An interventional study of PET/MRI with 18F-FDG and [68Ga]Ga-CTR-FAPI in Rectal Cancer, Lymph Node Metastases and PET / MR, sponsored by Peking University Cancer Hospital & Institute. Not yet recruiting. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-05-04.
Sponsored by Peking University Cancer Hospital & Institute · Not applicable, Interventional, and Diagnostic
This is a prospective, single-center, diagnostic study designed to compare the accuracy of [68Ga]Ga-CTR-FAPI PET/MRI and [18]F-FDG PET/MRI for the detection of lymph node metastasis in patients with initially untreated, resectable middle to high rectal cancer. The study aims to evaluate whether [68Ga]Ga-CTR-FAPI PET/MRI provides higher sensitivity and specificity than traditional 18F-FDG PET/MRI at both the patient level and the lymph node level.
Accurate preoperative staging of colorectal cancer is crucial for formulating treatment plans and improving patient prognosis. While conventional MRI and 18F-FDG PET/MRI are utilized, they face limitations such as false positives due to inflammatory lymph nodes or fibrotic scars. Fibroblast activating protein inhibitor (FAPI) specifically targets tumor-associated fibroblasts, potentially reducing false-positive rates by avoiding non-specific uptake in inflammatory areas.
This study aims to cross-validate the diagnostic efficacy of these two probes through a precise imaging-pathology matching technique. All enrolled patients will sequentially undergo both [68Ga]Ga-CTR-FAPI PET/MRI and 18F-FDG PET/MRI within 30 days prior to radical surgery. Following surgery, fresh mesorectal specimens will be precisely sectioned and matched to preoperative anatomical imaging maps. By leveraging a well-established node-by-node matching and identification methodology with high accuracy, this study ensures the execution of spatial correlation between preoperative radiologic imaging and postoperative microscopic pathology. Through mapping individual lymph nodes, the study will analyze the root causes of false positives and negatives, and extract radiomics features to evaluate their correlation with the tumor microenvironment (e.g., fibroblast density, Ki-67 index).
1,761 studies on the registry are indexed under Rectal Neoplasms; 518 are open to participants now.
This study's planned enrollment of 30 is below the median of 65 across 1,297 interventional studies indexed under Rectal Neoplasms.
Browse Rectal Neoplasms studies →Peking University Cancer Hospital & Institute is the lead sponsor of 261 studies on the registry; 128 are open to participants now.
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Exclusion Criteria:
Patients with confirmed middle to high rectal adenocarcinoma who are scheduled for radical surgery.
Diagnostic Test: PET/MRI with 18F-FDG and [68Ga]Ga-CTR-FAPI
Diagnostic Test: 18F-FDG PET/MRI Description: Patients receive an intravenous injection of 18F-FDG (3.7-5.5 MBq/kg). Diagnostic Test: \[68Ga\]Ga-CTR-FAPI PET/MRI Description: Patients receive an intravenous injection of \[68Ga\]Ga-CTR-FAPI (1.8-3.7 MBq/kg).
Sensitivity and Specificity of Lymph Node Metastasis Detection
Comparison of the sensitivity and specificity of \[68Ga\]Ga-CTR-FAPI and 18F-FDG PET/MRI in determining lymph node metastasis at both the individual lymph node level and the patient level. Sensitivity is defined as the proportion of imaging-positive and pathology-positive nodes out of all pathology-positive nodes. Specificity is defined as the proportion of imaging-negative and pathology-negative nodes out of all pathology-negative nodes.
Time frame: Up to 30 days post-surgery
False Positive and False Negative Rates
Analysis of the false positive and false negative rates of FAPI and FDG imaging, exploring underlying pathological bases such as inflammation or micrometastasis.
Time frame: Up to 30 days post-surgery
Correlation Between Radiomics Features and Tumor Microenvironment
Extraction of lymph node radiomics features to evaluate their association with tumor microenvironmental markers, determined via automatic immunohistochemistry scoring.
Time frame: Up to 30 days post-surgery
No study locations are listed for this record.
Plan to share: No
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This study is not yet recruiting, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Peking University Cancer Hospital & Institute