The influence of tumour fluorodeoxyglucose avidity and cachexia development on patient survival in oesophageal or gastroesophageal junction cancer.

Background And Aims: Cancer cachexia is manifested by loss in muscle, adipose, weight, and appetite. PET F-FDG uptake identifies tumor metabolic and inflammatory changes, potentially associated with cachexia development. We examined if primary gastroesophageal tumor F-FDG uptake correlates with cachexia development and survival in cancer patients.

Methods: One hundred twenty-six esophageal (n=87) and gastroesophageal junction (n=39) cancer patients, with a median age at diagnosis of 63 years (IQR 54-71), evaluated between 2006-2014 with pre-treatment PET imaging and cachexia determination at diagnosis were included in the study cohort (22.1% female; 6.7%, 24.4%, 50.4%, and 18.5% with tumor stage I, II, III, and IV respectively). Maximum primary tumor standardized uptake values (SUV) were obtained and dichotomized based off the calculated cut-point SUV of 8.5 (P=.0018). Associations between survival, cachexia development and primary tumor F-FDG uptake were evaluated using univariate and multivariate analyses.

Results: Cancer-associated weight loss (cachexia) and primary tumor SUV at or above the statistically determined cut-point of 8.5 were present in 54% and 57% of patients, respectively. Primary tumor SUV above the cut-point was significantly associated with pre-treatment cancer-associated weight loss (P=.0033) and, in multivariate analysis, correlated with a 2.3-fold increased risk of death (95% CI 1.4, 3.7; P=.0010). When divided into cohorts defined by their combined cachexia and high versus low SUV tumor status, positive cachexia status or/and high SUV tumors were associated with similar significant decrements in survival.

Conclusion: A positive association was present between cancer-associated weight loss and SUV of the primary tumor, suggesting greater glycolytic metabolism in gastroesophageal tumors that induce cachexia. This interpretation of routinely administered PET scans could lead to earlier categorization of patients with cachexia-inducing tumors. Both cachexia and high SUV status were independently associated with worsened survival outcomes, further supporting their prognostic relevance in patients with gastroesophageal cancer.