Stereotactic body radiotherapy (SBRT) is a well-established treatment option for early stage non-small-cell lung cancer (NSCLC) tumors < 5 cm. There is limited information on tumors > 5 cm.

We performed retrospective data collection of patients enrolled onto a prospective SBRT registry study. Eligible patients for this study had node-negative NSCLC measuring > 5 cm in any dimension. Data from 41 patients were analyzed. Median patient age was 75 years, and median tumor size was 5.6 cm (range, 5.0-12.2 cm). Sixteen patients had squamous disease, 20 patients adenocarcinoma, and 1 mixed tumor; 4 patients had no biopsy. Median radiation dose per fraction was 50 Gy in 5 fractions. Radiation was prescribed to isodose line, median 66% (range, 50%-84%).

Before SBRT, 6 patients had previous chemotherapy and 7 patients had previous radiation. Median follow-up for all patients was 15.2 months (range, 0.56-48.1 months). At last follow-up, 16 patients were still alive, with a median follow-up of 16.1 months for surviving patients. The median survival was 17.5 months with 1- and 2-year survivals of 65% and 34%. Two patients (4.8%) had local failure, and 13 patients (31%) had distant failure. Four patients (9.8%) had acute toxicity, and 7 patients (17.1%) had late toxicity, including 2 (4.8%) grade 3 late toxicities.

SBRT for tumors > 5 cm is effective, with good local control rates and acceptable toxicity. The main pattern of failure is distant, suggesting a possible role for systemic chemotherapy in these patients.