Local ablative therapy with or without chemotherapy for non-small-cell lung cancer patients with postoperative oligometastases

BACKGROUND: The optimal treatment strategy for patients with non-small-cell lung cancer (NSCLC) with postoperative oligometastases is poorly defined. This two-institution analysis sought to retrospectively compare the efficacy and toxicity of local ablative treatment plus chemotherapy vs local treatment alone in patients with NSCLC who developed oligometastases after surgery. PATIENTS AND METHODS: Among patients who underwent surgery for stage I–III NSCLC, 163 patients with oligometastases were enrolled between 2005 and 2016 in this study. All patients had ≤5 metachronous metastases with a disease-free interval (DFI) of ≥6 months after surgery. Patients with a second primary cancer, local recurrence, or driver mutations were excluded. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), failure patterns, and treatment-related toxicities were compared between groups receiving local ablative treatment plus chemotherapy and local treatment alone. RESULTS: A total of 105 patients who underwent local ablative therapy combined with chemotherapy and 58 patients who received local ablative therapy alone were included in this study. The median follow-up was 19 (range, 1.5–107) months. The combination therapy group had a higher ORR than the local therapy alone group (66.7% vs 46.5%, P=0.012), while the median PFS was 10 vs 7 months (P=0.006) and the median OS was 19 vs 18.5 months (P=0.498), respectively. By multivariate analysis, combination therapy and DFI ≥24 months were associated with superior PFS. Age was the only independent prognostic factor for OS (P<0.001). The incidences of grade ≥3 adverse events were higher in the combination treatment group. CONCLUSION: Local ablative therapy plus chemotherapy conferred higher ORR and prolonged PFS but did not improve OS in NSCLC patients with postoperative oligometastases. Further prospective and randomized trials are urgently needed to validate these findings.