The Clinical Value of 18F-fluorodeoxyglucose Uptake on Positron Emission Tomography/computed Tomography for Predicting Regional Lymph Node Metastasis and Non-curative Surgery in Primary Gastric Carcinoma

Background/aims: Accurate preoperative detection of regional lymph nodes and evaluation of tumor resectability is critical to determining the most adequate therapy for gastric cancer. The aim of this study is to identify a possible link between 18F-fluorodeoxyglucose (18F-FDG) uptake on PET scan combined with CT scan (PET/CT) and predictions of lymph node metastasis and non-curative surgery.

Methods: This study included 156 gastric cancer patients who underwent preoperative 18F-FDG PET/CT and surgery. In cases with perceptible FDG uptake in the primary tumor or lymph nodes, the maximum standardized uptake value (SUVmax) was calculated.

Results: In multivariate analysis, non-curative surgery (OR, 11.05; 95% CI, 1.10-111.08; p=0.041), tumor size (≥3 cm) (OR, 7.39; 95% CI, 2.41-22.70; p<0.001), and lymph node metastasis (OR, 5.47; 95% CI, 2.05-14.64; p=0.001) were significant independent predictors for 18F-FDG uptake in the primary tumors. Tumor size (tumor size ≥3 cm) (OR, 3.15; 95% CI, 1.16-8.58; p=0.025) and lymph node metastasis (OR, 3.36; 95% CI, 1.23-9.14; p=0.018) showed significant association with 18F-FDG uptake in lymph node. When the SUVmax of the primary gastric tumor was greater than 3.75, the sensitivity and specificity of PET/CT with regard to the diagnosis of metastatic lymph node were 73.5% and 74.5%. When the SUVmax of the primary gastric tumor was greater than 4.35 and the FDG uptake of lymph nodes was positive, non-curative surgery was predicted with a sensitivity of 58.8% and specificity of 91.6%.

Conclusions: A high FDG uptake of the gastric tumor was related to histologic positive lymph nodes and non-curative surgery.