Purpose: To evaluate trends in fractionation and cost of radiation for bone metastasis during a time period of multiple national quality improvement initiatives that focused on reducing the number of fractions per radiation episode.
Methods: Using nationwide Medicare claims from 2011 to 2014, we identified radiation episodes for bone metastasis from prostate, lung, and breast cancer. Details regarding fractionation, radiation therapy (RT) modality, and sociodemographic characteristics were abstracted from claims. Time trends in use of 10 or fewer RT fractions per episode were evaluated using the Cochran-Armitage test. Total cost per episode was calculated from a payer's perspective and reported in 2017 dollars; time trends in cost were assessed using linear regression. Generalized linear models identified predictors of treatment with 10 or fewer fractions.
Results: Of 51,533 episodes identified, 46,326 used 2D/3D RT, 3,199 used intensity-modulated RT, and 2,008 used stereotactic body RT. The proportion of 2D/3D RT episodes using 10 or fewer fractions increased from 65.5% to 79.7% ( Ptrend < .001), and mean total cost per episode decreased from $6,742 to $6,067 ( Ptrend < .001). Use of single-fraction radiation increased modestly for 2D/3D treatment (6.5% to 8.1%; Ptrend < .001). Predictors of 10 or fewer fractions included treatment in recent years, advanced age (≥ 85 years), and higher comorbidity score. Variation was noted based on geographic region and primary cancer.
Conclusion: During a period with quality initiatives launched by the American Society for Radiation Oncology, American Board of Internal Medicine, and National Quality Forum, use of 10 or fewer fractions for bone metastasis increased by 14.2%, but single-fraction regimens increased by only 1.6%, highlighting opportunities for quality improvement.