Radical local therapy in combination with standard treatment for oligometastatic stage IV non-small-cell lung cancer

Recently, Gomez and colleagues reported the results of a randomized phase II study that aimed to assess progression-free survival (PFS) between aggressive local consolidation therapy versus maintenance therapy or observation in stage IV non-small cell lung cancer (NSCLC) patients with three or fewer metastases remaining after first-line systemic therapy (1). Although systemic therapy, including cytotoxic chemotherapy, and molecular targeted therapy are standard of care for stage IV NSCLC patients and improve overall survival (OS) and quality of life (QOL), stage IV NSCLC patients are generally considered to be incurable and mostly treated with a palliative intent. However, some patients once considered incurable sometimes seem to be potentially curable. One such example is patients with oligometastatic disease. Previous retrospective studies have suggested that a limited number of metastases was a positive prognostic factor in patients with metastatic NSCLC (2) and, in addition, aggressive local therapy has demonstrated survival benefits in patients with oligometastases compared with patients who have not received local therapy (3-5). Furthermore, several prospective studies have also shown clinical benefits of aggressive local therapy in patients with oligometastatic NSCLC. A prospective, single-arm phase II trial of surgery or radiotherapy in combination with systemic chemotherapy in 40 patients with one to five metastases was conducted by De Ruysscher et al. In this trial, median OS was 13.5 months and median PFS was 12.1 months (6). In another phase II study conducted by Iyengar et al. , 24 stage IV NSCLC patients with no more than six sites of extra-cranial disease who failed early systemic chemotherapy were treated with radiotherapy and concurrent erlotinib until disease progression. In this trial, the median PFS was 14.7 months and median OS was
20.4 months (7). These growing evidences have been recognized in the European Society For Medical Oncology (ESMO) and National Comprehensive Cancer Network (NCCN) guidelines, which recommend consideration of radical local treatment as an option for selected patients with oligometastatic disease (8,9).