INTRODUCTION: We hypothesize that reduction in skeletal muscle volume between the time of surgery and the first postoperative surveillance CT scan is associated with recurrence in resected early-stage NSCLC patients. METHODS: Patients who underwent lung resection for pT1-2aN0 NSCLC between 2010-2021 were identified. Exclusion criteria included neoadjuvant/adjuvant therapy, missing CT scan data, and steroid use. Volumetric body composition analysis was performed with Data Analysis Facilitation Suite software using preoperative and initial postoperative surveillance CT scans. A Cox proportional hazards model was used to examine the association between body composition changes and recurrence. RESULTS: Overall, 233 patients were examined, including 63% (147/233) females with a median BMI of 27 (IQR 23-30) kg/m2, and median tumor size of 1.6 (IQR 1.3-2.2) cm. Disease recurrence was observed in 14% (33/233), and the median time to recurrence was 15 (IQR 9-25) months. In patients that recurred, median skeletal muscle percent change was -3.6% (IQR -9.26 to 1.23) and 1.99% (IQR -4.6 to 11.4) in non-recurrent patients. On univariable analysis, loss in skeletal muscle volume >
1% was associated with worse disease-free survival (HR 2.93, CI 1.42- 6.04, p=0.004). On multivariable analysis, after controlling for gender, age, race, BMI, pack-years, FEV1, histology, tumor size, number of nodes, procedure type, and co-morbidities, this association persisted (HR 3.16, CI 1.44-6.94, p=0.004). CONCLUSION: Loss in skeletal muscle volume on first surveillance CT scan is associated with recurrence after resection of early-stage NSCLC.