[The Role of Positron Emission Tomography in the Detection of Incidental Gastrointestinal Tract Lesions in Patients Examined for Lung Cancer]

The purpose of this study was to clarify the clinical characteristics of lung cancer patients with abnormal accumulation in the gastrointestinal tract by fluoro-2-deoxyglucose positron emission tomography (PET). Of the 968 consecutive patients with primary lung cancer who underwent PET from October 2005 through September 2009, 26 patients had local abnormal accumulation in the gastrointestinal tract. We retrospectively compared the localization of abnormal accumulation in the gastrointestinal tract, standardized uptake value (SUV) max (1 hour), and the final clinical diagnosis. The site of abnormal accumulation was the esophagus in 1 case, the stomach in 8 and the small intestine to large intestine in 17. In 15 out of 26 (57%) cases with true PET positive results, there was esophageal cancer in 1 case, gastric cancer in 2, gastrointestinal stromal tumor in 1, colon cancer in 8, and 1 each of metastasis to the stomach, small intestine and large intestine from lung cancer. In 11 cases with false PET-positive results, there was a stomach polyp in 1 case, gastritis in 3, colon polyp in 1, diverticulitis in 1 and normal physiologic accumulation in 5. There were no differences in mean SUV max among malignant lesions, benign lesions, and normal physiologic accumulation. We should perform endoscopy of the digestive tract to detect malignant lesions with high incidence rates when PET shows localalized abnormal accumulation in the gastrointestinal, tract in patients with lung cancer.