Phase II study of stereotactic body radiotherapy to primary tumor and metastatic locations in oligometastatic nonsmall-cell lung cancer patients

Background: Stereotactic body radiotherapy (SBRT) has emerged as a treatment modality in patients presenting with oligometastatic nonsmall-cell lung cancer (NSCLC). SBRT is used as a local consolidative treatment to metastatic disease sites. The majority of patients included in SBRT trials for oligometastatic NSCLC have controlled primary tumors and brain metastases. Patients and methods: Oligometastatic NSCLC patients with <= 5 metastatic lesions were included in a prospective phase II trial to evaluate efficacy and toxicity of SBRT to all disease sites, primary tumor and metastatic locations. SBRT to a dose of 50 Gy in 10 fractions was delivered. Positron emission tomography-computed tomography (PET-CT) was carried out at baseline and 3 months after SBRT to evaluate the metabolic response rate according to PET Response Criteria in Solid Tumors (PERCIST). The progression-free survival (PFS) and overall survival (OS) were calculated using Kaplan-Meier method from start of chemotherapy or radiotherapy. Side-effects were scored using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 3.0. Results: Twenty-six patients received SBRT after induction chemotherapy (n = 17) or as a primary treatment (n = 9). Median follow-up was 16.4 months. Overall metabolic response rate was 60% with seven patients (30%) achieving a complete metabolic remission and 7 (30%) a partial metabolic response. Any acute grade 2 toxicity was observed in four patients (15%) and grade 3 pulmonary toxicity in two patients (8%). Median PFS and OS were 11.2 and 23 months. The 1-year PFS and 1-year OS rate were 45% and 67%, respectively. Conclusion: SBRT to all disease sites, primary tumor and metastatic locations, in oligometastatic NSCLC patients produced an acceptable median PFS of 11.2 months.