The Diagnostic Accuracy and Clinical Value of FAPI PET in Pleural Mesothelioma (FAPI-PM)

Primary Outcome Measures

• Calculate the proportion of patients where the location of the intended pleural biopsy is altered due to FAPI PET/CT replacing FDG PET/CT.

Secondary Outcome Measures

• Compare the cancer stage (IASCL 9th edition TNM-classification) as determined by FAPI PET/CT compared to conventional imaging (including FDG PET/CT) at primary staging.
• Calculate the proportion of patients with suspected PM lesion with a change in treatment following the -hypothetical – addition of FAPI PET/CT at primary staging.
• Investigate the FAPI PET uptake parameters in suspicious PM lesions (primary tumor), regional lymph nodes, and distant metastases, and in benign lesions. Correlate FAPI uptake parameters in different PM subtypes.
• Calculate changes in FAPI PET uptake parameters – from before to after 2-3 series of anticancer treatment. Changes will be presented as ratios and in %.
• Correlate the FAPI PET SUV to FAP targeting immunohistochemistry of biological material.
• Seek supplementary information in medical records, biochemistry, pathology, or other imaging modalities for a final diagnosis/condition in cases of unexpected FAPI PET/CT findings.
• Report Incidence Treatment-Emergent Adverse Events
• A 10 year follow up of included patients will be conducted to determine overall survival (OS) in days from diagnosis, correlated to FAPI PET/CT results.
• A 10 year follow up of included patients will be conducted to determine Recurrence Free Survival (RFS) and Progression Free Survival (PFS) in days from diagnosis, correlated to FAPI PET/CT results.
• Compare conventional CT-based response assessment (mRECIST/iRECIST) to PET based response assessment (PERCIST, and other FDG and FAPI PET derived data) to the clinical outcome, i.e., OS, RFS/PFS.
• Conduct an interobserver study of FAPI PET/CTs. Cohens Kappa d will be calculated.

Inclusion Criteria

• Patients with pleural lesions suspicious of pleural mesothelioma and referred to pleural biopsy.
• Undergone/undergoing FDG PET/CT as part of the diagnostic workup of a suspicious PM lesion.
• Considered physically and mentally able to participate in the research project.
• Understands the study subject information and able to consent to project participation.
• 18-years or older

Exclusion Criteria

• Patients with an imminent need for surgery or in an emergency
• Known concurrent other malignancy with active treatment within the last 1 year; non-melanoma skin cancer and cervical cancer in situ are exempt.
• Pregnant or breastfeeding women.
• Fertile women (women of childbearing potential) who could – theoretically – be pregnant (i.e., unknown pregnancy status).