Chest Computed Tomography as a reliable alternative to Lumbar spine Computed Tomography for preoperative sarcopenia assessment in lung cancer patients: A retrospective study

Abstract Background Sarcopenia, characterized by reduced skeletal muscle mass and strength, is a significant risk factor for poor surgical outcomes in lung cancer patients. Accurate preoperative sarcopenia assessment is crucial for optimizing surgical planning and postoperative care. While abdominal computed tomography (CT) at the third lumbar vertebra (L3) is the gold standard, chest CT scans, routinely used for lung cancer screening and staging, do not include this region. Whether thoracic CT measurements can reliably substitute for L3-based assessments remains unclear. This study investigates the feasibility of thoracic CT for preoperative sarcopenia evaluation. Materials and Methods We retrospectively analyzed lung cancer patients who underwent surgery at National Taiwan University Hospital. Inclusion criteria required preoperative CT scans covering both thoracic and lumbar regions. Two widely used sarcopenia indicators, skeletal muscle density and skeletal muscle index, were measured using a U-Net–based deep learning skeletal muscle segmentation model at all thoracic levels and L3. Correlations between thoracic and lumbar measurements were analyzed. Results The cohort included 150 lung cancer patients (44 men, 106 women; median age: 61 years). Strong correlations were identified between T11-T12 and L3 measurements. For skeletal muscle index, correlation coefficients were 0.887 (T11 vs. L3) and 0.897 (T12 vs. L3); for skeletal muscle density, coefficients were 0.988 (T11 vs. L3) and 0.986 (T12 vs. L3), indicating substantial agreement. Conclusions Thoracic CT at T11-T12 provides a reliable alternative for preoperative sarcopenia assessment in lung cancer patients. Utilizing existing imaging can streamline preoperative evaluations, reduce additional imaging needs, lower healthcare costs, and minimize radiation exposure.