Four-year follow-up outcomes after stereotactic body radiation therapy for central early-stage non-small cell lung cancer

BACKGROUND: Previous research has shown that stereotactic body radiation therapy (SBRT) can achieve a high level of tumor control in patients with early-stage non-small cell lung cancer (NSCLC). However, to date, such studies have mainly focused on peripheral early-stage patients. This study aimed to assess the clinical outcomes and toxicity of patients with central lung cancer treated with SBRT in our institution. METHODS: A total of 31 consecutive central early-stage NSCLC patients who were treated with SBRT using the biologically effective dose (BED; α/β =10) 100–119 Gy in 4–10 fractions between April, 2013, and August, 2016, were reviewed. The RTOG 0813 trial standard was used to define whether the NSCLC was centrally located. All patients received four-dimensional computed tomography (4D CT) simulation. Intensity modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D CRT) techniques were used in treatment planning. The dose to the planning target volume (PTV) was prescribed to the 95% isodose line. Mainly dosimetric parameters, clinical outcomes, and toxicity were analyzed. RESULTS: The 31 patients enrolled in the study had a median follow-up time of 47.7 months, and the median tumor diameter was 2.2 cm (range, 1.3–5.0 cm). A total of 15 patients (48.4%) developed disease recurrence. The incidences of local, regional, and distant disease recurrence at 3 years were 11.7%, 9.7%, and 30.7%, respectively; at 5 years, they were 21.5%, 15.0%, and 35.0%, respectively. The 3- and 5-year progression-free survival (PFS) rates were 55.1% and 40.5%, respectively; the corresponding overall survival (OS) rates were 85.3% and 68.4%, respectively. Toxicities of grade 3 or higher were observed in 6.5% of the patients. None of the patients experienced grade 4 or 5 acute adverse events; however, 2 patients possibly died of treatment-related late toxicity. CONCLUSIONS: SBRT with a BED 100 Gy in 4–10 fractions is effective and acceptable for treating patients with central early-stage NSCLC. Further studies are warranted.