Breast cancer and bone metastases: the association of axial skeleton MRI findings with skeletal-related events and survival.

The purpose of this study was to determine if bone metastasis characteristics on axial skeleton MRI are associated with either skeletal-related events (SREs) or survival in breast cancer patients. A retrospective review was performed on 247 breast cancer patients with bone metastases identified on axial skeleton MRI. MRI studies were reviewed for metastases T1 signal, signal uniformity, complete vertebral metastatic marrow replacement, metastases quantity, and distribution. Odds ratio (OR) and hazard ratios (HR) were calculated, with 95 % confidence intervals (95 % CI), to determine association with either future SREs or survival. At the time of analysis, 174 (70 %) patients had developed SREs and 176 (71 %) patients were dead. Features of skeletal metastases associated with SREs included the presence of complete metastatic marrow replacement within any vertebra; OR 2.363 (95 % CI 1.240-4.504, P = 0.0090), and more widely distributed metastases; OR 1.239 (95 % CI 1.070-1.435, P = 0.0040). Features associated with shorter survival included the presence of complete metastatic marrow replacement within any vertebra; HR 1.500 (95 % CI 1.105-2.036, P = 0.0093), and more widely distributed metastases; HR 1.141 (95 % CI 1.047-1.243, P = 0.0027). Metastases T1 signal, signal uniformity, and surprisingly quantity were not associated with SREs or survival. Axial skeleton MRI was able to identify characteristics predictive of future SREs and survival. These characteristics could be used for risk stratification for future trials if prospectively validated.