Clinical Significance Of Urinary N-telopeptide Of Type Ⅰ Collagen On Treatment Of Bone Abnormalities In Multiple Myeloma

BackgroundMultiple myeloma (MM) is a neoplastic plasma-cell disorder characterized by osteolytic bone disease resulting in skeletal-related events (SRE), which not only result in anegative impact on patients’ quality of life, but also increase economic burden. About2/3of the patients experience severe pain, and80%of them show skeletal abnormalities in x-ray, including pathologic fractures, diffuse osteoporosis and osteolyses. Many patients had been treated with bisphosphonate during chemotherapy. Now, diagnosis and monitoring of bone disease mainly depend on imaging, but low sensitivity of the x-ray, and high expenses of Positron emission tomography-computed tomography (PET-CT), Magnetic resonance imaging (MRI), CT limited their use. The clinical detections of serum alkaline phosphatase (AKP) reflecting serum osteoblast activity and calcium concentration reflecting the balance between mineralization and bone resorption are convenient, but not specific. New laboratory parameters that reflect bone metabolism accurately are urgently needed. In recent years, it has been found that type I collgen cross-linked N-telopeptide (NTx) plays an important role for bone lesion detection in many diseases but seldom reported in MM. MethodsIn this study, patients with MM were diagnosed between2009and december2010including64patients with multiple myeloma received bisphosphonate and chemotherapy to treat bone pain. We detected the level of urinary NTx/Cr of the64patients by ELIS A techniques before and after three months of treatment, as well as-(AKP), serum calcium, GLB, β2-MG, Cr, Hb.Results(1) The urinary NTx/Cr of patients in D-S stage Ⅲ was higher than that of patients in stage I, II;the level of urinary NTx/Cr decreased significantly after chemotherapy,there was statistical significance; and with the prolonged the period, urinary NTx/Cr decreased; and the patients of mild reaction or no reaction after treatment had higher levels of urine NTx/Cr. At the same time, we also found that more serious bone lesions in X-ray the higher urinary NTx/Cr levels, and the heavier bone pain symptoms the higher urinary NTx/Cr levels.(2) Comparative analysis of urinary NTx/Cr and other indicators:the level of urinary NTx/Cr and serum β2-MG was positively correlation (P=0.013, r=0.308) before treatment; also positively correlation with LDH (P=0.043, r=0.254). Before and after the treatment, the variation of urinary NTx/Cr and serum β2-MG was positively correlation (P=0.043, r=0.253); and also positively correlation with LDH variation (P=0.045, r=0.354).ConclusionThe urinary NTx/Cr is a sensitive and specific parameter for bone resorption which indicates efficacy affter chemotherapy and bisphosphonate treatment on bone abnormalities. It can also identify tumor load and its prognosis. Besides, its concentration is correlated with the activity of the tumor. Urinary NTx/Cr as one of bone metabolism markers is highly associated with bone destruction of MM. Monitoring urinary NTx/Cr can reflect progression and treatment efficacy of MM.