Luke Higgins, MD
University of Michigan
Ann Arbor, MI
Purpose/Objective(s):
Radiotherapy (RT) is an effective and standard treatment for bone metastases. While data supporting the superiority of treatment with > 5 fractions for any and > 1 fraction for uncomplicated bone metastases are limited, longer treatment courses are routinely used. We report our ongoing efforts to promote use of shorter treatment courses within a statewide quality consortium.
Materials/
Methods:
Consecutive patients receiving RT for bone metastases from primary breast, lung, melanoma, prostate, or renal cancer(s) between 3/1/18 and 6/30/23 were prospectively enrolled in the Michigan Radiation Oncology Quality Consortium database. Quality metrics promoting use of single fraction RT for uncomplicated bone metastases and ≤5 fraction RT for all bone metastases were introduced in 1/1/20 and 1/1/22, respectively. Uncomplicated metastases were defined as painful, not previously irradiated, and not associated with spinal cord or nerve root compression, fracture, surgery, or a soft tissue component. SBRT plans were excluded from the ≤5 fraction analysis given that all were ≤5 fractions. Patient, treatment, physician, and facility characteristics were captured. Mixed models with a random intercept for centers were generated with significance defined as p<0.05.
Results:
In total, 2,700 patients were enrolled across 29 treatment facilities. Among all patients, 1890 of 3760 (50.3%) unique treatment plans were delivered in ≤5 fractions. From 2018 to 2023, observed annual rates of ≤5 fraction regimens increased from 32% to 67%. Among 825 patients treated for uncomplicated metastases, 327 of 1089 (30%) unique treatment plans utilized a single fraction. From 2018 to 2023, observed annual rates of single fraction use increased from 15% to 40%. Significant predictors of ≤5 fraction use and single fraction use are summarized in Table 1.
Conclusion:
Our efforts to shorten treatment courses for bone metastases in our statewide quality consortium have been successful. The number and variety of factors that predict the use of shorter courses highlight the complexity of the decision making when treating these patients.
Table 1:
| ≤5 Fractions | Variable | OR | 95% CI | P-value | Single Fraction | Variable | OR | 95% CI | P-value |
| Year | 1.71 | 1.52 - 1.92 | <0.01 | Year | 2.56 | 1.65-3.97 | <0.01 | ||
| Age ≤59 ≥70 | - 1.81 | - 1.23-2.67 | - <0.01 | Primary Malignancy Lung Breast | - 0.20 | - 0.05-0.74 | - 0.02 | ||
| Treatment Intent: Palliation Durable Local Control Existing Pathologic Fracture Cord Compression | - 0.44 0.21 0.46 | - 0.29-0.66 0.12-0.36 0.23-0.92 | - <0.01 <0.01 0.03 | Physician Years in Practice 0-10 Years >30 Years | - 0.18 | - 0.03-0.93 | - 0.04 | ||
| Treatment Site Spine Other | - 2.52 | - 1.97-3.24 | - <0.01 | Treatment Site Spine Other | - 9.035 | - 3.50-23.3 | - <0.01 | ||
| ECOG 0-1 ≥2 | - 1.66 | - 1.22-2.27 | - <0.01 | ||||||
| ≥2 Regions Treated | 1.53 | 1.15-2.03 | <0.01 | ||||||
| Uncomplicated | 1.72 | 1.24-2.40 | <0.01 | ||||||
| Opioid Use | 1.53 | 1.08-2.15 | 0.02 | ||||||
| Academic Practice Setting | 1.65 | 1.18-2.30 | <0.01 |