Background: Bone metastases belong to the most frequent metastases in breast cancer. Currently there exist no serum markers which allow early detection of bone metastases.
Patients and methods: 89 patients with primary breast cancer have been investigated for parathyroid-hormone-related peptide (PTHrP) in the tumour and bone sialoprotein (BSP) in the serum. Both markers have been correlated with classical prognostic factors and survival.
Results: The median age of the patients was 56 years. 17 of the 89 patients developed bone metastases and 25 died during the observation period of 5 years. PTHrP correlated significantly with bone metastases free survival (p = 0.0004) and overall survival (p = 0.0005), whereas BSP correlated only with the bone metastases free survival (p = 0.03). Both markers were shown to be independent prognostic factors for the bone metastases free survival in the multivariate analysis. PTHrP was also found to be an independent prognostic factor for the overall survival.
Conclusion: The investigation of PTHrP could be a prognostic marker for the presence of bone metastases while BSP could be a marker for the early detection of bone metastases.