Long-Term Outcomes of a Phase 2 Trial of Chemotherapy With Consolidative Radiation Therapy for Oligometastatic Non-Small Cell Lung Cancer

Abstract

Recent data indicate consolidative radiation therapy improves progression-free survival (PFS) for patients with oligometastatic non-small cell lung cancer (NSCLC). Data on long-term outcomes are limited. This prospective, multicenter, single-arm, phase 2 trial was initiated in 2010 and enrolled patients with oligometastatic NSCLC. Oligometastatic disease was defined as a maximum of 5 metastatic lesions for all disease sites, including no more than 3 active extracranial metastatic lesions. Limited mediastinal lymph node involvement was allowed. Patients achieving a partial response or stable disease after 3 to 6 cycles of platinum-based chemotherapy were treated with CRT to the primary and metastatic sites of disease, followed by observation alone. The primary endpoint was PFS, with secondary endpoints of local control, overall survival (OS), and safety. Twenty-nine patients were enrolled between October 2010 and October 2015, and 27 were eligible for consolidative radiation therapy. The study was closed early because of slow accrual but met its primary endpoint for success, which was PFS >6months (P<.0001). The median PFS (95% confidence interval) was 11.2months (7.6-15.9months), and the median OS was 28.4months (14.5-45.8months). Survival outcomes were not significantly different for patients with brain metastases (P=.87 for PFS; P=.12 for OS) or lymph node involvement (P=.74 for PFS; P=.86 for OS). For patients with oligometastatic NSCLC, chemotherapy followed by consolidative radiation therapy without maintenance chemotherapy was associated with encouraging long-term outcomes.