Conflicts of InterestJanet Brown has received speakers bureau honoraria from Novartis and Amgen and has served as a consultant and/or on advisory boards for Novartis, Amgen, Roche, and Bristol-Myers Squibb.Richard Cook has served as a consultant and/or on advisory boards for Novartis and Abbott.Allan Lipton has received commercial research grants from Novartis, Monogram Biosciences, and Oncogene Science; has received speakers bureau honoraria from Novartis, Amgen, and Genentech; has served as a consultant and/or on advisory boards for Novartis, Amgen, Galapagos, Acceleron Pharm, and has given expert testimony for Novartis.Luis Costa has received speakers bureau honoraria from Novartis and has served as a consultant and/or on advisory boards for Novartis and Amgen.Robert Coleman has received other commercial support from Novartis; speakers bureau honoraria from Novartis and Amgen; has served as a consultant and/or on advisory boards for Novartis, Amgen, Pfizer, and Roche; and has previously given expert testimony on the behalf of Novartis. Previously defined prognostic factors may not reflect current treatment standards and the use of antiresorptive therapies. We report a comprehensive multivariate analysis of potential prognostic factors for skeletal-related events (SREs) using data from a phase III, randomized study of zoledronic acid in patients with bone metastases from BC.
Methods:The trial evaluated the number and timing of SREs (pathologic fracture, palliative radiotherapy to bone, surgery to bone to treat or prevent a fracture, and spinal cord compression) and assessed variables for prognostic significance in univariate and multivariate Cox regression analyses. Continuous variables were categorized with predefined cutpoints. All associations with P < .05 were considered significant. A total of 444 zoledronic acid-treated patients with assessments of biochemical markers of bone metabolism and complete baseline variable data were included.Results: Significant baseline prognostic factors for occurrence of a first SRE by multivariate analyses included age, pain score, prior history of an SRE, predominant lesion type, elevated bone-specific alkaline phosphatase, and lactate dehydrogenase.Prior fracture was found to be prognostic in a reduced multivariate analysis of time to first fracture, but not for time to first palliative radiotherapy.
Conclusions:This model identified several prognostic factors that may be useful in routine clinical care. Validation of these factors in a separate dataset and generation of a prognostic risk score are recommended next steps.