Prognostic impact of muscle mass loss in elderly patients with oesophageal cancer receiving neoadjuvant chemoradiation therapy

Background We aimed to identify the impact of muscle mass on locally advanced oesophageal cancer (LAEC) in elderly patients receiving neoadjuvant chemoradiation therapy (NACRT). Methods We reviewed the medical records of 345 patients diagnosed with LAEC who underwent NACRT and surgery. Physical variables, including height, weight, skeletal muscle mass, and laboratory values, were obtained before and after NACRT. Body mass index (BMI, kg/m2), neutrophil‐to‐lymphocyte ratio (NLR), platelet‐to‐lymphocyte ratio (PLR), and prognostic nutritional index (PNI) were calculated as height/(weight)2, ANC/ALC, platelet count/ALC, and (10 × albumin + 0.05 × ALC), respectively. The cutoff for low muscle mass was 43.0 cm2/m2 for BMI below 25 kg/m2 and 53.0 cm2/m2 for BMI 25 kg/m2 or higher. The skeletal muscle index (SMI) was defined as skeletal muscle area/(height)2 (cm2/m2). The ΔSMI (%/50 days) was defined as (SMI after NACRT − SMI before NACRT)/interval (days) × 50 (days) to compare changes over the same period. The excessive muscle loss (EML) group was defined as patients with ΔSMI ≤−10% following NACRT. An elderly patient was defined as aged ≥65 years. The primary outcome measure was overall survival (OS). Results During a median follow‐up of 32.8 months (range, 2.0–176.2), 192 patients died, with a median OS of 50.2 months. Elderly patients did not show inferior OS (young vs. elderly, 57.7% vs. 54.0% at 3 years, P = 0.247). 71.0% and 87.2% of all patients had low muscle mass before and after NACRT, respectively, which was not associated with OS (P = 0.270 and P = 0.509, respectively). Inflammatory (NLR and PLR) and nutritional index (PNI) values or their changes did not correlate with OS. However, the EML group had worse OS (41.6% vs. 63.2% at 3 years, P