Variation in the Use of Single- Versus Multifraction Palliative Radiation Therapy for Bone Metastases in Australia

Purpose: To evaluate the use of single-fraction palliative radiation therapy (SFRT) for the management of bone metastases (BM) in Victoria, Australia. Methods and Materials: This is a population-based cohort of patients with cancer who received radiation therapy for BM between 2012 and 2017 as captured in the Victorian Radiotherapy Minimum Data Set. The primary outcome was proportion of SFRT use. The Cochrane-Armitage test for trend was used to evaluate changes in practice over time. Multivariable logistic regression was used to assess factors associated with SFRT use. Results: Of the 18,158 courses of radiation therapy for BM delivered to a total of 10,956 patients, 17% were SFRT. There was no significant change in SFRT use over time, from 18% in 2012 to 19% in 2017 (P =.07). SFRT was less commonly given to the skull (4%) and spine (14%), compared with the shoulder (37%) and ribs (53%). Patients with lung cancer (21%) were most likely to receive SFRT, followed by those with prostate cancers (18%) and gastrointestinal cancers (16%). Patients from regional/remote areas were more likely to have SFRT compared with those in major cities (22% vs 16%, P <.001). Patients treated in public institutions were more likely to have SFRT compared with those treated in private institutions (22% vs 10%, P <.001). In multivariable analyses, increasing age, lung cancer, higher socioeconomic status, residence in regional/ remote areas, and being treated in public institutions were factors independently associated with increased likelihood of receiving SFRT. Conclusions: SFRT appears underused for BM in Australia over time, with variation in practice by patient, tumor, sociodemographic, geographical, and institutional provider factors.