Value of Preoperative PET-CT in the Prediction of Pathological Stage of Gastric Cancer

Michihiro Kudou, Toshiyuki Kosuga, Takeshi Kubota, Kazuma Okamoto, Shuhei Komatsu, Katsutoshi Shoda, Hirotaka Konishi, Atsushi Shiozaki, Hitoshi Fujiwara, Tomohiro Arita, Ryo Morimura, Yasutoshi Murayama, Yoshiaki Kuriu, Hisashi Ikoma, Masayoshi Nakanishi, Eigo Otsuji

Preoperative precise staging is essential for the treatment of gastric cancer (GC); however, the diagnostic accuracy of conventional modalities needs to be increased. The present study investigated the clinical value of positron emission tomography-computed tomography (PET-CT) for the staging of GC. This was a retrospective study of 117 patients with a clinical diagnosis of advanced GC who underwent PET-CT followed by gastrectomy. The incidence of FDG uptake in the primary tumor or lymph nodes and its relationship with clinicopathological factors, particularly pathological stage (pStage) III/IV, were examined. FDG uptake in the primary tumor was noted in 83 patients (70.9%). FDG uptake in the lymph nodes was detected in 21 patients (17.9%), and its sensitivity and specificity for lymph node metastasis were 22.7 and 90.5%, respectively. Multiple logistic regression analyses showed that FDG uptake in the primary tumor (odds ratio (OR) 2.764; 95% confidence interval (CI) 1.104-7.459, p = 0.029) and that in the lymph nodes (OR 4.660; 95% CI 1.675-13.84, p = 0.003) were factors independently associated with pStage III/IV. FDG uptake in the primary tumor detected pStage III/IV with higher sensitivity (80.4%) and that in lymph nodes found pStage III/IV with higher specificity (88.7%) than those of upper endoscopy plus CT (60.9 and 67.6%, respectively). PET-CT appears to be a useful complementary modality in the assessment of pStage III/IV because of the high sensitivity of FDG uptake in the primary tumor and the high specificity of FDG uptake in the lymph nodes.