Tumor Regression Following Neoadjuvant Therapy as a Determinant of Surgical Resectability in Stage IIIA Non-small Cell Lung Cancer: A Comparative Clinical Study.

Background This study explored whether tumor regression following neoadjuvant therapy can be used as a reliable indicator of surgical operability in patients with stage IIIA non-small cell lung cancer (NSCLC). Methods A retrospective cohort analysis was performed, including patients with stage IIIA NSCLC treated at a tertiary thoracic surgery center. Patients were categorized according to treatment approach: induction therapy followed by surgery or primary surgical management. Treatment response was assessed using imaging findings, pathological staging changes, residual tumor burden, and lymph node status. Surgical feasibility and perioperative outcomes were evaluated. Statistical significance was defined at p<0.05. Results Patients receiving induction therapy demonstrated greater tumor reduction, higher rates of mediastinal nodal regression, and more frequent complete pathological response. Complete (R0) resection was achieved more often in this group. Tumor regression and nodal response were identified as independent predictors of surgical feasibility. Postoperative complication rates and mortality did not differ significantly between groups. Conclusion Tumor response after neoadjuvant therapy is closely associated with surgical operability in stage IIIA NSCLC. Response-based selection may improve resectability without increasing perioperative risk.