Radiation-induced toxicity after image-guided and intensity-modulated radiotherapy versus external beam radiotherapy for patients with spinal bone metastases (IRON-1): a study protocol for a randomized controlled pilot trial

BACKGROUND Radiation therapy (RT) of bone metastases provides an important treatment approach in palliative care treatment concepts. As a consequence of treatment, the extent of radiation-induced toxicity is a crucial feature with consequences to a patient's quality of life. In this context this study aims at reducing the extent of radiation-induced side effects and toxicity by assuming a better sparing of normal tissue with the use of intensity-modulated instead of conventionally delivered external beam radiotherapy. METHODS/DESIGN In this prospective, randomized, single-center trial for patients with spinal bone metastases, RT is performed as either image-guided intensity-modulated radiotherapy (10x3Gy) or conventionally fractionated external beam radiotherapy (10x3Gy). Afterwards radiation-induced toxicity will be assessed and compared 3 and 6 months after the end of radiation. DISCUSSION The aim of this pilot study is the evaluation of achievable benefits, with reduced radiation toxicity being the primary endpoint in the comparison of intensity-modulated radiotherapy versus conventional radiotherapy for patients with spinal bone metastases. Secondarily, bone re-calcification, quality of life, pain relief, spinal instability, and local control will be measured and compared between the two treatment groups. TRIAL REGISTRATION ClinicalTrials.gov, NCT02832830 . Registered on 12 July 2016.