Radiotherapy for osteoblastoma: the 25-year institutional experience.

Background: Osteoblastoma (OB) is a rare benign bone tumor, mainly affecting adolescents and young adults. It's commonly found in the spine and long bones, with a male-to-female ratio of 2:1. Surgery, primarily en bloc resection or curettage, is the main treatment. Radiotherapy (RT) or systemic treatment is considered in specific cases. However, optimal RT strategies remain unclear due to limited and outdated data. This study aims to evaluate RT role, efficacy, and safety in treating OB. Matrials and methods: The study group was a cohort of consecutive patients with OB treated in our institute that received RT in years 1998-2023. We analyzed indication for RT, irradiated site, RT technique, total dose, dose per fraction, early and late tolerance, and survival. Results: Thirteen patients meeting the criteria were analyzed. Most were males (10 out of 13) with a median age of 21. Most OBs were within the vertebral column. All patients received definitive RT for unresectable disease and underwent conventionally fractionated RT (1.8-2.0 Gy per fraction) to total doses 40-70.2 Gy. Only mild acute toxicity was observed. No late toxicity was reported. The median follow-up was 118 months. Local progression was observed in four patients, all of whom died. Conclusions: RT is a valuable option for certain OB patients ineligible for surgery. Seeking treatment at specialized bone tumor centers with RT techniques is crucial due to OB's rarity and the lack of standardized guidelines. Recommended RT doses fall between 50-70 Gy using intensity-modulated techniques in conventional 1.8-2 Gy fractions.