Clinical significance of visual cardiac 18F-FDG uptake in advanced non-small cell lung cancer

Background: Two-deoxy-2-[fluorine-18]-fluoro-d-glucose (18F-FDG) positron emission tomography (PET) is useful for detecting malignant lesions; however, the clinical significance of cardiac 18F-FDG uptake in patients with cancer remains unclear. This preliminary study explored the relationship between cardiac 18F-FDG uptake and advanced diseases such as cancer cachexia in non-small cell lung cancer (NSCLC). Methods: Forty-three patients with advanced NSCLC who underwent 18F-FDG PET and complained of weight loss before the first-line systemic therapy were retrospectively included in this study. Visual assessment using a 5-point scale based on 18F-FDG uptake was performed; a cut-off score of 3 was determined, a low score was 1, 2, or 3, and a high score was 4 or 5). Results: High and low visual cardiac 18F-FDG uptakes were observed in 27 (62.8%) and 16 (37.2%) patients, respectively. Of the 43 patients, 17 (39.5%) definitely had cachexia, and 26 (60.5%) did not. A low visual score and standardized uptake valuemax for cardiac 18F-FDG uptake were significantly associated with high metabolic tumor activity and a high neutrophil-to-lymphocyte ratio, whereas a low visual score for cardiac 18F-FDG uptake and high metabolic tumor activity were significantly associated with cachexia. The amount of cardiac 18F-FDG accumulation depicted a close relationship with body mass index, low weight loss, and inflammation. The combination of cachexia and low visual cardiac 18F-FDG uptake was identified as a significant predictor for poor overall survival (OS). Conclusion: Decreased visual cardiac 18F-FDG uptake was associated with poor nutritional status and OS, and cachexia in patients with advanced NSCLC.