EVOLUTION OF BONE DENSITOMETRY IN PATIENTS WITH MYELOMA TREATED WITH CONVENTIONAL OR INTENSIVE THERAPY

Background. Demineralization is a common hallmark of multiple myeloma (MM) that can be evaluated by dual-energy X-ray absorptiometry (DEXA). The evolution of lumbar and whole body bone density were investigated by DEXA in patients with MM treated by conventional or intensive ther apy supported by autologous blood stem cell transplantation. Methods. Sixty six patients younger than 66 years with MM were randomly assigne d to either conventional (30 patients, Group A) or intensive therapy s upported by autologous blood stem cell transplantation (36 patients, G roup B). For all patients, lumbar bone mineral density (BMD) was measu red by DEXA at diagnosis and 13.2 +/- 4.2 months after the initiation of treatment. Whole body examinations were performed in 45 patients; i n addition to whole body BMD, independent BMD values were recorded for various skeletal sites. Results. At diagnosis, mean lumbar Z score (l umbar mean BMD value) was low (-1.24 +/- 1.45) without any significant difference between the 2 groups. Under treatment, lumbar BMD increase d 0.7% in Group A and 4.6% in Group B (P = 0.02). This difference was mainly related to nonresponders in group A who featured a lumbar BMD c hange of -3.9%, whereas patients in remission in both groups displayed a 4.1% increase (P < 0.001). There was a correlation between the vari ation of lumbar BMD and the decrease of the serum or urinary monoclona l component (r = 0.34, P = 0.006). After intensive therapy, increase o f lumbar BMD was higher in men than in women (7.2% vs. 1%, P = 0.005) perhaps because of variations in hormonal status in women. Unexpectedl y, whole body BMD decreased in responders (-3%) because of a decrease in appendicular BMD outweighing the increase in axial BMD. in patients with MM responsive to chemotherapy. Conclusion. Bone densitometry is a marker of treatment response that may be particularly useful in nons ecretory and light chain MM. Moreover, it provides new information on bone remodeling in patients treated for MM, which may have therapeutic consequences.