18F-FDG PET/MRI versus PET/CT in staging Gastro-Esophageal Junction cancer

none9siPurpose: To compare F-18-Flurodeoxyglucose(FDG)-positron-emission-tomography/magnetic-resonance-imaging(PET/MRI) and PET/computed-tomography(PET/CT) in staging of gastro-esophageal junction(GEJ) cancer. Materials and Methods: Following IRB approval and informed consent, 24 patients with histologically proven GEJ cancer were prospectively recruited; 4 patients were excluded for technical reasons (19 male, 1 female; mean 68.3 +/- 9.1 years). Patients were injected with 326+/-28 MBq F-18-FDG intravenously for the clinical PET/CT. Uptake time was 60 minutes. PET/MRI was acquired directly after the PET/CT. 2 experienced radiologists and nuclear physicians reviewed the images and defined the PET/MRI-TNM stage in consensus. PET/CT NM-stage was defined clinically. They were compared to the multidisciplinary team meeting(MDT) stage, which was defined by contrast enhanced CT+/-endoscopic ultrasonography(EUS). Sensitivity(SE), Specificity(SP), positive predictive value(PPV), negative predictive value(NPV) and accuracy(AC) were calculated. McNemar test was performed to assess differences between different modalities. Results: For PET/MRI T-stage was concurred with MDT stage in 14 (70%) of 20 patients. Differences in T-stages between PET/MRI and MDT were statistically significant (p=0.03) (Table1). In our cohort, PET/MRI upstaged three T3 primary lesions as T4 and correctly assigned two T4 lesions. Both PET/MRI and PET/CT agreed in N-and M-staging in all patients. Differences in N-stage between hybrid modalities and MDT were significant (p=0.03) (6 of 20 patients) (Table2). SE, SP, PPV, NPV and AC for detection of lymph node metastases were 94%, 100%, 100%, 67% and 95% for both imaging modalities. Conclusions: PET/MRI and PET/CT performed similarly in N and M staging. PET/MRI has advantages over PET/CT in providing additional T-stage. Clinical Relevance statement: PET/MRI might be used for staging of patients with cancer of GOJ in the future. Table 1: Differences in T-stage. PET/MRI MDT 3 4 4 3 2 3 4 3 4 3 2 3 4 4 Table 2: Differences in N-stage. PET/MRI PET/MRI MDT 2 2 1 0 0 1 2 2 1 2 2 3 2 2 3 1 1 2noneBert-Ram Sah, Serena Baiocco, Andrew Mallia, Christian Kelly-Morland, James Stirling, Sami Jeljeli, Alessandro Bevilacqua, Gary Cook, Vicky GohBert-Ram Sah, Serena Baiocco, Andrew Mallia, Christian Kelly-Morland, James Stirling, Sami Jeljeli, Alessandro Bevilacqua, Gary Cook, Vicky Go