SMILE-stereotactic multiple fraction radiotherapy for non-spine bone metastases: study protocol for a multicenter, open-label phase III randomized controlled trial.

Background: The SMILE study addresses a significant need in palliative oncology by evaluating the non-inferiority of a shortened, 3-fraction stereotactic body radiotherapy (SBRT) schedule against the traditional 5-fraction approach for non-spine bone metastases in terms of pain control. Optimizing SBRT could significantly enhance the quality of life for patients by providing effective pain relief while minimizing treatment sessions.
Methods: This international, multicenter phase III trial will randomize 162 patients to receive either a 3-fraction regimen (9 Gy per fraction) or a standard 5-fraction regimen (7 Gy per fraction). Outcomes, assessed at 3 months post-treatment, will focus on pain response, quality of life, and control of metastasis. With a hypothesis-driven design, the study will incorporate intent-to-treat and per-protocol analyses, incorporating appropriate measures for data integrity and handling of missing information.
Discussion: If the 3-fraction SBRT regimen demonstrates non-inferiority, it could streamline palliative care protocols, reduce patient burden, and set a new standard for treatment, reflecting a patient-centered approach in palliative radiation oncology.
Trial Registration: The trial has been registered prospectively on ClinicalTrials.gov under the identifier NCT05406063, as of May 3, 2022.
Competing Interests: Declarations Ethics approval and consent to participate {24} Ethics approval has been obtained from Ethics Committee Zurich (BASEC2022 – 0063) and Bern. All methods are carried out in accordance with the current version of the World Medical Association Declaration of Helsinki and ICH-GCP guidelines as well as the local legally applicable requirements. All individual study participants will provide written informed consent to participate in the study. Consent will be obtained by study investigators in conjunction with clinical trials staff. Consent for publication {32} Not applicable—no identifying images or other personal or clinical details of participants are presented here or will be presented in reports of the trial results. The participant information materials and informed consent form are available from the corresponding author on request. Competing interests {28} The authors declare no competing interests.
(© 2024. The Author(s).)