| Abstract: |
Gastric cancer is the most common gastrointestinal malignancy worldwide, accounting for about 8.6% of new cancer cases worldwide. Although the overall incidence of stomach cancer is declining, in the USA about 21,000 new cases have been diagnosed in 2010 (~1.4% of all cancers), and about 10,570 will die. The depth of cancer invasion through the gastric wall and the number of involved lymph nodes are directly related to prognosis. After primary diagnosis, the lesion is staged according to the American Joint Committee on Cancer (AJCC). Esophagogastroduodenoscopy combined with endoscopic biopsy, endoscopic ultrasonography, and CT. Ultrasounds have the best accuracy for T and N classification, while CT is especially useful for M classification. [18F]FDG-PET is not an effective screening tool for the diagnosis of gastric cancer. Sensitivity of [18F]FDG-PET imaging in detecting primary gastric lesions is influenced by tumor size and T stage (21% tumors <30 mm, 76% for lesions over 30 mm). Histological subtype variants also influence glucose uptake (greater for intestinal than non-intestinal type). In an effort to improve detection of gastric cancer by PET, 3 ¢ -deoxy-3 ¢ - 18 F-fluorothymidine (18 F-FLT) has been used as an alternative radiotracer to [18F]FDG. Sensitivity of [18F]FDG-PET is generally low for the detection of lymph node metastases ranging from 22% to 60%, although the specificity of PET is higher than that of CT. Moreover, PET is not a reliable indicator of peritoneal disease with a sensitivity <50%. When compared to contrast CT, PET showed a nonsignificant trend toward decreased sensitivity and increased specificity in the detection of recurrent disease. The advantage of PET over CT mainly regards the assessment of therapy response (neoadjuvant or perioperative chemotherapy). Moreover, metabolic response appeared to correlate significantly with survival. © Springer Science+Business Media New York 2013. All rights are reserved. |
