Dual-energy X-ray absorptiometry and biochemical markers of bone turnover after autologous stem cell transplantation in myeloma.

Objectives: To evaluate the effect of high-dose chemotherapy (HDT) followed by autologous stem cell transplantation (ASCT) on bone turnover and bone mineral density in a cohort of 39 consecutive patients with multiple myeloma (MM).

Methods: Phosphorus and calcium parameters, bone turnover markers, and bone mineral density were studied. Timepoints were diagnosis (T1), just before ASCT (T2), 6 months (T3) after ASCT, and 1 yr (T4) after ASCT.

Results: No bone mineral loss was shown on dual-energy X-ray absorptiometry (DXA) at T1 (lumbar Z-score -0.02, femoral neck Z-score 0.77) or during follow-up. Chronic vitamin D deficiency (25OHD3 11.7 ± 7.7 ng/mL at T1) and relative hyperparathyroidism from T2 to T4 were observed. In spite of this moderate hyperparathyroidism, serum C-telopeptide of type I collagen (CTX) decreased significantly between T1 and T4. Bone alkaline phosphatase levels were low at diagnosis and showed no significant change after ASCT, unlike DKK1 levels that were high at diagnosis and decreased 6 months after ASCT in patients not previously treated with bisphosphonates.

Conclusion: Bone demineralization is moderate in multiple myeloma. ASCT induces a decrease in bone resorption but no changes in bone formation, remaining low despite the decrease in DKK1. Bone mineral loss, evaluated by DXA, is moderate in multiple myeloma. High-dose chemotherapy followed by ASCT leads to decreased bone resorption but osteoblastic bone formation remains low, in spite of reduced circulating DKK1.