The assessment of surgical and postoperative risks in thoracic surgery is a field of significant interest because the surgical procedure causes substantial changes in the body's homeostasis. The postoperative course is characterized by considerable clinical variability compared to the preoperative classification, which highlights more homogeneous data among various patient groups. This variability appears to result from individual differences in response to extensive pulmonary resections. Notably, the homogeneity of preoperative data does not correlate with the greater variability observed in the postoperative course. The application of algorithms derived from BIVA in bioimpedance studies has proven particularly useful for prognostic assessments in oncology, as it can evaluate a patient's hydration status and muscle reserves at the time of diagnosis or the start of clinical/surgical treatment. Understanding body composition, particularly the quantity and/or quality of muscle mass, is essential for diagnosing sarcopenia. By passing a low-intensity alternating current (imperceptible to the patient) through the body, BIVA measures provide insights into body water distribution (both intracellular and extracellular), lean mass and skeletal muscle mass. Overall, the test offers a detailed picture of hydration status and skeletal muscle composition. Another validated tool for assessing sarcopenia, which provides information on both muscle quantity (via cross-sectional area measurements) and muscle quality (via muscle density measurements), is computed tomography (CT). CT imaging is typically performed for diagnostic and staging purposes before surgery in thoracic surgery patients, either alone or in combination with positron emission tomography (PET). Our study will focus on assessing correlations between clinical, imaging, and bioimpedance data and postoperative outcomes, with particular attention to the incidence of atrial fibrillation (AF), pulmonary atelectasis requiring treatment, and increased pleural drainage production. Additionally, we will evaluate the relationship between the surgical approach (open surgery vs. video-assisted thoracoscopic surgery, or VATS) and short-term bioimpedance values.