Purpose: Radiation therapy is one of the mainstays of treatment for painful bone metastases; however, the optimal fractionation and dosing of radiation for a given patient and disease characteristics are still subject to debate.
Methods and materials: We retrospectively examined 475 patients who received radiation for bone metastases at our institution from 2009 through 2014 and evaluated survival outcomes based on parameters of their first treatment course and patient demographics. Kaplan-Meier analysis was used to analyze factors associated with overall survival (OS). A recursive partition analysis (RPA) was used to generate a decision tree of patient characteristics resulting in significant differences in survival. A Cox model was used to verify the RPA and evaluate the significance of biologically equivalent dose (BED) along with other factors.
Results: In our cohort, median age was 62 years and median Karnofsky performance status (KPS) was 70. Survival time by primary tumor type: breast (median, 35.9 months), prostate (12.8 months), other (median, 11.0 months), lung (median, 5.3 months), and gastrointestinal (median, 4.0 months) (P < .0001). Primary tumor type and KPS significantly affected survival, whereas age was also significant for survival in certain primary tumor types. Pain control was not found to be significantly affected by primary tumor type (P = .72) or BED (P = .14).
Conclusion: Our data demonstrate that selection of radiation fractionation schedules should take into account primary tumor type, KPS, and age, and we have generated an RPA model including these factors to help guide decision making. We also found that shorter fractionation schedules are as effective as longer fractionation schedules for pain control, regardless of primary tumor type.
Copyright © 2017 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.