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PURPOSE As prostate-specific membrane antigen (PSMA) positron emission tomography (PET) becomes increasingly available in the United States, the greater sensitivity of the technology in comparison to conventional imaging poses challenges for clinical trials. The NCI Clinical Imaging Steering Committee (CISC) PSMA PET Working Group was convened to coordinate the identification of these challenges in various clinical scenarios and to develop consensus recommendations on how best to integrate PSMA PET into ongoing and upcoming National Clinical Trials Network (NCTN) trials. METHODS NCI CISC and NCI Genitourinary Steering Committee members and leadership nominated clinicians, biostatisticians, patient advocates, and other imaging experts for inclusion in the PSMA PET Working Group. From April to July 2021, the working group met independently and in conjunction with the CISC to frame challenges, including stage migration, response assessment, trial logistics, and statistical challenges, and to discuss proposed solutions. An anonymous, open-ended survey was distributed to members to collect feedback on challenges faced. Representatives from each NCTN group were invited to present an overview of affected trials. From these discussions, the consensus document was developed and circulated for the inclusion of multiple rounds of feedback from both the Working Group and CISC. RESULTS The current consensus document outlines the key challenges for clinical prostate cancer trials resulting from the increasing availability of PSMA PET. We discuss implications for patient selection and definition of end points and provide guidance and potential solutions for different clinical scenarios, particularly with regard to best practices in defining eligibility criteria and outcome measures. RECOMMENDATIONS This article provides guidance regarding clinical trial design and conduct, and the interpretation of trial results.

PurposeAs prostate-specific membrane antigen (PSMA) positron emission tomography (PET) becomes increasingly available in the United States, the greater sensitivity of the technology in comparison to conventional imaging poses challenges for clinical trials. The NCI Clinical Imaging Steering Committee (CISC) PSMA PET Working Group was convened to coordinate the identification of these challenges in various clinical scenarios and to develop consensus recommendations on how best to integrate PSMA PET into ongoing and upcoming National Clinical Trials Network (NCTN) trials.MethodsNCI CISC and NCI Genitourinary Steering Committee members and leadership nominated clinicians, biostatisticians, patient advocates, and other imaging experts for inclusion in the PSMA PET Working Group. From April to July 2021, the working group met independently and in conjunction with the CISC to frame challenges, including stage migration, response assessment, trial logistics, and statistical challenges, and to discuss proposed solutions. An anonymous, open-ended survey was distributed to members to collect feedback on challenges faced. Representatives from each NCTN group were invited to present an overview of affected trials. From these discussions, the consensus document was developed and circulated for the inclusion of multiple rounds of feedback from both the Working Group and CISC.ResultsThe current consensus document outlines the key challenges for clinical prostate cancer trials resulting from the increasing availability of PSMA PET. We discuss implications for patient selection and definition of end points and provide guidance and potential solutions for different clinical scenarios, particularly with regard to best practices in defining eligibility criteria and outcome measures.RecommendationsThis article provides guidance regarding clinical trial design and conduct, and the interpretation of trial results.

ObjectivesThis study compared the relative prognostic utility of the Gross Tumor Volume (GTV), maximum Standardized Uptake Value (SUVmax), and Metabolic Tumor Volume (MTV) in a uniform cohort of oropharyngeal squamous cell carcinoma (OPSCC) patients treated with platinum-based concurrent chemoradiation therapy (CCRT).Methods and materialsOne-hundred OPSCC with a pretreatment [(18)F] fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) were treated with CCRT. Kaplan-Meier curves and Cox proportional hazard models were generated.ResultsWhen dichotomized by the median, a smaller MTV correlated with improved 5year locoregional control (LRC) (98.0% versus 87.0%, p=0.049), freedom from distant metastasis (FDM) (91.7% versus 65.0%, p=0.005), progression-free survival (PFS) (80.3% versus 56.7%, p=0.015), and overall survival (OS) (84.1% versus 57.8%, p=0.008), whereas a smaller GTV correlated with improved PFS (80.3% versus 57.4%, p=0.040) and OS (82.1% versus 60.1%, p=0.025). SUVmax failed to correlate with any outcome. On multivariate analysis, when adjusted for GTV, T-stage, and N-stage a smaller MTV remained independently correlated with improved FDM, PFS, and OS. GTV failed to reach significance in the multivariate model.ConclusionsA smaller MTV correlates with improved LRC, FDM, PFS, and OS in OPSCC patients undergoing platinum-based CCRT.

Background: Hypoxia within solid tumors confers radiation resistance and a poorer prognosis. 124I-iodoazomycin galactopyranoside (124I-IAZGP) has shown promise as a hypoxia radiotracer in animal models. We performed a clinical study to evaluate the safety, biodistribution, and imaging characteristics of 124I-IAZGP in patients with advanced colorectal cancer and head and neck cancer using serial positron emission tomography (PET) imaging. Methods: Ten patients underwent serial whole-torso (head/neck to pelvis) PET imaging together with multiple whole-body counts and blood sampling. These data were used to generate absorbed dose estimates to normal tissues for 124I-IAZGP. Tumors were scored as either positive or negative for 124I-IAZGP uptake. Results: There were no clinical toxicities or adverse effects associated with 124I-IAZGP administration. Clearance from the whole body and blood was rapid, primarily via the urinary tract, with no focal uptake in any parenchymal organ. The tissues receiving the highest absorbed doses were the mucosal walls of the urinary bladder and the intestinal tract, in particular the lower large intestine. All 124I-IAZGP PET scans were interpreted as negative for tumor uptake. Conclusions: It is safe to administer 124I-IAZGP to human subjects. However, there was insufficient tumor uptake to support a clinical role for 124I-IAZGP PET in colorectal cancer and head and neck cancer patients. Trial registration: ClinicalTrials.gov NCT00588276