Introduction Lung cancer is a disease which, despite the advancements in treatment, still has a very poor 5-year survival rate. Stereotactic ablative radiation therapy (SABR) is a highly advanced, sophisticated, and safe treatment which allows patients with early stage lung cancer to be treated effectively without invasive procedures and with excellent clinical outcomes. Avoiding surgery minimises morbidity and recovery time, bettering patients' quality of life. Furthermore, SABR allows patients unsuitable for surgery to still undergo curative treatment. Methods We aimed to review SABR-related normal tissue toxicities reported in the literature. While many studies assess safety, clinical efficacy, and disease control of SABR for lung cancer, the number of comprehensive reviews that analyse SABR-related side-effects is scarce. This integrative review summarises the toxicities reported in literature based on published clinical trials and tumour location (central or peripheral tumours) for available SABR techniques. Given that the majority of the clinical studies did not report on the statistical significance (e.g., p-values and confidence intervals) of the toxicities experienced by patients, statistical analyses cannot be performed. As a result, adverse events are compiled from clinical reports; however, due to various techniques and nonstandard toxicity reports, no meta-analysis is possible at the current stage of reported data. Results When comparing lobectomy and SABR in phase III trials, surgery resulted in increased procedure-related morbidity. In phase II trials, very few studies showed high grade toxicities/fatalities as a result of SABR for lung cancer. Gross target volume size was a significant predictor of toxicity. An ipsilateral mean lung dose larger than 9 Gy was significantly associated with radiation pneumonitis. Conclusions Based on the studies reviewed SABR is a safe treatment technique for lung cancer; however, further well-designed phase III randomised clinical trials are required to produce timely conclusive results and to enable their comparison and statistical analysis.

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Stereotactic ablative radiation therapy for lung cancer is an advanced technique where tumours are ablated with hypofractionated radiation doses, with a high degree of accuracy. The aim of this paper is to review the available literature and to discuss the SABR-induced toxicities for lung malignancies as a function of radiation delivery technique. A Medline search was conducted to identify the appropriate literature to fulfil the aim of this review and data from all applicable papers were collated and analysed. The most common techniques of SABR delivery employ linear accelerators, CyberKnife robotic radiosurgery system, TomoTherapy and the Novalis beam surgery system. Linear accelerator-based treatments give rise to a variety of toxicities that are strongly dependent on both patient-related factors and planning/dosimetry-related factors. The limited number of studies using CyberKnife reported low grade toxicities. Grade three toxicities mainly include fatigue and chest pain, usually in less than 10% of patients. All treatment techniques presented show efficiency in SABR delivery with various toxicities which, at this stage, cannot render one technique better than the other. For more conclusive results, well-designed phase three randomised clinical trials are required with better patient selection criteria, including dose and fractionation, treatment machine and technique, along with the consistent selection of a common toxicity grading criterion.