Stage IV non-small cell lung cancer (NSCLC) accounts for 35 to 40% of newly diagnosed cases of NSCLC. The oligometastatic state-≤5 extrathoracic metastatic lesions in ≤3 organs-is present in ~25% of patients with stage IV disease and is associated with markedly improved outcomes. We retrospectively identified patients with extrathoracic oligometastatic NSCLC who underwent primary tumor resection at our institution from 2000 to 2018. Event-free survival (EFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Factors associated with EFS and OS were determined using Cox regression. In total, 111 patients with oligometastatic NSCLC underwent primary tumor resection; 87 (78%) had a single metastatic lesion. Local consolidative therapy for metastases was performed in 93 patients (84%). Seventy-seven patients experienced recurrence or progression. The five-year EFS was 19% (95% confidence interval (CI), 12-29%), and the five-year OS was 36% (95% CI, 27-50%). Factors independently associated with EFS were primary tumor size (hazard ratio (HR), 1.15 (95% CI, 1.03-1.29); p = 0.014) and lymphovascular invasion (HR, 1.73 (95% CI, 1.06-2.84); p = 0.029). Factors independently associated with OS were neoadjuvant therapy (HR, 0.43 (95% CI, 0.24-0.77); p = 0.004), primary tumor size (HR, 1.18 (95% CI, 1.02-1.35); p = 0.023), pathologic nodal disease (HR, 1.83 (95% CI, 1.05-3.20); p = 0.033), and visceral-pleural invasion (HR, 1.93 (95% CI, 1.10-3.40); p = 0.022). Primary tumor resection represents an important treatment option in the multimodal management of extrathoracic oligometastatic NSCLC. Encouraging long-term survival can be achieved in carefully selected patients, including those who received neoadjuvant therapy and those with limited intrathoracic disease.
Keywords: non-small cell lung cancer; oligometastasis; primary tumor resection.