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.