Long-Term Survival and Failure Outcomes of Single-Fraction Stereotactic Body Radiation Therapy in Early Stage NSCLC.

Introduction: This study aims to report our 13-year institutional experience with single-fraction stereotactic body radiation therapy (SF-SBRT) for early stage NSCLC. Methods: A single-institutional retrospective review of patients with biopsy-proven peripheral cT1-2N0M0 NSCLC undergoing definitive SF-SBRT between September 2008 and May 2022 was performed. All patients were treated to 27 Gy with heterogeneity corrections or 30 Gy without. Primary outcomes were overall survival and progression-free survival. Secondary outcomes included local failure, nodal failure, distant failure, and second primary lung cancer. Results: Among 263 eligible patients, the median age was 76 years (interquartile range [IQR]: 70-81 y) and median follow-up time was 27.2 months (IQR: 14.25-44.9 mo). Median tumor size was 1.9 cm (IQR: 1.4-2.6 cm), and 224 (85%) tumors were T1. There were 92 patients (35%) alive at the time of analysis with a median follow-up of 34.0 months (IQR: 16.6-50.0 mo). Two- and five-year overall survival was 65% and 26%, respectively. A total of 74 patients (28%) developed disease progression. Rates of five-year local failure, nodal failure, distant failure, and second primary lung cancer were 12.7%, 14.7%, 23.5%, and 12.0%, respectively. Conclusions: Consistent with multiple prospective randomized trials, in a large real-world retrospective cohort, SF-SBRT for peripheral early stage NSCLC was an effective treatment approach.

Comparison of Survival Outcomes of Single- and Five-Fraction Schedules of Stereotactic Body Radiation Therapy for Early-Stage Central or Peripheral NSCLC.

BACKGROUND: The treatment of early-stage non-small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT) frequently involves different fractionation schemes for peripheral and central tumors due to concerns with toxicity. We performed an observational cohort study to determine survival outcomes for patients with peripheral and central NSCLC treated with SBRT. METHODS: A single-institutional database of patients with early-stage NSCLC treated with SBRT from September 2008 to December 2018 was evaluated. Outcomes were progression-free survival (PFS), overall survival (OS), local failure (LF), nodal failure (NF), and distant failure (DF). Cox multivariable analysis (MVA), Kaplan-Meier plotting, Fine-Gray competing risk MVA, and propensity score matching were performed. RESULTS: A total of 265 patients were included with a median follow-up of 44.2 months. There were 191 (72%) and 74 (28%) patients with peripheral and central tumors treated with single-fraction SBRT to a dose of 27 Gy and five-fraction SBRT to a dose of 50 Gy, respectively. On Cox MVA, there was no difference in OS (adjusted hazards ratio (aHR) of 1.04, 95% CI of 0.74-1.46) or PFS (aHR of 1.05, 95% CI of 0.76-1.45). On Fine-Gray competing risk MVA, there were no differences in LF, NF, or DF. Propensity matching confirmed these findings. CONCLUSION: The survival outcomes of patients treated with SBRT for early-stage NSCLC were equivalent for central and peripheral tumors.

Association of neutrophil-lymphocyte ratio with survival in peripheral early-stage non-small cell lung cancer after stereotactic body radiation therapy.

BACKGROUND: The role of neutrophil-lymphocyte ratio (NLR) as a predictor for survival in single fraction SBRT-treated non-small cell lung cancer (NSCLC) patients remains unclear. We performed an observational cohort study to determine the role of pretreatment NLR in predicting survival of early-stage NSCLC patients after single fraction SBRT. METHODS: A single-institution database of peripheral early-stage NSCLC patients treated with SBRT from February 2007 to May 2022 was queried. Optimal threshold of neutrophil-lymphocyte ratio (NLR) was defined based on maximally selected rank statistics. Cox multivariable analysis (MVA), Kaplan-Meier, and propensity score matching were performed to evaluate outcomes. RESULTS: A total of 286 patients were included for analysis with median follow up of 19.7 months. On Cox multivariate analysis, as a continuous variable, NLR was shown to be an independent predictor of OS (adjusted hazards ratio [aHR] 1.06, 95% CI 1.02-1.10, p = 0.005) and PFS (aHR 1.05, 95% CI 1.01-1.09, p = 0.013). In addition, NLR was associated with DF (aHR 1.11, 95% CI 1.05-1.18, p < 0.001). Maximally selected rank statistics determined 3.28 as the cutoff point of high NLR versus low NLR. These findings were confirmed upon propensity matching. CONCLUSIONS: Pretreatment NLR is an independent predictor for survival outcomes of peripheral early-stage NSCLC patients after single fraction SBRT.

Brachial Plexopathy After Single-Fraction Stereotactic Body Radiation Therapy in Apical Lung Tumors.

PURPOSE: The objective of this study was to evaluate the incidence of brachial plexus injury (BPI) after single-fraction stereotactic body radiation therapy (SBRT) to apical lung tumors. METHODS AND MATERIALS: A retrospective cohort analysis was performed of all patients treated with single-fraction lung SBRT at our institution from 2007 to 2022. Apical tumors were identified as those with an epicenter located above the arch of the aorta. Dosimetric analysis of dose to the brachial plexus (BP) was done using both the subclavian vessel (SCV) surrogate structure and anatomic BP. BPI was assessed per Common Terminology Criteria for Adverse Events, version 4.0, as regional paresthesia, marked discomfort and muscle weakness, and limited movement of the arm or hand. RESULTS: A total of 45 patients met inclusion criteria with median follow-up of 21 months. There were 9 patients who exceeded the BP dose constraint using the SCV or anatomic BP volume. Only 1 patient (2.2%) developed grade 2 BPI, occurring 7 months after SBRT. Dose to the anatomic BP for the affected patient was 26.39 Gy. For the entire cohort, the median SCV and anatomic maximum BP doses were 8.44 and 7.14 Gy, respectively. CONCLUSIONS: There is considerable variability in dose delivered to the BP after SBRT to apical lung tumors. BPI after single-fraction SBRT to apical tumors is rare and rates are comparable with those reported with multifraction regimens.