The Relationship of SUV Value in PET-CT with Tumor Differentiation and Tumor Markers in Gastric Cancer

Abstract

Objective: We aimed to investigate the relationship between the use of fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT), maximized standardized uptake value(SUVmax) values of tumors, and tumor differentiation and tumor markers during the initial staging of patients with gastric cancer.Materials and Methods: The study included 50 patients (14 women and 36 men; mean age: 63±11 years;age range: 31-80 years) who had undergone initial staging with FDG-PET/CT after the diagnosis of gastriccancer with endoscopic biopsy between January and June 2013. Serum alpha fetoprotein (AFP), carcinogenicantigen 19-9 (CA 19.9), carcinoembryonic antigen (CEA), and C-reactive protein (CRP) levels were measured in patients prior to imaging. PET/CT images were evaluated for primary tumors, locoregional spread,and distant organ metastases, and classified by tumor-node-metastasis staging. Semiquantitative data werecollected by SUVmax measurements in pathological regions of involvement. Data were analyzed statistically.Results: FDG-PET/CT showed primary gastric cancer with a sensitivity of 87%. Imaging findings were normalin 3 patients (1/3; mucinous adenocarcinoma, 2/3; signet-ring cell adenocarcinoma). With FDG-PET/CT, 3/50patients were classified into Stage 1B, 3/50 patients into Stage 2, 5/50 patients into Stage 3A, 5/50 patientsinto Stage 3B, 5/50 patients into 3C and 29/50 patients into Stage 4. The mean SUVmax was calculatedas 11.35±4.3 (poorly differentiated adenocarcinoma: 5.4±1.7; moderately differentiated adenocarcinoma:10.3±4.8) for the primary tumor and 14.9±6.3 for tumor metastasis. A positive correlation was evidentbetween the measured SUVmax and stage and the grade of primary tumor (p