Comparison of Long-Term Survival Outcomes Between Stereotactic Body Radiation Therapy and Sublobar Resection for Stage I Non-Small Cell Lung Cancer in High-Risk Operable Patients: Propensity Score Match Analysis

Abstract

Stereotactic body radiation therapy (SBRT) is being a standard treatment option for medically inoperable patients with stage I non-small cell lung cancer (NSCLC). However, its role is still unclear in high-risk operable patients who cannot tolerate lobectomy. The purpose of this study is to perform a survival comparison between SBRT and sublobar resection (SLR). All patients who underwent SBRT or sublobar resection (SLR) because of medical comorbidity for clinical stage I NSCLC between January 2003 and December 2009 were retrospectively reviewed. Patients with tumor diameter >50 mm or those without histological confirmation were excluded. Propensity score matching (PSM) was performed based on age, sex, performance status (PS), tumor diameter, forced expiratory volume in 1 second (FEV1) and Charlson comorbidity index (CCI). 115 patients of SBRT and 65 of SLR were eligible for this study. Median potential follow-up periods for SBRT and SLR were 6.7 and 5.3 years, respectively. Patients with SBRT were elderly, poorer in PS, lower in FEV1, higher in CCI, and larger in tumor diameter than those with SLR. Two patients were upstaged to pathological IIIA after SLR because of mediastinal node metastasis. No patients received adjuvant chemotherapy until disease progression. No treatment-related death was observed either in SBRT or in SLR. Before the PSM, 5-year overall survival (OS) was 40.3% and 60.5% for SBRT and SLR, respectively (P<0.01). The PSM picked up 53 patients for each treatment group. After the PSM, difference in OS became insignificant (40.4% and 55.6% at 5 years for SBRT and SLR, respectively; P = 0.12). Furthermore, cumulative incidence of cause-specific death was similar in the two groups (35.5% and 30.3% at 5 years, P = 0.43). Although local recurrence tended to be higher in SBRT (28.4% and 14.1%, P = 0.06), regional or distant metastasis was not significantly different between the two treatment (14.3% and 9.2% for regional, P = 0.24; 35.9% and 36.1% for distant, P = 0.67). SBRT can be an alternative treatment to SLR for those who cannot tolerate lobectomy because of medical comorbidity.