This trial studies how well 68Ga-PSMA-11 PET scan works in imaging patients with prostate cancer. Diagnostic procedures, such as 68Ga-PSMA-11 PET may find and diagnose prostate cancer and improve monitoring of treatment response.
OUTLINE: Patients receive gallium Ga 68-labeled PSMA-11 intravenously (IV) over 60-75 minutes then undergo PET/CT or PET/magnetic resonance (MR) scan over 2-4 minutes per bed position at baseline. Patients receiving systemic therapy undergo an additional 68Ga-PSMA-11 PET/CT or PET/MR scan 12 weeks after initiating therapy. Patients may also undergo CT and bone scan during screening and on study. After the completion of study, patients are followed up at 60 days, 6 months, and annually up to 5 years or until time of first progression.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
141
Undergo PET/CT scan
Given IV
Undergo PET/CT scan
Undergo PET/MR scan
Undergo bone scan
Ancillary studies
Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington, United States
Change in planned management strategy
Assessed using conventional imaging with executed management strategy incorporating information from first (scan 1) 68Ga-prostate-specific membrane antigen (PSMA)-11 positron emission tomography (PET)/computed tomography (CT), regardless of treatment modality. Will be expressed as the percentage of total patients imaged in which change in management occurred, regardless of treatment modality. The rate of change in management will also be estimated within each group (initial staging, biochemical recurrence, and equivocal lesion cohorts). 95% confidence intervals (CIs) will be used to express precision of the estimates.
Time frame: Baseline up to 1.5 years after the last scan
Major change in management
Defined as a change in treatment modality (e.g. change from systemic therapy to radiation therapy). Will compare by planned management strategy using conventional imaging and executed management strategy incorporating information from scan 1 68Ga-PSMA-11 PET/CT, regardless of treatment modality. 95% CIs will be used to express precision of the estimates. This analysis applies to the subjects enrolled in the initial staging (N=30), biochemical recurrence (N=30), and equivocal lesions cohorts (N=43).
Time frame: Baseline up to 5 years post-scan
Minor change in management
Defined as changes within a treatment modality (e.g. change in planned radiation field or change in systemic therapy regimen to be used for a patient already planned to receive systemic therapy). Defined as a post-scan change within a treatment modality (e.g. alteration to salvage radiation field). 95% CIs will be used to express precision of the estimates.
Time frame: Baseline up to 5 years post-scan
68Ga-PSMA-11 standardized uptake value maximum (SUVmax)
Changes in uptake will be compared among all groups using analysis of variance (ANOVA) or the Kruskal-Wallis test and between pairs of groups using the t-test or Wilcoxon rank-sum test.
Time frame: Up to 6 weeks after systemic therapy initiation
68Ga-PSMA-11 standard uptake value normalized to lean body mass (SULpeak)
Changes in uptake will be compared among all groups using ANOVA or the Kruskal-Wallis test and between pairs of groups using the t-test or Wilcoxon rank-sum test.
Time frame: Up to 6 weeks after systemic therapy initiation
Change in 68Ga-PSMA-11 SUVmax
Expressed as percent (%) change from scan 1. Will be determined and correlated with change in prostate specific antigen (PSA) level and Response Evaluation Criteria in Solid Tumors (RECIST) for measurable lesions, as assessed using Pearson's or Spearman's correlation coefficient. The relationship of changes in SUVmax and SULpeak with clinical response categories will also be assessed graphically and summarized overall with Spearman's rank correlation coefficient. Clinical response categories will be defined as complete response, partial response, stable disease, and progressive disease and determined by clinical assessment, conventional imaging, and biopsy (if available). The subgroup analysis of this group will be exploratory. Changes in uptake will be compared among all groups using ANOVA or the Kruskal-Wallis test and between pairs of groups using the t-test or Wilcoxon rank-sum test.
Time frame: Baseline up to 6 weeks after systemic therapy initiation
Change in 68Ga-PSMA-11 SULpeak
Expressed as percent (%) change from scan 1. Will be determined and correlated with change in prostate specific antigen (PSA) level and Response Evaluation Criteria in Solid Tumors (RECIST) for measurable lesions, as assessed using Pearson's or Spearman's correlation coefficient. The relationship of changes in SUVmax and SULpeak with clinical response categories will also be assessed graphically and summarized overall with Spearman's rank correlation coefficient. Clinical response categories will be defined as complete response, partial response, stable disease, and progressive disease and determined by clinical assessment, conventional imaging, and biopsy (if available). The subgroup analysis of this group will be exploratory. Changes in uptake will be compared among all groups using ANOVA or the Kruskal-Wallis test and between pairs of groups using the t-test or Wilcoxon rank-sum test.
Time frame: Baseline up to 6 weeks after systemic therapy initiation
Change in size of measurable metastatic lesions
Assessed by CT or magnetic resonance imaging (MRI) by RECIST 1.1 criteria.
Time frame: Baseline up to 5 years post-scan
Histopathologic demonstration of prostate cancer within biopsy or surgical resection specimens
Will be performed only in patients with biopsy or surgical resection specimens. Lesions on each scan will be categorized as positive or negative. Pathology results will also be scored as positive or negative based on the clinical interpretation. These results will then be used to calculate accuracy with 95% CIs. CIs will be calculated using the non-parametric bootstrap with resampling by patient to account to dependence between lesions from the same patient.
Time frame: Up to 5 years post-scan
Change in PSMA total tumor volume
Response defined by RECIST 1.1 criteria.
Time frame: Baseline up to 5 years post-scan
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