Association of adipose tissue activity in cervical regions with weight loss and prognostic survival in gastric cancer patients.

[BACKGROUND] With the application of positron emission tomography-computed tomography (PET-CT) in recent years, studies have found that brown adipose tissue is not only present in infants and hibernating mammals but also persists in the neck regions of adults. Cancer-associated cachexia, a complex metabolic syndrome, is characterized by adipose tissue loss and heightened metabolic activity. Despite the profound impact of cachexia on patient outcomes, research into the metabolic dynamics of brown adipose tissue has been sparse. The objective of this study is to quantify the metabolic activity of adipose tissue in the neck regions of gastric cancer patients using PET-CT and to elucidate the relationship between adipose tissue metabolic activity and cachexia, along with its potential predictive value for survival outcomes.

[METHODS] We collected PET-CT imaging data and 18F-fluorodeoxyglucose (FDG) standardized uptake values from the nuchal adipose tissue of 310 patients diagnosed with gastric cancer. Concurrently, we gathered clinical data from these patients to facilitate a thorough analysis. The t-test was employed to evaluate the FDG uptake differences in nuchal adipose tissue between gastric cancer patients exhibiting cancer cachexia or not. The correlation between FDG uptake of nuchal adipose tissue and clinical indicators, along with weight loss and nutritional status, was further analyzed using Spearman's rank correlation test. Kaplan-Meier curves and Cox Proportional Hazards Model were employed to clarify the survival of gastric cancer patients in different FDG uptake groups.

[RESULTS] The 310 gastric cancer patients were divided into 103 patients with cachexia and 207 patients without cachexia. Patients with cachexia exhibited a significantly elevated FDG uptake of nuchal adipose tissue compared to those without cachexia (p < 0.05). Furthermore, correlation analyses demonstrated notable inverse relationships between the FDG uptake of nuchal adipose tissue with body mass index and serum albumin concentrations (p < 0.05). We also observed a positive correlation between the FDG uptake of nuchal adipose tissue with both the weight loss ratio and serum concentrations of tumor necrosis factor-alpha (all p < 0.05). Additionally, patients with elevated FDG uptake of nuchal adipose tissue had a significantly lower survival rate compared to those with lower FDG uptake (p = 0.04). Furthermore, FDG uptake in nuchal adipose tissue was an independent prognostic indicator in gastric cancer patients (HR = 1.81, p = 0.03).

[CONCLUSIONS] In gastric patients with cachexia, the metabolic activity of nuchal adipose tissue was significantly elevated and correlated with weight loss, compromised nutritional status, and an unfavorable survival prognosis. This study could provide valuable insights into the pathophysiology of cachexia and potentially support the development of targeted therapeutic interventions.