Oesophagogastric cancers are associated with high rates of myopenia and myosteatosis

Purpose: Oesophagogastric cancers have a poor prognosis. Body Mass Index (BMI) often does not reflect underlying malnutrition. This study aimed to assess body composition, focusing on myopenia (low muscle mass) and myosteatosis (muscle fat infiltration), and their association with clinical and nutritional parameters. Patients and Methods: Patients diagnosed with oesophagogastric cancer between November 2019 and December 2023 were included in this retrospective study. Skeletal muscle index (SMI) and density (SMD) were assessed via CT scans at the L3 level. Myopenia was defined as SMI < 55.4 cm²/m² (men) and < 38.9 cm²/m² (women); myosteatosis as SMD < 41 HU (BMI < 25 kg/m²) or < 33 HU (BMI ≥ 25 kg/m²). Clinical and nutritional markers were analysed. Results: Among 161 patients (67.1% male, mean age 65.0 ± 12.8 years), 49.1% had oesophageal and 50.9% gastric cancer. Most had adenocarcinoma (64.6%) and 25% had metastases. Mean SMI and SMD were 45.1 ± 10.5 cm²/m² and 24.6 ± 9.6 HU respectively. Despite a normal median BMI (25.2 ± 5.53 kg/m²), myopenia and myosteatosis were prevalent (73.9% and 87.6%, respectively). Myopenic patients were significatively older, with lower BMI and lower albumin serum levels. Myosteatosis was significantly associated to older age, female sex, and lower albumin value. Despite lower muscle density, patients with myosteatosis also had lower SMI (42.3 vs 52.6 cm²/m², p<0.0001). Conclusions: Body composition analysis reveals frequent myopenia and myosteatosis in oesophagogastric cancer mainly associated to poor nutritional status, despite normal BMI. Early identification may guide support and improve outcomes.