Stereotactic Body Radiotherapy for Synchronous Primary Lung Cancer: Clinical Outcome of 18 Cases

BackgroundPrevious reports have shown that curative surgical approaches for synchronous primary lung cancer (SPLC) yielded excellent treatment outcomes. However, patients with SPLC are often unsuitable for such surgery as a result of poor general condition or other medical comorbidities. The effectiveness and feasibility of stereotactic body radiotherapy (SBRT) as a definitive treatment for SPLC are not well understood.Patients and MethodsWe retrospectively reviewed the records of the patients who received lung SBRT between July 2007 and December 2012 at our institution and identified patients with SPLC. The clinical outcome was analyzed for each patient. The first progression site was classified as local, regional, distant, or new primary lung cancer.ResultsA total of 18 patients were eligible. Fifteen patients received SBRT for both lesions, and 3 patients received surgery for one tumor and SBRT for the other. The median follow-up time was 34.3 months (range, 12.2-64.7 months). The median overall and progression-free survival was 45.6 months (95% confidence interval [CI] 21.0-60.6) and 25.3 months (95% CI, 13.1-50.6 months), respectively. The 3-year overall survival and progression-free survival rates were 69.1% (95% CI, 40.7-85.9) and 43.2% (95% CI, 20.2-64.4), respectively. Eleven patients (61%) experienced disease progression. The first progression site was local in 4 (22%), regional in 5 (28%), distant in 3 (17%), and new primary lung cancer in 2 patients (11%). Grade 3 radiation pneumonitis was observed in 2 patients (11%).ConclusionSBRT for SPLC is a highly effective local treatment with limited toxicity, although the progression rate seems relatively high.