LAUSR

Background Stereotactic body radiation therapy (SBRT) is an emerging therapy for oligometastatic cancer. The aim of this study was to investigate the efficacy and safety of high-dose radiotherapy for primary and oligometastatic lesions in epidermal growth factor receptor (EGFR) wild-type non-small cell lung cancer (NSCLC). Methods A total of 40 EGFR wild-type oligometastatic NSCLC patients (defined as ≤5 metastases) treated with SBRT in our department between 2009 and 2016 were analyzed retrospectively. SBRT was delivered to the lesions with a median biologically effective dose at alpha/beta 10 (BED10) value of 102.7 Gy (range, 94.5–113.5 Gy). Primary endpoints including progression-free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method. Factors potentially affecting OS and PFS were evaluated by univariate and multivariate Cox-regression analyses. Results After a median follow-up of 39 months, the median OS observed in this study was 40 months (95% CI: 32.562–47.438 months). One-, 2-, and 3-year OS rates were 100.0%, 72.5%, and 62.5% respectively. Twenty-nine patients (72.5%) succumbed to tumor burden and median PFS was 13 months (range, 10.687–15.313 months). One-, 2-, and 3-year PFS rates were 65.0%, 10.0%, and 0% respectively. Multivariate analysis suggested Eastern Cooperative Oncology Group performance status (ECOG PS) <2 and high-dose radiation regimens were independent prognostic factors of longer OS (P<0.001 and 0.049, respectively), and patients receiving radiotherapy with BED10 ≥100 Gy showed a better PFS than those undergoing low dose (P=0.047). There were no patients of CTCAE v 5.0 grade 4–5 toxicity or treatment-related deaths. Grade 3 toxicity occurred in 2 (5.0%) patients and 36 (90.0%) patients experienced grade 1–2 adverse reactions. Conclusions The current study suggested systemic chemotherapy combined with SBRT for pulmonary and metastatic lesions was feasible and tolerable to improve outcomes of EGFR wild-type oligometastatic NSCLC patients.