Lung stereotactic body radiation therapy (SBRT) delivered over 4 or 11 days: A comparison of acute toxicity and quality of life

Purpose: The optimal duration over which lung SBRT should be delivered is unknown. We conducted a randomized pilot study in patients treated with four fractions of lung SBRT delivered over 4 or over 11 days. Methods: Patients with a peripheral solitary lung tumor (NSCLC or pulmonary metastasis), <= 5 cm were eligible. For NSCLC lung tumors <= 3 cm, a dose of 48 Gy in 4 fractions was used, otherwise 52 Gy in 4 fractions was delivered. Patients were randomized to receive treatment over 4 consecutive days or over 11 days. The primary end-point was acute grade >= 2 toxicity. Secondary end-points included quality of life (QOL) assessed using the EORTC QLQ-C30 and QLQ-LC13 questionnaires. Results: Fifty four patients were enrolled. More patients in the 11 day group had respiratory symptoms at baseline. 55.6% patients treated over 4 days and 33.3% of patients treated over 11 days experienced acute grade >= 2 toxicity (p = 0.085). Dyspnea, fatigue and coughing domains were worse in the 11 day group at baseline. At 1 and 4 months, more patients in the 4 day group experienced a clinically meaningful worsening in the dyspnea QOL domain compared to the 11 day group (44.5% vs 15.4%, p = 0.02; 38.5% vs 12.0%, p = 0.03, respectively). However, raw QOL scores were not different at these time-points between treatment groups. Conclusions: Grade 2 or higher acute toxicity was more common in the 4 day group, approaching statistical significance. More patients treated on 4 consecutive days reported a clinically meaningful increase in dyspnea, although interpretation of these results is challenging due to baseline imbalance between treatment groups. Larger studies are required to validate these results. (C) 2013 Elsevier Ireland Ltd. All rights reserved.