Purpose: To identify local and systemic risk factors for the development of pathologic fractures and determine the value of the Tokuhashi Score in patients with known asymptomatic lytic spinal metastases secondary to breast cancer.

Method: A prospective cohort study was carried out on 51 patients with lytic spinal metastases secondary to breast cancer identified as having either purely lytic or mixed disease. The Tokuhashi Score, developed to estimate life expectancy for patients with symptomatic spinal metastases being considered for surgery, was calculated for each of the 51 patients. The score consists of six parameters each of which is rated from 0–2. Initial and follow up CT images and pain and function data were obtained every four months for one year. A final review of patient charts was performed two years later to determine if each patient was still alive.

Results: Tumour burden was predominantly blastic and mixed rather than lytic. There was no progression of lytic tumour burden over the 12-month period, however there was progression of blastic tumour load. Eleven compression fractures occurred in seven patients; no burst fractures occurred during the study. No correlation between tumour burden (lytic, blastic or both) and risk of fracture was found. A weak correlation between bone mineral density and length of time elapsed from diagnosis of metastatic disease and fracture risk was found. Pain and functional data results were not related to tumour load. Tokuhashi score did correlate with survival, however actual survival in our population was far longer than that found in previous studies. Negative progesterone status was found to be negatively associated with life expectancy.

Conclusion: Metastatic vertebral disease in breast cancer patients has a predominantly blastic and mixed appearance with current pharmacologic therapies. Pathologic fracture risk appears to be more related to bone mineral density than tumour burden in this population. Tokuhashi score does correlate with life expectancy in patients with relatively asymptomatic spinal metastases. Having a progesterone receptor negative tumour has a significantly negative impact on life expectancy.