OBJECTIVEThe aim of this study was to access the relationship of osteolytic bone metabolic markers such as serum type I collagen carboxy-terminal telopeptide (sICTP), N-terminal cross-linked telopeptides of type I collagen (uNTx), urinary pyridinoline (uPyd) with the therapeutic effect in breast cancer patients with bone metastases.

METHODS120 patients with breast cancer were included in this study. The levels of sICTP, uNTx and uPYD were measured by ELISA assay. The differences were compared between patients with and without bone metastasis. The patients with bone metastasis were treated and followed up as clinically indicated.

RESULTSThe levels of all above mentioned biomarkers in patients with bone metastasis were significantly higher than that in patients without bone metastasis (P < 0.01). A significant correlation was found between each two markers (r > 0.5, P < 0.01). The biomarkers were examined again in 45 patients with bone metastasis after treatment to evaluate the treatment response. The median follow-up was 10 months. Based on clinical evaluation criteria, 25 patients were responders and 20 were non-responders. For responders, after 3 months treatment, the levels of the three bone markers were significantly reduced (P = 0.025, P < 0.001, P < 0.001). But for non-responders, with progression of bone lesions, the levels of the three markers were significantly raised (P = 0.011, P = 0.002, P = 0.002). By means of multiple logistic regression with stepwise selection, the uPyd and uNTx activities were closely correlated with treatment response (OR = 17.0, P = 0.019; OR = 16.7, P = 0.015), however, the sICTP did not show any correlation with treatment response P = 0.841).

CONCLUSIONThe levels of sICTP, uNTx and uPyd may be used as indicators in assessment of the effect of antiresorptive treatment and evaluation of prognosis in breast cancer patient with bone metastases.