MOY 2 - ‘Cachexia Index’ for Prognostication in Surgical Patients with Locally Advanced Oesophageal or Gastric Cancer: A Multicentre Cohort Study

Abstract Background Features of cancer cachexia are known to adversely influence patient outcomes, yet few currently inform clinical decision-making. This study assessed the value of ‘cachexia index’ (CXI), a novel prognostic marker, in patients planned for curative multimodal therapy (neoadjuvant chemotherapy (NAC) and surgery) for oesophagogastric cancer. Methods Consecutive patients newly diagnosed with locally advanced (T3/4 or ≥N1) oesophagogastric cancer were identified through the West of Scotland and South-East Scotland Cancer Networks. CXI was calculated as (L3 skeletal muscle index) x (serum albumin) / (neutrophil-lymphocyte-ratio). Sex-stratified cut-off values were determined based on area under the curve (AUC), and patients were divided into low and normal CXI groups. Primary outcomes of interest were disease progression during NAC and overall survival (≥5-years follow-up). Results Overall, 385 patients (72% male, median 66 years) were treated with NAC for oesophageal (n=274) or gastric (n=111) cancer across the study period. While patients with a low CXI (males: <52 [AUC: 0.691] and females: <41 [AUC: 0.759]) were older and more comorbid, disease characteristics were comparable to those with a normal CXI. Rates of disease progression during neoadjuvant chemotherapy, leading to inoperability, were higher in patients with low CXI (28% vs. 12%, aOR: 3.07 (95% CI: 1.67-5.64), p<0.001). Moreover, low CXI was associated with worsened post-operative mortality (p=0.019) and decreased overall survival (median: 14.9 vs. 56.9 months, aHR: 1.85 (95% CI: 1.42-2.42), p<0.001). Conclusion CXI represents a valuable marker of ‘host stage’, and a potential adjunct to routine tumour staging. This could improve prognostication and decision-making in patients with locally advanced oesophagogastric cancer.