FAPI PET/CT Prospective Interobserver Agreement

Study Overview
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Brief Summary
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The aim of the present study is to evaluate the interobserver agreement for FAPI PET/CT interpretations of representative cancer types and compare findings among readers with different levels of experience.

Detailed Description
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Fibroblast activation protein (FAP) is expressed by many cancer-associated fibroblasts, having a pivotal role in many desmoplastic tumor histotypes (sarcoma, pancreatic cancer, colorectal cancer). 68Ga-FAPI inhibitor (FAPI) is a promising novel molecular imaging tracer for positron emission tomography with computed tomography (PET/CT), with favorable initial results in different tumor entities. Compared to 18F-FDG, 68Ga-FAPI PET/CT shows a similar biodistribution, with less background tracer uptake in the brain, oral mucosa and liver, thus making this tracer potentially suitable to detect tumor lesions in these regions. Moreover, the FAPI ligand contains a DOTA peptide which makes it appropriate also for therapeutic options if linked with 177Lutetium or 90Yttrium. There is an increasing number of trials aimed to assess the efficacy and the clinical impact of 68Ga-FAPI PET/CT. Therefore, the inter-observer agreement and variability with 68Ga-FAPI PET/CT need to be established.

Official Title
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FAPI PET/CT Imaging for Cancer: A Prospective Interobserver Agreement Study

Conditions
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Malignant Neoplasm

Intervention / Treatment
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* Other: Interpretation of FAPI-PET/CT scans


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Nuclear medicine physicians or radiologists with a prior experience with 68Ga-FAPI PET/CT from high-volume centers (Essen, Germany; Bologna, Italy; Los Angeles, USA; Munich, Germany, Münster, Germany ) will be prospectively recruited as research observers. Each observer will be asked to report the number of previous clinical 68Ga-FAPI PET/CT scans and then will be classified on the basis of the experience in these three groups: Low experience (< 30 prior 68Ga-FAPI PET/CT studies); Intermediate experience (30 to 300 studies); High experience (> 300 studies) At least three observers will be needed for each group. Exclusion criteria: No prior PET/CT experience.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Low Experience Group<br>Nuclear medicine physicians or radiologists with a prior experience with 68Ga-FAPI PET/CT of less than 30 studies. | Other: Interpretation of FAPI-PET/CT scans<br>* Each observer's Group will be asked to review FAPI-PET/CT scans of patients with representative cancer types.<br>|
| Intermediate Experience Group<br>Nuclear medicine physicians or radiologists with a prior experience with 68Ga-FAPI PET/CT of more than 30 studies and less than 300 studies. | Other: Interpretation of FAPI-PET/CT scans<br>* Each observer's Group will be asked to review FAPI-PET/CT scans of patients with representative cancer types.<br>|
| High Experience Group<br>Nuclear medicine physicians or radiologists with a prior experience with 68Ga-FAPI PET/CT of more than 300 studies. | Other: Interpretation of FAPI-PET/CT scans<br>* Each observer's Group will be asked to review FAPI-PET/CT scans of patients with representative cancer types.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Agreement among observer groups in interpreting FAPI PET/CT scans | Number of concordant scans among observer groups. Each scan will be rated as positive, negative or suspicion. For each scan all definite and suspicious lesions will be reported as well. Observer's reports data will be compared with an Expert Reading, which includes lesion validation, if applicable (i.e. imaging, laboratory, histopathology). | 3 Months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Agreement among observer groups in interpreting TNM stage and semi-quantitative values. | Number of concordant scans for TNM staging and for semi-quantitative values among observer groups. For each scan all definite and suspicious lesions with uptake values will be reported and a post-analysis TNM staging will be performed. Observer's reports data will be compared with an Expert Reading, which includes lesion validation, if applicable (i.e. imaging, laboratory, histopathology). | 3 Months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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FAPI, cancer, Positron-Emission-Tomography, FAP, fibroblast, imaging, PET, Interobserver agreement