P2.05-007 Outcomes after Stereotactic Body Radiothrapy/Proton Beam Therapy or Wedge Resection for Stage I Non-Small-Cell Lung Cancer: Topic: Clinical Outcome

Abstract

Recently, excellent results of stereotactic body radiotherapy (SBRT), proton beam therapy (PBT) for stage I non-small-cell lung cancer (NSCLC) have been reported, however any phase III trial comparing SBRT and surgery have not been completed yet. The aim of this study is to compare outcomes between SBRT, PBT and wedge resection (WR) for patients with peripheral stage I NSCLC who intolerable for anatomical resection, and analyze prognostic factors in this population. We retrospectively compared overall survival (OS), local recurrence rate (LRR), relapse-free survival (RFS) and cause-specific survival (CSS) between WR (n=172) and SBRT / PBT (n=188) for pathologically proven clinical stage I NSCLC in our institute from 2002 to 2015. Patients underwent WR were all high risk patients who intolerable for anatomical resection and achieved complete resection without any adjuvant therapy. Of radiation group (RT: SBRT+PBT), 56% was medically inoperable, with 44% refusing surgery. SBRT; 60 Gy in 8 fractions, PBT; 60-80 GyE in 10-20 fractions was prescribed. Propensity score matching was used to adjust the confounding effects in estimating treatment hazard ratios. 59 WR patients and 59 radiotherapy (RT) patients (SBRT 27, PBT 32) were matched blinded to outcome (1:1 ratio). There are 70 men and 48 women, median age was 81, and median follow-up period was 39 months. 3, 5 - year overall survival (OS) of WR and RT was 84.5%, 70.8% vs 89.7%, 59.6% (p=0.802), respectively. 3-year LRR, RFS, CSS were 94.7% vs 95.9% (p=0.751), 87.5% vs 75.6% (p=0.151) and 91.2% vs 93.9% (p=0.875), respectively. Multivariate analysis of prognostic factors for OS demonstrated any factors including treatment modality were not significant. Our results suggest that the treatment outcome of SBRT / PBT was equivalent to that of WR, SBRT / PBT may be alternative treatment in stage I NSCLC high risk patients.