Serum markers of bone metastases in postmenopausal breast cancer patients treated with formestane.

Bone metabolism marker evaluation is expected to play an auxiliary role in the diagnosis and follow-up of bone metastases in patients affected by different types of neoplasms. In this study we have evaluated osteoblastic and osteoclastic markers in 18 patients with bone metastases from breast cancer at diagnosis and for 1 year of follow-up during treatment with the aromatase inhibitor formestane. Osteoblastic markers include the carboxy-terminal propeptide of type I procollagen, the bone-specific alkaline phosphatase and the bone GLA protein. The carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) was evaluated as a marker of osteoclastic activity. The patients were classified into three groups according to clinical response. A good correlation between marker level modifications and clinical evolution of skeletal metastases was observed for all the examined markers. Patients with progressive disease showed increasing levels of all markers, whereas patients in regression showed a reduction compared to the basal levels; patients with stable disease fell in between these two categories. We also found that basal ICTP values have prognostic significance: in the stable and progressive disease group they were higher than in the partial response group.