PET/CT was thus dominant, having both better accuracy and a lower cost. This resulted in a cost of AUD$959 saved per additional accurate detection of nodal disease, and AUD$1412 saved for additional accurate detection of distant metastases. The results were most sensitive to variations in the number of men scanned for each 68Ga-PSMA-11 production run. Subsequent research is required to assess the long-term costs and benefits of PSMA PET/CT-directed care. CONCLUSIONS: PSMA PET/CT has lower direct comparative costs and greater accuracy compared to conventional imaging for initial staging of men with high-risk prostate cancer. This provides a compelling case for adopting PSMA PET/CT into clinical practice. PATIENT SUMMARY: The proPSMA study demonstrated that prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) better detects disease that has spread beyond the prostate compared with conventional imaging. Our analysis shows that PSMA PET/CT is also less costly than conventional imaging for the detection of disease spread. This research was presented at the European Association of Nuclear Medicine Scientific Meeting in October 2020.
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ItemUtility of 68Ga prostate specific membrane antigen - positron emission tomography in diagnosis and response assessment of recurrent renal cell carcinoma(WILEY, 2017-06)INTRODUCTION: Prostate specific membrane antigen (PSMA) positron emission tomography (PET) is an emerging imaging modality in prostate cancer. However, 68 Ga-PSMA-PET may also have diagnostic utility in the setting of renal cell carcinoma (RCC). We investigate the differential role of 18 F-fluorodeoxyglucose (FDG) and PSMA-PET/CT scanning in patients with oligometastatic RCC. In particular, we focus on the utility of PSMA-PET for diagnostic evaluation of isolated or limited metastases planned for local surgery or radiation, as well as the potential utility of PSMA-PET for therapeutic response assessment in patients receiving stereotactic ablative body radiotherapy (SABR). METHODS: We present a retrospective series of eight patients in which comparative imaging modalities are evaluated against PSMA-PET scanning. FDG-PET and PSMA-PET scans were performed prior to definitive treatment (either surgery or SABR) of limited recurrent disease. Response assessment after SABR was performed with both PET imaging modalities at multiple time points in a subset of four patients. RESULTS: Prostate specific membrane antigen uptake is typically more intense than FDG in RCC. In all but two cases, one of which was papillary carcinoma, FDG-PET and PSMA-PET are concordant for detection of sites of disease. We demonstrate for the first time the differential kinetics of post-treatment response using PSMA and FDG-PET, with a more rapid metabolic response observed on FDG-PET. Both modalities demonstrate response earlier than morphological appearances on CT or MRI imaging. CONCLUSIONS: Our series suggests that PSMA shows early promise as a diagnostic and therapeutic response assessment tool in patients with metastatic RCC receiving definitive local therapies.
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ItemA prospective randomized multicentre study of the impact of gallium-68 prostate-specific membrane antigen (PSMA) PET/CT imaging for staging high-risk prostate cancer prior to curative-intent surgery or radiotherapy (proPSMA study): clinical trial protocol(WILEY, 2018-11)BACKGROUND: Accurate staging of patients with prostate cancer (PCa) is important for therapeutic decision-making. Relapse after surgery or radiotherapy of curative intent is not uncommon and, in part, represents a failure of staging with current diagnostic imaging techniques to detect disease spread. Prostate-specific membrane antigen (PSMA) positron-emission tomography (PET)/computed tomography (CT) is a new whole-body scanning technique that enables visualization of PCa with high contrast. The hypotheses of this study are that: (i) PSMA-PET/CT has improved diagnostic performance compared with conventional imaging; (ii) PSMA-PET/CT should be used as a first-line diagnostic test for staging; (iii) the improved diagnostic performance of PSMA-PET/CT will result in significant management impact; and (iv) there are economic benefits if PSMA-PET/CT is incorporated into the management algorithm. OBJECTIVES AND METHODS: The proPSMA trial is a prospective, multicentre study in which patients with untreated high-risk PCa will be randomized to gallium-68-PSMA-11 PET/CT or conventional imaging, consisting of CT of the abdomen/pelvis and bone scintigraphy with single-photon emission CT/CT. Patients eligible for inclusion are those with newly diagnosed PCa with select high-risk features, defined as International Society of Urological Pathology grade group ≥3 (primary Gleason grade 4, or any Gleason grade 5), prostate-specific antigen level ≥20 ng/mL or clinical stage ≥T3. Patients with negative, equivocal or oligometastatic disease on first line-imaging will cross over to receive the other imaging arm. The primary objective is to compare the accuracy of PSMA-PET/CT with that of conventional imaging for detecting nodal or distant metastatic disease. Histopathological, imaging and clinical follow-up at 6 months will define the primary endpoint according to a predefined scoring system. Secondary objectives include comparing management impact, the number of equivocal studies, the incremental value of second-line imaging in patients who cross over, the cost of each imaging strategy, radiation exposure, inter-observer agreement and safety of PSMA-PET/CT. Longer-term follow-up will also assess the prognostic value of a negative PSMA-PET/CT. OUTCOME AND SIGNIFICANCE: This trial will provide data to establish whether PSMA-PET/CT should replace conventional imaging in the primary staging of select high-risk localized PCa, or whether it should be used to provide incremental diagnostic information in selected cases.
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