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

ABSTRACT

PURPOSE: Non-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 8 fractions in large-volume local recurrences. METHODS AND MATERIALS We conducted a 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 8 fractions using the 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. RESULTS: Seven patients met inclusion criteria. Median follow up time was 38 months (18.1-72.4). Median age was 67 years (63-80). Median time to reirradiation was 18.2 months (7.3-28.6). Retreatment median ITV was 57.9 cc (15.8-344.6), and PTV median was 113.6 cc (38.3-506.9). Local control was maintained in 4 of 7 patients (57.1%). Two of the 7 patients (28.6%) remained alive. Median disease-free interval was 22.5 months (11-65). Three of 7 patients (42.9%) had grade 2 toxicities. One patient (14.3%) had a grade 3 rib/chest wall toxicity with concurrent disease recurrence invading the chest wall. CONCLUSION: This study reports that SBRT of 60 Gy in 8 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 systemic therapy.