Multi-institutional analysis of stereotactic body radiation therapy for operable early-stage non-small cell lung carcinoma.

Abstract

Although stereotactic body radiation therapy (SBRT) is the standard of care for inoperable early-stage non-small cell lung carcinoma (NSCLC), its role for medically operable patients remains controversial. To address this knowledge gap, we conducted a multi-institutional study to assess post-SBRT disease control and survival outcomes in medically operable patients. We conducted a retrospective cohort study including patients with biopsy-proven cT1-2N0M0 NSCLC treated with definitive SBRT (2006-2015). Per patient charts, inoperability referred to documentation of poor surgical candidacy with a given rationale for lack of resection. Charts of operable patients contained documentation of patients refusing surgery or choosing SBRT, without a documented rationale for inoperability. Subjects were excluded in cases of ambiguity regarding the aforementioned definitions and/or lack of clearly documented operability status. Endpoints included local failure (LF) and regional-distant failure, both evaluated with Fine and Gray competing risks regression; Kaplan-Meier methodology analyzed overall survival (OS) and progression-free survival (PFS). Of 952 patients, 408 (42.9%) were operable, and 544 (57.1%) were inoperable. Median follow-up was 22 months. Two-year LF was 9.7% in operable patients and 8.2% in inoperable patients (p = 0.36). There was no statistical difference in regional-distant failure (p = 0.55) between cohorts. Operable patients experienced statistically higher OS (p = 0.04), but not PFS (p = 0.11). Respective 1-, 2-, and 3-year OS in operable patients were 85.4%, 66.2%, and 51.2%. Although patients with operable NSCLC experience higher OS than their inoperable counterparts, disease-related outcomes are similar. These results may better inform shared decision-making between medically operable patients and their multidisciplinary providers.