BACKGROUND: Cachexia is common in patients with oesophagogastric cancer. The syndrome is characterised by tissue wasting (muscle and fat), anorexia, and reduced physical function, which result from complex interactions between the tumour and its host. Heterogeneity in the diagnostic criteria used for cachexia has hindered their clinical utilisation. This study aimed to compare the two established cachexia definitions (Fearon's consensus definition and the Global Leadership Initiative on Malnutrition [GLIM] criteria) and their relationships with survival in patients with oesophagogastric cancer. METHODS: Consecutive patients newly diagnosed with oesophagogastric cancer (January 2019 to December 2020) were identified from a prospective regional database. Involuntary weight loss, BMI, CT body composition analyses, and neutrophil-lymphocyte ratios were recorded at clinical staging. These data were used to assess patients for cachexia according to Fearon and GLIM diagnostic criteria. The primary outcome of interest was overall survival. RESULTS: Overall, 465 patients (66.9% male, median 71 years) were diagnosed with oesophagogastric cancer during the 2-year study period. Cachectic proportions differed between definitions (Fearon: 59.1% vs. GLIM: 44.1%), and only 49.1% of the 322 patients who met one set of diagnostic criteria were cachectic according to both. Patients who met the GLIM criteria were significantly more comorbid and had a poorer performance status
however, no such difference was evident when using the Fearon definition. Those patients who met either set of diagnostic criteria had shorter survival than those who met neither ( CONCLUSIONS: Cancer cachexia is strongly associated with shortened survival in patients with oesophagogastric cancer. Classification using the GLIM criteria provides more effective prognostication and this definition should be utilised in multidisciplinary patient care.