Progress in Shortening Treatment Courses for Bone Metastases in a Statewide Quality Consortium

A large body of research has studied various fractionation regimens for radiation therapy (RT) targeting bone metastases, with evidence that courses of 5 or fewer fractions are isoeffective compared with longer courses. We analyzed practice patterns within a statewide quality consortium following the implementation of quality measures promoting single-fraction RT (SFRT) for uncomplicated metastases and ≤5 fractions for all metastases.

Consecutive patients receiving RT for bone metastasis from primary breast, lung, melanoma, prostate, or renal cancer(s) between March 1, 2018, and December 31, 2024, were prospectively enrolled in a statewide quality consortium. SFRT and ≤5-fraction quality metrics were implemented on January 1, 2020, and January 1, 2022, respectively. Patient, treatment, physician, and facility characteristics were collected, and multivariable logistic regression, with and without random center intercepts, was used to account for clustering by center and to assess associations with metric adherence.

In total, 4477 patients were enrolled and received 6733 RT treatment plans, with 1105 patients receiving 1465 plans for uncomplicated metastases and 3247 patients receiving 4832 nonstereotactic body RT plans. The use of SFRT and ≤5-fraction RT for uncomplicated and any metastases increased from 17.8% to 38.8% and from 44.2% to 63.9%, respectively, after the implementation of quality measures. In both models, later years of treatment, longer distance to the treating facility, higher baseline fatigue, treatment site other than the spine, and fewer physician years in practice predicted shorter treatment courses. Patients with >1 site treated for uncomplicated metastases had lower odds of receiving SFRT. Forward planning, uncomplicated metastasis, retreatment, palliative intent, age ≥80 years, and an Eastern Cooperative Oncology Group performance status ≥2 independently predicted receipt of ≤5 fractions.

Our efforts to shorten treatment courses for bone metastases have been successful. The number and variety of factors that predict the use of shorter courses reflect the complexity of clinical decision-making in the treatment of bone metastases.