Histiocytosis
Conditions
Keywords
histiocytosis, 68Ga-FAPI, PET/CT
Brief summary
Histiocytic disorders are rare diseases that are characterized by tissue infiltration of histiocytes (dendritic cells) and other inflammatory white blood cells.68Ga-FAPI has been developed as a tumor-targeting agent as fibroblast activation protein is overexpressed in cancer-associated fibroblasts and it might be a pan-tumor PET agent.Recent discoveries have shown that inflammation and fibrosis secondary to mutated histiocytes, rather than a proliferative cell mechanism, result in manifestation of the disease.Thus, the investigators aim to carry out this prospective study to investigate the role of 68Ga-FAPI PET/CT in the diagnosis, therapy response assessment and follow-up of histiocytosis.
Detailed description
Histiocytic disorders are rare diseases that are characterized by tissue infiltration of histiocytes (dendritic cells) and other inflammatory white blood cells. The archaic term histiocyte refers to large white blood cells resident in tissues and includes Langerhans cells, monocytes/macrophages, and dermal/interstitial dendritic cells. The Histiocytic Society classification divides histiocytic disorders into five categories, based on clinical, histologic, immunophenotypic, and molecular features. They are langerhans (L) group, cutaneous and mucocutaneous (C) group, Rosai-Dorfman disease (R) group, malignant histiocytosis (M) group and hemophagocytic lymphohistiocytosis (H) group. Langerhans cell histiocytosis is the most common histiocytic disorder. Less common types include Erdheim-Chester disease, Rosai-Dorfman disease, adult and juvenile xanthogranuloma. Diagnosis, which relies on a multidisciplinary approach, is challenging and often delayed because clinical findings are nonspecific and may mimic malignant processes at radiologic evaluation. Compared with conventional imaging, PET/CT allows detection of the increased metabolic activity in histiocytes and provides a comprehensive whole-body evaluation of their potential involvement with multiple organ systems and allows monitoring of therapeutic response. However, one drawback is that the uptake of FDG is nonspecific because histiocytic lesions may mimic neoplastic processes at PET/CT. And the physiological FDG metabolism in brain, liver and gastrointestinal tract, et al. hampers the detection rate of lesions located in these organs.68Ga-FAPI has been developed as a tumor-targeting agent as fibroblast activation protein is overexpressed in cancer-associated fibroblasts and it might be a pan-tumor PET agent. Although the pathogenesis of histiocytosis may be attributable to mutations in the oncogenic driver, recent discoveries have shown that inflammation and fibrosis secondary to mutated histiocytes, rather than a proliferative cell mechanism, result in manifestation of the disease. Considering 68Ga-FAPI revealing cancer-associated fibroblasts, the investigators aim to carry out this prospective study to investigate the role of 68Ga-FAPI PET/CT in the diagnosis, therapy response assessment and follow-up of histiocytosis.
Interventions
DIAGNOSTIC_TEST68Ga-FAPI
Intravenous injection of one dosage of 74-148 MBq(2-4 mCi) 68Ga-FAPI.
DIAGNOSTIC_TEST18F-FDG
Intravenous injection of one dosage of 7.4MBq/kg(0.2mCi/kg) 18F-FDG. 18F-FDG PET/CT is performed within one week from 68Ga-FAPI PET/CT scan.
Sponsors
Peking Union Medical College Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 90 Years
Healthy volunteers
No
Inclusion criteria
* suspected or confirmed untreated histiocytosis patients * 18F-FDG PET/CT within two weeks; * signed written consent.
Exclusion criteria
* pregnancy; * breastfeeding; * known allergy against FAPI
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Diagnostic value | through study completion, an average of 1 year | Sensitivity and Specificity of 68Ga-FAPI PET/CT for histiocytosis in comparison with 18F-FDG PET/CT |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Metabolic parameters | through study completion, an average of 1 year | Total Lesion Glycolysis (TLG) of histiocytosis lesions are measured on 68Ga-FAPI PET/CT. |
| FAPI expression and SUV | through study completion, an average of 1 year | Correlation between FAPI expression and SUV in PET |
| Disease burden assessement | through study completion, an average of 1 year | Correlation between Total Lesion Glycolysis (TLG) of histiocytosis lesions assessed on 68Ga-FAPI PET/CT and clinical parameters for histiocytosis |
| therapy response | through study completion, an average of 1 year | Decrease of Total Lesion Glycolysis (TLG) on 68Ga-FAPI PET/CT after therapy |
Countries
China
Contacts
Primary ContactYaping Luo, MD
Backup ContactQingqing Pan, MD
Outcome results
None listed