(P105) Community-Based Early-Stage Treatment (BEST) Outcomes for NSCLC

April 30, 2015

LC, survival, and toxicity of stage I NSCLC treated with SBRT in this community setting are comparable to those reported in university and multi-institutional trials. The efficacy, safety, and convenience of SBRT have been translated to a large cohort of patients in an outpatient community cancer center. These results also indicate that doses < 60 Gy delivered in five fractions may be less effective at achieving LC. As lower doses are examined in central lesions, it will be important to closely evaluate any possible reduction in LC.

Austin N. Arnone, BS, Christopher Biggs, MD, PhD, Daniel Reed, DO, Terry Lee, MD, Cheri Pantoja, CCRP, Kevin Rogers, MS; Arizona Center for Cancer Care

PURPOSE/OBJECTIVES: Stereotactic body radiation therapy (SBRT) has been established as an effective treatment for early-stage non–small-cell lung cancer (NSCLC) in patients who are medically inoperable or refuse surgery. This retrospective study analyzes outcomes of lung SBRT in the setting of a community-based cancer treatment center in Arizona.

MATERIALS AND METHODS: Between 2008 and 2013, a total of 146 tumor sites in 126 patients with stage I NSCLC were definitively treated using SBRT administered via the Varian RapidArc, a continuous dynamic IMRT system with cone-beam computed tomography (CT) localization. Simulation was gated, and treatment targeted a static volume. Patients were determined to be medically inoperable (n = 96) or refused surgery (n = 30). Treatment was delivered using a risk (tumor site, size)-adapted dose of 60 Gy (73 sites), 55 Gy (4 sites), or 50 Gy (52 sites) or a lower dose (17) in five fractions. Treatment outcomes were interpreted using Kaplan-Meier analysis of overall survival (OS), local control (LC), and disease-free survival (DFS). Correlation of patient, tumor, and treatment factors with survivability was analyzed using Cox proportional hazards.

RESULTS: Median age was 78 years; 44 patients were male, and 82 were female. The 3-year OS for all patients was 76%, with a median follow-up of 20 months (range: 2–67 mo). Median OS was 57 months. The 3-year LC for the entire cohort was 90.5%, and 3-year DFS was 68%. The 10 sites that developed local recurrence all received less than 60 Gy, yielding a 3-year LC of 81.7% for this subgroup (n = 65). Currently, LC is 100% for sites receiving 60 Gy (n = 73). Multivariate analysis demonstrated that no patient, tumor, or treatment factor was significantly predictive of survival. There was a 7.1% rate of grade 3 toxicity by Radiation Therapy Oncology Group (RTOG) criteria, with no grade 4 or 5 toxicities within 90 days of treatment.

CONCLUSIONS: LC, survival, and toxicity of stage I NSCLC treated with SBRT in this community setting are comparable to those reported in university and multi-institutional trials. The efficacy, safety, and convenience of SBRT have been translated to a large cohort of patients in an outpatient community cancer center. These results also indicate that doses < 60 Gy delivered in five fractions may be less effective at achieving LC. As lower doses are examined in central lesions, it will be important to closely evaluate any possible reduction in LC.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org