Bone health in long-term survivors of acute lymphoblastic leukemia in
children and ado-lecents. 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 persist 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, 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 – Similarities of average
values in multiple metrics with those in healthy subjects obscured
deficits in both trabecular and cortical bone, as well as bone strength,
revealed by 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 somehat 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.