Split course palliative radiotherapy for advanced lung cancer with 3D planning based analysis of outcome: a retrospective review

Abstract

Background: Durable palliation of advanced lung cancer is a common objective for radiation oncologists.However, there is no consensus on how to deliver the radiation course. Herein we report our experience of using split course radiotherapy and our assessment of outcomes based on planning from three-dimensional (3D) simulation before each treatment course.Methods: All lung cancer patients from 2006-2020 were identified. Of these, 52 patients received a split course treatment of 50-60 Gy in 18-25 fractions intended to provide durable palliation for disease not amenable to curative therapy. Treatment involved 3D planning with repeat computed tomography (CT) simulation prior to the second course. Survival and symptomatic response were analyzed via chart review. We categorized rapid responders versus non-rapid responders from the initial radiation course based on ≥30% gross tumor volume (GTV) reduction at the second CT simulation. We evaluated the impact of response on overall survival and palliative response.Results: Among our cohort treated with split course palliative radiotherapy, 33 (63%) had a rapid response to initial treatment. There was no difference in survival between groups [hazard ratio (HR) =1.30, P=0.47].There was no significant difference in palliative response rates between rapid and non-rapid responders.On multivariable analysis, only female sex (HR =0.26, P<0.01) and receipt of systemic therapy following radiotherapy (HR =0.19, P<0.01) were associated with improved survival.Conclusions: There is currently significant practice pattern variability for palliative lung radiotherapy.Split course palliative radiation of 50-60 Gy in 18-25 fractions represents an option to consider for patients with advanced lung cancer who do not undergo definitive therapy and may benefit from a higher dose regimen. Our retrospective review suggests that rapid tumor response in a split course model does not predict survival or symptomatic response. Prospective studies are needed to further define which lung cancer patients may benefit from higher dose regimens.

Systemic therapy‐based split‐course stereotactic body radiation therapy

“…In addition to adjusting the target area based on volume changes, fractionated radiotherapy also allows for individualized adjustment of the intensity of the radiotherapy schedule based on patient tolerance and disease response. In advanced lung cancers 95 or head and neck cancer, 96 split‐course SBRT delivers two courses of radiation separated by 4–6 weeks, offers an attractive treatment paradigm to personalize radiation intensity based on patient tolerance, while maintaining reasonable safety and efficacy in those unfit for standard full course radiotherapy. Through split‐course SBRT, adaptive radiotherapy can be effectively implemented to further reduce normal tissue damage and improve the patient's tolerance to treatment, thus guaranteeing the combination of high‐intensity radiotherapy and systemic therapy.…”

“…93,94 In addition to adjusting the target area based on volume changes, fractionated radiotherapy also allows for individualized adjustment of the intensity of the radiotherapy schedule based on patient tolerance and disease response. In advanced lung cancers 95 induce endothelial cell death. [97][98][99] Excessive vascular damage can affect blood perfusion in solid tumors; however, the split-course SBRT treatment modality can give time to restore blood perfusion during intervals, thereby reducing hypoxia-induced radioresistance while restoring transport to drugs and immune cells.…”