FAPI PET/CT Prospective Interobserver Agreement (AGREE-FAPI)

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

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.

Study Overview

• Status: Completed
• Conditions: Malignant Neoplasm
• Intervention / Treatment: Other: Interpretation of FAPI-PET/CT scans

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 15

Contacts and Locations

Study Locations

• Germany
  • Essen, Germany
    • Department of Nuclear Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Each recruited observer will be asked to review 50 68Ga-FAPI PET/CT scans of patients with different types of tumor.

Observers will be blinded to clinical data except of the following patient information: sex, age (years), weight (Kg), injected dose (MBq), uptake time (min), type of cancer and PET/CT indication (e.g. staging, re-staging after surgery, evaluation after therapy).

Each observer will be also asked to record maximum standardized uptake value (SUVmax) for one exemplary lesion for each tissue (organ, node, bone).

Description

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.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Low Experience Group; 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; Each observer's Group will be asked to review FAPI-PET/CT scans of patients with representative cancer types.
Intermediate Experience Group; 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; Each observer's Group will be asked to review FAPI-PET/CT scans of patients with representative cancer types.
High Experience Group; 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; Each observer's Group will be asked to review FAPI-PET/CT scans of patients with representative cancer types.

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: University Hospital, Essen
• Investigators: Principal Investigator: Wolfgang Fendler, MD, Study Principal Investigator

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2021
• Primary Completion (Actual): October 30, 2022
• Study Completion (Actual): October 30, 2022

Study Registration Dates

• First Submitted: July 16, 2021
• First Submitted That Met QC Criteria: July 26, 2021
• First Posted (Actual): August 5, 2021

Study Record Updates

• Last Update Posted (Actual): November 3, 2022
• Last Update Submitted That Met QC Criteria: November 1, 2022
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Keywords: imaging; cancer; PET; FAP; FAPI; Positron-Emission-Tomography; fibroblast; Interobserver agreement
• Additional Relevant MeSH Terms: Neoplasms
• Other Study ID Numbers: AGREE-FAPI

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No