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.