Thoracic Reirradiation with Stereotactic Body Radiation Therapy (SBRT) for Recurrent Advanced Non-Small Cell Lung Cancer (NSCLC)

Abstract

BackgroundNon-small cell lung cancer (NSCLC) local control remains suboptimal with rates around 75%. Stereotactic body radiation therapy (SBRT) is an option for isolated local recurrences of small volume recurrences. This study investigates the safety and efficacy of 60 Gy in eight fractions in large volume local recurrences. MethodsA retrospective chart review of patients treated with salvage SBRT for NSCLC lung parenchymal recurrence between July 2013 and February 2020. Reirradiation prescribed dose was 60 Gy in eight fractions utilizing SBRT technique. The primary endpoint was local control at most recent follow-up or death. Secondary endpoints included overall survival, disease-free interval, cancer-specific survival, and treatment related toxicities. ResultsSeven patients met criteria. Median follow up time was 38 months (18.1-72.4). Median age was 67 years (63-80). The median time to reirradiation was 18.2 months (7.3-28.6). Retreatment median ITV was 57.9cc (15.8-344.6) and PTV median was 113.6cc (38.3-506.9). Local control was maintained in four of seven patients (57.1%). Two of the seven patients (28.6%) remained alive. Median disease-free interval was 22.5 months (11-65). Three of seven patients (42.9%) had grade two toxicities. One patient (14.3%) had a grade 3 rib/chest wall toxicity with concurrent disease recurrence invading the chest wall. ConclusionThis study reports that SBRT of 60 Gy in eight fractions was delivered safely and effectively to large volume recurrent NSCLC previously treated with radiation therapy. The disease-free interval of nearly 2 years is meaningful for patients’ quality of life and duration of time off of systemic therapy.