Cross-linked type I collagen C- and N-telopeptides in women with bone metastases from breast cancer

This study documents values of biochemical markers of bone remodeling in 10 6 patients with breast cancer. Based on scintigraphic and radiological find ings, patients were divided into 3 groups: 19 patients with bone metastases , 65 patients without bone metastases and normal bone scintigrams, and 22 p atients with pathological, non-malignant findings on scintigraphy without p roof of bone metastases. Urinary cross-linked type I collagen N-telopeptide s (NTx) and serum cross linked type I collagen C-telopeptides (ICTP) were a ssessed as markers of bone resorption. Bone alkaline phosphatase (BAP) was assessed as a marker of bone formation. All three markers were significantl y higher in patients with bone metastases compared to both patients without skeletal recurrence and those with pathological, non-malignant scintigraph ic findings (p < 0.01). There were no statistically significant differences between the latter two groups. The clinical sensitivity for diagnosing bon e metastases was 44% for NTx, 65% for ICTP, and 26% for BAP, respectively. The clinical specificitiy for discriminating patients with bone disease fro m those without were 79%. 91%, and 92% for NTx, ICTP, and BAP, respectively . In conclusion, markers of bone remodeling are increased in patients with breast cancer metastatic to the skeleton. The sensitivity of the markers pr esented in this paper did not seem to be sufficient enough for early identi fication of patients with subclinical bone recurrence in a clinical practic e setting.