Sensitivity and specificity of serum cross-linked N-telopeptides of type 1 collagen (NTx) in patients with solid tumors

Abstract

Objective: Cross-linked N-telopeptides of type I collagen (NTx) increase in situations in which bone resorption is increased, such as osteoporosis and bone metastasis. It was evaluated the usefulness of NTx for the diagnosis of bone metastases in patients with solid tumors. Methods: It was conducted a prospective study, at a tertiary public hospital. A quantitative enzyme-linked immunosorbent assay (ELISA) assay of serum NTx levels in 19 subjects without a history of cancer and 62 patients with various solid tumors referred for a bone scan was evaluated. Three specialists read all bone scans. Rresults: It was not found any significant correlations between serum NTx and age, sex, history of bone pain, tumor type and bone alkaline phosphatase levels. We found a significant correlation between serum NTx and alkaline phosphatase levels (r2 = 0.08, p = 0.022). Serum NTx sensitivity, specificity, positive and negative predictive values and area under the receiver operating characteristic (ROC) curve for the presence of bone metastases were 0.34, 0.92, 0.95, 0.22 and 0.59, respectively. Cconclusions: It was concluded that serum levels of NTx are highly sensitive for the diagnosis of bone metastases in patients with solid tumors.

Keywords

• Alkaline phosphatase
• Bone neoplasms
• Predictive value of tests
• Collagen type I