Comparison of urinary markers for bone resorption in multiple myeloma.

Multiple myeloma causes extensive bone remodeling. Classical biochemical markers such as urinary calcium have poor sensitivity for detecting multiple myeloma bone remodeling. New biochemicals have been developed including a carboxyterminal telopeptide of collagen I (CTX). We used an immunoenzymatic assay to determine urinary CTX in 60 patients with multiple myeloma. This marker was evaluated with regard to total pyridinolines, urinary calcium, radiological features, pain and response to treatment with bisphosphonates. In patients with bone involvement, CTX concentrations were significantly higher (+230%) than those of deoxypyridinoline (DPD) (+175%) and pyridinolines (PYD) (+130%). In all patients we have found a close correlation between CTX and DPD but not between CTX and PYD. Compared to radiological features, CTX was more sensitive (97%) and specific (96%) than DPD. After treatment by bisphosphonates, the fall in CTX concentrations was paralleled to urinary calcium and more marked than pyridinolines. Although our results need to be confirmed, CTX appears to be a potential marker to explore bone involvement in multiple myeloma.

Urinary carboxyterminal telopeptide of collagen I as a potential marker of bone metastases chemotherapy monitoring in breast cancer.

Breast cancers frequently have osteoclastic bone metastases that are difficult to monitor and treat. Bone scintigraphy with 99mTc-labeled biphosphonates is still the reference method for detecting and localizing bone involvement. Classical biochemical markers such as urinary calcium have poor sensitivity for detecting and monitoring metastases of breast cancers. New biochemical markers for the study of bone remodeling have recently been developed, including a degradation product of the C-terminal end of the telopeptide of type I collagen (CTX). We used an immunoenzymatic assay technique for urinary CTX in 84 pre- and post-menopausal women and demonstrated a correlation between scintigraphic scores and urinary CTX concentrations. CTX values are significantly different between the control group and patients with bone metastasis, except those with score 0. There is a regular increase in urinary CTX concentration from score 0 (no abnormal uptake) to score 4 (diffuse carcinomatosis). There is no significant variation between control population and score 0 to 3 for urinary calcium. Only women with scintigraphic score 4 have significantly increased urinary calcium concentrations. Measuring CTX in pre- and post-menopausal patients during breast cancer chemotherapy might be of great interest for monitoring the development of metastases and the therapeutic efficacy of chemotherapy.