Exploring the Novel Value of PSMA PET in Sjögren's Syndrome: Integrated Analysis With Established FAPI PET Imaging
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: ⁶⁸Ga-PSMA PET/CT, ⁶⁸Ga-FAPI PET/CT.
- Who it may be relevant to
- Registry conditions: Primary Sjögren Syndrome, PET. Basic parameters: 18 years — 80 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- China
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
Primary Sjögren's syndrome (pSS) is a chronic autoimmune exocrinopathy characterized by lymphocytic infiltration, progressive destruction of salivary gland acini, and varying degrees of functional impairment and fibrosis. Conventional imaging provides limited ability to simultaneously evaluate glandular function and inflammatory activity, leading to challenges in disease staging and treatment decision-making. This study explores a conceptual dual-tracer imaging framework using PSMA PET and FAPI PET to delineate complementary biological processes in pSS.
Detailed description
Based on current evidence, salivary gland acinar cells physiologically express PSMA; thus, reduced PSMA uptake may reflect loss of functional parenchyma in patients with pSS. In contrast, activated fibroblasts markedly express FAP, and increased FAPI uptake correlates with ongoing inflammation and fibroblast-driven remodeling. We hypothesize that within the same gland, functional decline (PSMA↓) and inflammatory activity (FAPI↑) may coexist and exhibit a negative correlation, forming a paired imaging biomarker that captures both pathological dimensions. By integrating these two signals into a combined PSMA/FAPI Index, this approach may enable more precise characterization of the "function-inflammation" spectrum in pSS, providing a noninvasive tool for disease staging, monitoring, and potentially predicting therapeutic response.
Interventions
- Diagnostic test ⁶⁸Ga-PSMA PET/CT
PSMA PET imaging performed for clinical evaluation in prostate cancer patients, used as a comparator for physiologic salivary gland PSMA uptake. - Diagnostic test ⁶⁸Ga-FAPI PET/CT
FAPI PET imaging to assess inflammatory activity (FAPI) in patients with primary Sjögren's syndrome.
Primary outcome measures
- Difference in Salivary Gland PSMA Uptake Across Groups [Time frame: Baseline]
Secondary outcome measures (3)
- Multiglandular PSMA Uptake Comparison [Time frame: Baseline]
- Correlation Between PSMA Uptake and Clinical Indicators [Time frame: Baseline]
- Quantitative and Spatial Relationship Between PSMA and FAPI Uptake Definition [Time frame: Baseline]
Eligibility criteria
Inclusion criteria
- Age 18-80 years;
- Fulfillment of the 2016 ACR-EULAR Classification Criteria for pSS at enrollment. OR diagnosis of a solid tumor scheduled for FAPI PET imaging
Exclusion criteria
- Combined with tumors or other connective tissue diseases (for SS group);
- Patients who are currently using hormones/biological agents (for both groups)；
- Pregnancy or lactation
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Non-randomized
- Model
- Parallel assignment
- Masking
- Open label
- Primary purpose
- Diagnostic
Study locations
China · 1 center
- Peking Union Medical College Hospital — Beijing
Identifiers
NCT: NCT07324733 · PUMCH-PSS-PSMA