Role of fluoro-2-deoxyglucose positron emission tomography for the detection of gastrointestinal tract lesions in patients with lung cancer

Background: The purpose of this study was to clarify the clinical characteristics of lung cancer patients with abnormal accumulation of fluoro-2-deoxyglucose (FDG) in the gastrointestinal tract imaged by positron emission tomography (PET). Methods: Of 1071 consecutive patients with primary lung cancer who underwent PET from October 2005 through to March 2010, 25 patients (2.3%) showed localized abnormal FDG accumulation in the gastrointestinal tract. We retrospectively compared the location of abnormal accumulation in the gastrointestinal tract, the maximum standardized uptake value in 1 hour, and final clinical diagnosis. Results: Of the 25 cases, 12 (48%) were true PET-positive cases (esophageal cancer in one case, gastric cancer in one, colorectal cancer in seven, gastrointestinal stromal tumor in one, and lung cancer metastasis to the stomach and small intestine in one patient each). The 13 cases with false PET-positives were gastric polyp in one, gastritis in four, colon polyp in two, diverticulitis in one, and normal physiological accumulation in five. There was also a significant difference between malignancy and benign intestinal accumulation excluding the stomach (P = 0.002). Conclusion: PET was useful for screening the gastrointestinal tract (except the stomach) for malignancy in lung cancer patients.