There are many reports suggesting that the levels of bone turnover markers (BTM) might be correlated with skeletal-related-events and disease progression in breast cancer patients with bone metastases (BM). We therefore evaluated the correlations OS with the changes in urinary N-telopeptide of type I collagen (u-NTX) in breast cancer patients with BM treated with denosumab (Dmab).
34 patients were enrolled in this study. All patients received Dmab 120 mg subcutaneously every month and u-NTX was checked at baseline and 1 month after Dmab was administered. We calculated the percentage change of u-NTX level (u-NTX%) [(baseline u-NTX level – 1-month u-NTX level)/baseline u-NTX level] and established a cut-off value by using receiver operating characteristic analysis. OS was defined as the time interval from Dmab administration to the date of death. The patients were divided into two groups by using the cut-off value, and OS was evaluated using the Kaplan-Meier method and analyzed by a log-rank test.
According to the immunohistochemical analysis, estrogen receptor positive and human epidermal growth factor receptor 2 negative (ER+/HER2-) profile was observed in 22 patients, while ER+/HER2+, ER-/HER2+, and ER-/HER2- profiles were observed in 4, 2, and 6 patients, respectively. 2 patients had oligo-BM and 32 patients had multiple-BM. The mean u-NTX% was 0.63 and the established cut-off value was 0.669. The u-NTX% in 19 patients was >0.669 (high u-NTX group) while the remaining 15 patients had u-NTX% under 0.669 (low u-NTX group). OS in the high u-NTX group (
High u-NTX% in early phase of treatment could be a promising finding for OS in breast cancer patients with BM treated with Dmab.
Department of Breast Surgery, Yokkaichi Municipal Hospital
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All authors have declared no conflicts of interest.