Local Control for Clinical Stage I Non-Small Cell Lung Cancer Treated with 5-Fraction Stereotactic Body Radiation Therapy is Not Associated with Treatment Schedule.

PURPOSE:Clinical concern remains regarding the relationship between consecutive (QD) versus nonconsecutive (QoD) lung stereotactic body radiation therapy (SBRT) treatment schedules and outcomes for clinical stage I non-small cell lung cancer (NSCLC). We examined a multi-institutional series of patients receiving 5-fraction lung SBRT to compare the local failure rates and overall survival between patients receiving QD versus QoD treatment.METHODS AND MATERIALS:Lung SBRT databases from 2 high-volume institutions were combined, and patients receiving 5-fraction SBRT for a solitary stage I NSCLC were identified. QD treatment was defined as completing SBRT in ≤7 days, whereas QoD treatment was defined as completing treatment in >7 days. To control for patient characteristics between the 2 institutions, a 1:1 propensity-matched analysis was performed. Multivariable logistic regression was performed to identify variables independently associated with local failure, and Cox proportional hazards modeling to identify variables independently associated with increased mortality.RESULTS:From 2005 through 2016, 245 clinical stage I NSCLC patients receiving 5-fraction SBRT were identified. A total of 117 (47.8%) patients received QD treatment and 128 (52.2%) patients received QoD treatment. On propensity-matched analysis, no association was seen between QD treatment and local failure (odds ratio [OR] for QD treatment, 0.48; 95% confidence interval [CI], 0.12-1.99; P = .5). On multivariable logistic regression, central tumors were independently associated with increased likelihood of local recurrence (OR, 5.2; 95% CI, 1.11-24.2; P = .04). Kaplan-Meier analysis identified no difference in median overall survival between QD versus QoD treatments (38.0 vs 38.0 months, log-rank P = .7), respectively. QD treatment was not associated with an increased mortality hazard (hazard ratio, 1.08; 95% CI, 0.67-1.75; P = .75).CONCLUSIONS:This analysis demonstrated no association between QD versus QoD treatment scheduling and local control or overall survival for early-stage NSCLC.