title: Early decrements in bone density after completion of neoadjuvant chemotherapy in pediatric bone sarcoma patients.
abstract: BACKGROUND
  Bone mineral density (BMD) accrual during childhood and adolescence is important for attaining peak bone mass. BMD decrements have been reported in survivors of childhood bone sarcomas. However, little is known about the onset and development of bone loss during cancer treatment. The objective of this cross-sectional study was to evaluate BMD in newly diagnosed Ewing's and osteosarcoma patients by means of dual-energy x-ray absorptiometry (DXA) after completion of neoadjuvant chemotherapy.
  
  
  METHODS
  DXA measurements of the lumbar spine (L2-4), both femora and calcanei were performed perioperatively in 46 children and adolescents (mean age: 14.3 years, range: 8.6-21.5 years). Mean Z-scores, areal BMD (g/cm2), calculated volumetric BMD (g/cm3) and bone mineral content (BMC, g) were determined.
  
  
  RESULTS
  Lumbar spine mean Z-score was -0.14 (95% CI: -0.46 to 0.18), areal BMD was 1.016 g/cm2 (95% CI: 0.950 to 1.082) and volumetric BMD was 0.330 g/cm3 (95% CI: 0.314 to 0.347) which is comparable to healthy peers. For patients with a lower extremity tumor (n = 36), the difference between the affected and non-affected femoral neck was 12.1% (95% CI: -16.3 to -7.9) in areal BMD. The reduction of BMD was more pronounced in the calcaneus with a difference between the affected and contralateral side of 21.7% (95% CI: -29.3 to -14.0) for areal BMD. Furthermore, significant correlations for femoral and calcaneal DXA measurements were found with Spearman-rho coefficients ranging from ρ = 0.55 to ρ = 0.80.
  
  
  CONCLUSIONS
  The tumor disease located in the lower extremity in combination with offloading recommendations induced diminished BMD values, indicating local osteopenia conditions. However, the results revealed no significant decrements of lumbar spine BMD in pediatric sarcoma patients after completion of neoadjuvant chemotherapy. Nevertheless, it has to be taken into account that bone tumor patients may experience BMD decrements or secondary osteoporosis in later life. Furthermore, the peripheral assessment of BMD in the calcaneus via DXA is a feasible approach to quantify bone loss in the lower extremity in bone sarcoma patients and may serve as an alternative procedure, when the established assessment of femoral BMD is not practicable due to endoprosthetic replacements.
authors.affiliation: Motion Analysis Lab, Department of General Orthopedics and Tumororthopedics, University Hospital Münster, Domagkstr, 3, 48149 Münster, Germany. c.mueller@uni-muenster.de
authors.forename: Carsten
authors.initials: C
authors.lastname: Müller
authors.forename: Corinna C
authors.initials: CC
authors.lastname: Winter
authors.forename: Dieter
authors.initials: D
authors.lastname: Rosenbaum
authors.forename: Joachim
authors.initials: J
authors.lastname: Boos
authors.forename: Georg
authors.initials: G
authors.lastname: Gosheger
authors.forename: Jendrik
authors.initials: J
authors.lastname: Hardes
authors.forename: Volker
authors.initials: V
authors.lastname: Vieth
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D015519:Bone Density / Q000502:physiology*; D001859:Bone Neoplasms / Q000188:drug therapy / Q000503:physiopathology*; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D002648:Child; D003430:Cross-Sectional Studies; D005240:Feasibility Studies; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008297:Male; D020360:Neoadjuvant Therapy / Q000009:adverse effects; D012516:Osteosarcoma / Q000188:drug therapy / Q000503:physiopathology*; D012307:Risk Factors; D012512:Sarcoma, Ewing / Q000188:drug therapy / Q000503:physiopathology*; D055815:Young Adult