ABSTRACT
Objective To explore the value of urinary N-terminal telopeptide of type Ⅰ collagen (uNTX) combined with bone scintigraphy (BS) for the diagnosis of bone metastases.Methods A total of 227 patients suspected of bone metastases by BS were selected from Jan to May of 2012.UNTX was tested for each subject.The threshold of uNTX was chosen as 65 nmol bone collagen equivalents (BCE)/mmol creatinine (Cr) for the diagnosis of bone metastasis.Patients with uNTX greater than 65 nmol BCE/mmol Cr would be diagnosed as having bone metastasis.Other examinations (CT,MRI,PET/CT or bone biopsy) were also performed to confirm the diagnosis.The uNTX values of benign and malignant bone lesions were compared using two-sample t test.The diagnostic efficacy of uNTX combined with BS was evaluated.A ROC curve was analyzed to evaluate the cut-off value of uNTX for the diagnosis of bone metastasis.Results The mean value of uNTX of all 227 patients was (84.30± 13.29) nmol BCE/mmol Cr,which was significantly higher than the upper limit of normal range (t =21.875,P＜0.01).Using 65 nmol BCE/mmol Cr as the threshold,197 cases were diagnosed as with and 30 without bone metastases,in which 188 and 27 were respectively confirmed by other examinations.The mean uNTX was (88.73 ± 8.37) and (60.76± 9.14) nmol BCE/mmol Cr in patients with and without bone metastases,respectively (t =-18.134,P＜0.01).The sensitivity,specificity,positive predictive value,negative predictive value,accuracy and Youden index of uNTX combined with BS were 98.4％ (188/191),75.0％ (27/36),95.4％ (188/197),90.0％ (27/30),94.7％ (215/227) and 73.4％ respectively.The cut-off value by ROC curve analysis was 78.88 nmol BCE/mmol Cr and the area under the curve was 0.982.Using 78.88 nmol BCE/mmol Cr as threshold,the corresponding sensitivity,specificity,positive predictive value,negative predictive value,accuracy and Youden index were 97.4％(186/191),94.4％(34/36),98.9％(186/188),87.2％(34/39),96.9％(22/227) and 91.8％ respectively.Conclusions Using the cut-off value of 78.88 nmol BCE/mmol Cr,uNTX may have clinical value in helping the differential diagnosis of bone scintigraphy for patients suspected of metastatic bone disease.
ABSTRACT
10.3969/j.issn.1000-8179.2013.12.002