212 - Predictors of Skeletal-Related Events and Quality of Life Dimensions among Patients with High-Risk, Asymptomatic Bone Metastases with or without Early Radiation Therapy: Secondary Analysis of a Multicenter, Randomized Phase II Clinical Trial
Presenter(s)
K. Lapen1, Z. Zhang2, C. White2, C. A. Barker3, R. Kotecha4, A. F. McIntosh5, P. Iyengar1, J. T. Yang6, D. Yerramilli1, and E. F. Gillespie7; 1Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, 2Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, 3Memorial Sloan Kettering Cancer Center, New York, NY, 4Miami Cancer Institute, Baptist Health South Florida, Miami, FL, 5Department of Radiation Oncology, Lehigh Valley Cancer Institute, Allentown, PA, 6Department of Radiation Oncology, NYU Langone Health, New York, NY, 7Department of Radiation Oncology, University of Washington, Seattle, WA
Purpose/Objective(s): Early radiation therapy (RT) reduces the rate of skeletal-related events (SRE) which can affect patients’ functionality and quality of life (QOL). We aimed to determine predictors of SRE and the effect of early RT on individual QOL dimensions.
Materials/Methods: We conducted a secondary analysis of a multicenter, randomized phase II trial (NCT03523351) of early RT to asymptomatic, high-risk bone metastases versus observation. A competing risks analysis of time to SRE was performed to assess patient-level factors associated with SRE. Linear mixed models were used to evaluate dimensions of the EuroQol 5-Dimension 5-Level (EQ-5D-5L) QOL assessment (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) over time by study arm.
Results: Overall, 78 patients with 122 bone metastases were enrolled; 71 patients (91%) were evaluable for the primary endpoint of SRE (35 patients in the early RT arm vs. 36 patients in the control arm). A total of 15 SRE occurred among 11 unique patients during the one-year follow-up period. Receipt of early RT was statistically significantly correlated with a lower risk of SRE (HR 0.09, 95% CI 0.01-0.66, p=0.018), while age, race, gender, performance status, primary cancer type, disease burden, and the use of bone-modifying agents were not. The difference in individual EQ-5D-5L dimensions at each time point are depicted in the table. In the linear mixed model predicting self-care, the interaction between time and study arm was statistically significant (p=0.022). At six months, the control arm had a decline in self-care, while patients in the RT arm had an improvement. Anxiety/depression was worse at three months in the RT arm, but this was not statistically significant (p=0.120).
Conclusion: Rates of SRE are high among patients with bone metastases and these findings underscore the importance of early RT in their prevention. Patient-reported QOL suggests preservation of self-care with early RT, and that survival beyond six months may be needed to observe a benefit. Further research regarding patient selection and the impact of SRE on QOL and functionality are needed, and a phase III randomized trial (NRG CC014, NCT06745024) is in progress.
Abstract 212 - Table 1| Dimension | Time Point * Study Arm | Beta1 | 95% CI | P-Value |
| Mobility | 3 Months | -0.02 | -0.66, 0.62 | 0.270 |
| 6 Months | -0.46 | -1.1, 0.21 | ||
| 1 Year | -0.71 | -1.6, 0.18 | ||
| Self-Care | 3 Months | 0.02 | -0.49, 0.52 | 0.022 |
| 6 Months | -0.71 | -1.3, -0.18 | ||
| 1 Year | -0.59 | -1.3, 0.12 | ||
| Usual Activities | 3 Months | 0.22 | -0.54, 0.98 | 0.498 |
| 6 Months | -0.35 | -1.1, 0.46 | ||
| 1 Year | -0.44 | -1.5, 0.62 | ||
| Pain/Discomfort | 3 Months | 0.04 | -0.59, 0.67 | 0.295 |
| 6 Months | -0.49 | -1.20, 0.17 | ||
| 1 Year | -0.54 | -1.40, 0.34 | ||
| Anxiety/Depression | 3 Months | 0.32 | -0.22, 0.87 | 0.117 |
| 6 Months | -0.30 | -0.88, 0.28 | ||
| 1 Year | -0.48 | -1.2, 0.28 | ||
| 1Estimates represent the interaction between study arm and time. Main effects are not shown. | ||||