Akademik Veri Yönetim Sistemi
12th Balkan Congress of Nuclear Medicine, Athens, Yunanistan, 08 Mayıs 2025, ss.72, (Tam Metin Bildiri)
Objective: This study aims to evaluate the relationships between preoperative 18F-FDG PET/CT parameters, histopathologic findings, biomarkers and radiomic analysis and to contribute to the literature.
Methods: A total of 357 patients with gastric cancer admitted to the Nuclear Medicine Clinic between January 2015 and January 2020 were retrospectively analyzed. Forty-three patients with preoperative PET/CT and available histopathologic data and biochemical parameters were included in the study. Tumor size, lymphovascular, perineural and vascular invasion findings, HER2 (Human Epidermal Growth Receptor 2), PD-L1 (Programmed Cell Death Ligand 1) and MSI (Microsatellite Instability) results obtained from histopathological reports were recorded. In PET/CT analysis, tumor size, localization and tumor SUVmax, SUVmean, MTV and TLG values were determined.In addition, CEA, CA19-9, CA125, C15-5 tumor markers of the patients were included in the study.
In addition, heterogeneity analysis of the primary tumor was performed with LIFEX 7.7.0 application and radiomic features were evaluated.Radiomic analysis helps to quantify the intra-tissue differences, metabolic activity distribution and structural irregularities of the tumor.
Results: Of the 43 patients with gastric adenocarcinoma included in the study, 34 were male and 9 were female. In all patients, the primary lesion showed markedly increased uptake on PET/CT. At the same time, SUVmax and SUVmean values were statistically significantly higher in cardia tumors (p<0.001 and p=0.002). When the data obtained from LİFEx7.7.0 application were examined, GLCM_JointMaximum (0.0078), GLCM_DifferenceAverage (6.8028) and GLRLM_ShortRunsEmphasis (0.9774) values were significantly higher in cardia tumors compared to tumors in other localizations (p=0.028, p=0.002, p=0.005). HER2 expression was significantly higher in the cardia localization (p=0.013), but no significant correlation was found with PD-L1 and MSI.
Conclusion: In this study, we evaluated the relationships between preoperative 18F-FDG PET/CT parameters, histopathologic features, biomarkers and radiomic analysis results in patients with gastric cancer. Higher metabolic activity and tissue heterogeneity in cardia tumors suggest that these tumors may be more aggressive. Furthermore, a significant difference was found in HER2 expression in cardia tumors. This finding suggests that HER2 expression may play an important role in treatment approaches and that the biological characteristics of cardia tumors are more aggressive and further studies involving large patient groups are necessary.