Abnormal [(18)F]FDG uptake in liver and adipose tissue: a potential imaging biomarker for cancer-associated cachexia

Elevated 18F-FDG uptake in subcutaneous adipose tissue correlates negatively with nutritional status and prognostic survival in cachexia patients with gastric cancer

BACKGROUND

Browning of white adipose tissue is a crucial factor contributing to adipose loss in cachexia patients, detectable via 18F-Fluorodeoxyglucose (18F-FDG) uptake. The present study elucidates the clinical relevance of 18F-FDG uptake in the subcutaneous adipose tissue of gastric cancer patients, specifically focusing on adipose browning and its implications on patient clinical parameters and prognosis.

METHODS

This investigation encompassed 770 gastric cancer patients, with PET-CT imaging and clinical data meticulously combined. The 18F-FDG uptake in subcutaneous adipose tissue at the third lumbar layer was quantified, and its correlation with clinical parameters, particularly those related to nutritional status and fat metabolism, was examined. Kaplan-Meier curves were subsequently employed to probe the relationship between 18F-FDG uptake and overall survival.

RESULTS

Of the 770 gastric cancer patients, 252 exhibited cancer-associated cachexia, while 518 did not. Cachectic patients demonstrated elevated 18F-FDG uptake in subcutaneous adipose tissue relative to non-cachectic patients (P < 0.001). Increased 18F-FDG uptake was also correlated with reduced plasma concentrations of albumin, prealbumin, hemoglobin, platelets, cholesterol, apolipoprotein A, low-density lipoprotein, and elevated IL-6 concentrations (all P < 0.05). A significant inverse correlation was observed between 18F-FDG uptake and BMI, albumin, low-density lipoprotein, cholesterol, and apolipoprotein A (all P < 0.05). Patients with higher 18F-FDG uptake exhibited diminished overall survival rates compared to those with lower 18F-FDG uptake (P = 0.0065). Furthermore, 18F-FDG uptake in subcutaneous adipose tissue was an independent prognostic indicator in gastric cancer patients (P = 0.028).

CONCLUSIONS

Browning of subcutaneous adipose tissue was markedly elevated in cachectic gastric cancer patients compared to non-cachectic counterparts. Increased 18F-FDG uptake in subcutaneous adipose tissue in cachectic gastric cancer patients was inversely correlated with nutritional status and survival prognosis.

Identification of 18F-FDG PET/CT Parameters Associated with Weight Loss in Patients with Esophageal Cancer

¹⁸F-FDG PET-CT is routinely performed as part of the initial staging of numerous cancers. Other than having descriptive, predictive and prognostic values for tumors, ¹⁸F-FDG PET-CT provides full-body data, which could inform on concurrent pathophysiological processes such as malnutrition. To test this hypothesis, we measured the ¹⁸F-FDG uptake in several organs and evaluated their association with weight loss in patients at diagnosis of esophageal cancer. Forty-eight patients were included in this retrospective monocentric study. ¹⁸F-FDG uptake quantification was performed in the brain, the liver, the spleen, bone marrow, muscle and the esophageal tumor itself and was compared between patients with different amounts of weight loss. We found that Total Lesion Glycolysis (TLG) and peak Standardized Uptake Values (SUV_peak) measured in the brain correlated with the amount of weight loss: TLG was, on average, higher in patients who had lost more than 5% of their usual weight, whereas brain SUV_peak were, on average, lower in patients who had lost more than 10% of their weight. Higher TLG and lower brain SUV_peak were associated with worse OS in the univariate analysis. This study reports a new and significant association between ¹⁸F-FDG uptake in the brain and initial weight loss in patients with esophageal cancer.