Sequential analysis of biochemical markers of bone resorption and bone densitometry in multiple myeloma

Bone lesions often occur in multiple myeloma (MM), but no tests have proven useful in identifying patients with increased risk. Bone marker assays and bone densitometry are non-invasive methods that can be used repeatedly at low cost. This study was performed to evaluate these methods in predicting bone events in MM patients.

Thirty newly diagnosed MM patients were enrolled. Serum C-terminal telopeptide (ICTP) and urinary N-terminal telopeptide (NTx) of collagen I were measured for assessment of bone resorption, and serum C-terminal (PICP) and N-terminal (PINP) propeptides of procollagen I, bone-specific alkaline phosphatase, and osteocalcin were measured to estimate bone formation. Dual energy X-ray absorptiometry (DEXA) was used to assess bone mineral density (BMD) of the lumbar spine, hip, and whole body. Serum and urine samples were collected every 6 weeks, DEXA-scans performed every 3 months, and skeletal radiographs were done every 6 months as well as when indicated.

Serum ICTP and urinary NTx were predictive of progressive bone events. Markers of bone formation, bone mineral density assessments, and M component measurements were less informative. In Cox analysis, ICTP showed the highest predictive value, but should be replaced with NTx in patients with nephropathy. Pretreatment low lumbar BMD was predictive of early vertebral fractures.

Sequential DEXA-scans showed heterogeneous local BMD changes, and our data do not support routine use of sequential DEXA-scans. However, lumbar DEXA-scans at diagnosis can identify patients with increased risk of early vertebral collapses. Sequential analyses of serum ICTP and urinary NTx are useful for monitoring bone damage.