ABSTRACT: BACKGROUND:Video-assisted thoracic surgery (VATS) has been shown to effectively reduce postoperative pain, enhance mobilization of the patients, shorten in-hospital length of stay, and minimize postoperative morbidity rates. The aim of this prospective study is to evaluate neuroendocrine and respiratory parameters as stress markers in cancer patients who underwent lung wedge resections, using both mini muscle-sparing thoracotomy and VATS approach. METHODS:The patients were randomly allocated into two groups: Group A (n=30) involved patients who were operated on using the VATS approach, while in group B (n=30), the mini muscle-sparing thoracotomy approach was used. Neuroendocrine and biological variables assessed included blood glucose levels, C-reactive protein (CRP) levels, cortisol, epinephrine, and adrenocorticotropic hormone (ACTH) levels. Arterial oxygen (PaO2) and carbon dioxide (PaCO2) partial pressure were also evaluated. All parameters were measured at the following time points: 24 hours preoperatively (T1), 4 hours (T2), 24 hours (T3), 48 hours (T4), and 72 hours (T5), after the procedure. RESULTS:PaO2 levels were significantly higher 4 and 24 hours postoperatively in group A vs group B, respectively (T2: 94.3 vs 77.9 mmHg, P=0.015, T3: 96.4 vs 88.7 mmHg, P=0.034). Blood glucose (T2: 148 vs 163 mg/dL, P=0.045, T3: 133 vs 159 mg/dL, P=0.009) and CRP values (T2: 1.6 vs 2.5 mg/dL, P=0.024, T3: 1.5 vs 2.1 mg/dL, P=0.044) were found increased in both groups 4 and 24 hours after the procedure. However, their levels were significantly lower in the VATS group of patients. ACTH and cortisol values were elevated immediately after the operation and became normal after 48 hours in both groups, without significant difference. Postoperative epinephrine levels measured in group A vs group B, respectively, (T2: 78.9 vs 115.6 ng/L, P=0.007, T3: 83.4 vs 122.5 ng/L, P=0.012, T4: 67.4 vs 102.6 ng/L, P=0.021). The levels were significantly higher in group B. CONCLUSION:This study confirmed that minimally invasive thoracic surgery, by means of VATS, significantly reduces the acute-phase response and surgical stress, while enables better postoperative oxygenation.