Is Adjuvant Radiochemotherapy Always Mandatory in Patients with Resected N2 Non-Small Cell Lung Cancer?

BACKGROUND: In patients with non-small cell lung cancer (NSCLC), the pathologic union for international cancer control (UICC) stage IIIA is a heterogeneous entity, with different forms of N2-lymph node involvement representing different prognoses. Although a multimodality treatment approach, including surgery, systemic therapy, and/or radiotherapy, is almost always recommended, in this retrospective observational study, we sought to determine whether long-term survival might be possible in selected patients who are treated with complete surgical resection alone. METHODS: Between 2013 and 2018, we retrospectively identified 24 patients with NSCLC (16 men and 8 women), who were found to have pathologic N2-lymph node involvement, and were treated with complete surgical lung resection and systematic mediastinal and hilar lymph node dissection but no neoadjuvant or adjuvant treatment. RESULTS: The most frequent reason (n = 14) for forgoing adjuvant treatment was patient refusal. The mean overall survival (OS) was 34.5 months (interquartile range [IQR]: 15.5-53.5 months). The mean disease-free survival (DFS) was 18 months (IQR: 4.75-46.75 months). We identified five patients who survived at least 5 years without recurrence (21%). In each of these cases, the nodal metastases were restricted to a single level and no extracapsular lymph node involvement were detected. Additionally, worse DFS was associated with pT3/4 (vs. a lower T-stage), as well as microscopic lymphovascular invasion. CONCLUSION: Although the small sample size precludes any definitive conclusions, it was possible to demonstrate that long-term survival without neoadjuvant and adjuvant treatment is possible in some patients if complete tumor and nodal resection is performed.