Bone health in long‐term survivors of pediatric acute lymphoblastic leukemia. An assessment by peripheral quantitative computed tomography

Abstract

Background: Loss of bone mineral is a common concomitant of the treatment of acute lymphoblastic leukemia (ALL) due mainly to chemotherapy, especially with corticosteroids. Osteopenia/osteoporosis may be encountered long into survivorship. Measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry is limited to two-dimensionality and cannot distinguish trabecular from cortical bone.Methods: A sample of 74 subjects, ages 13.5-38.3 years more than 10 years from diagnosis, underwent peripheral quantitative computed tomography (pQCT) at metaphyseal (trabecular bone) and diaphyseal (cortical bone) sites in the radius and tibia. pQCT provides three-dimensional assessment of bone geometry, density, and architecture.Results: Average values in multiple metrics were similar to those in healthy individuals, but deficits in both trabecular and cortical bones were revealed by lower Z scores using an ethnically comparable sample of healthy individuals. Connectivity, a measure of bone architecture and a surrogate measure of bone strength, was lower in females than males. Survivors of standard-risk ALL had greater connectivity in and more compact trabecular bone than high-risk survivors who had received more intensive osteotoxic chemotherapy. There were no statistically significant differences in any of the metrics at any of the sites between subjects who had or had not a history of fracture, cranial irradiation, or use of a bisphosphonate.Conclusions: These long-term survivors of ALL have somewhat compromised bone health, but data in comparable healthy populations are limited. Longitudinal studies in larger and more ethnically diverse cohorts will provide greater insight into bone health in this vulnerable population.

The Influence of Body Composition on Bone Health in Long-term Survivors of Acute Lymphoblastic Leukemia in Childhood and Adolescence: Analyses by Dual-energy Radiograph Absorptiometry and Peripheral Quantitative Computed Tomography

“…In addition, the age-related rate of decline in these metrics of trabecular bone health was greater in women than in men 43. These sex differences are all evident in our cross-sectional study of long-term survivors of ALL 8…”

“…43 These sex differences are all evident in our cross-sectional study of long-term survivors of ALL. 8 We were still left with no explanation for the lack of association of ALMI with any of the metrics of trabecular bone health. This prompted us to adopt the approach used in our previous studies of body composition in this population based on ALMI Z scores.…”

“…Measures of these elements of body composition are provided most commonly by dual-energy radiograph absorptiometry (DXA), for this instrumentation is widely available in high-income countries and has contributed to large studies of the general population 7. Much less available is the technology of peripheral quantitative computer tomography (pQCT) which provides detailed separate measurement of trabecular and cortical bone, not possible with DXA 8. In addition, pQCT enables the assessment of bone geometry, architecture and mineralization which can provide estimates of bone strength 8.…”

“…7 Much less available is the technology of peripheral quantitative computer tomography (pQCT) which provides detailed separate measurement of trabecular and cortical bone, not possible with DXA. 8 In addition, pQCT enables the assessment of bone geometry, architecture and mineralization which can provide estimates of bone strength. 8 Accordingly, this study was performed to take advantage of the complementary merits of DXA and pQCT in an exploration of the interrelationships of body composition and bone health in long-term survivors of ALL in childhood and adolescence.…”

“…8 In addition, pQCT enables the assessment of bone geometry, architecture and mineralization which can provide estimates of bone strength. 8 Accordingly, this study was performed to take advantage of the complementary merits of DXA and pQCT in an exploration of the interrelationships of body composition and bone health in long-term survivors of ALL in childhood and adolescence. The objective was to determine the associations of measures of body composition obtained by DXA, exemplified by sarcopenic obesity, with measures of bone health obtained by pQCT.…”