Young age at diagnosis, male sex, and decreased lean mass are risk factors of osteoporosis in long-term survivors of osteosarcoma.

BACKGROUND: Long-term survival of children with osteosarcoma has increased, but most suffer from osteoporosis in adulthood. The aim of this study was to investigate the prevalence and identify the risk factors of osteoporosis.
METHODS: Forty long-term survivors of osteosarcoma and 55 controls were enrolled. The mean age of the survivors was 21.8 ± 5.2 years. They were diagnosed at younger than 23 years of age (mean, 14.9 + 5.0 y). Bone mineral densities (BMD) and body compositions were measured by dual-energy x-ray absorptiometry.
RESULTS: Nineteen (47.5%) subjects had osteoporosis and 12 (30.0%) had osteopenia. The regions affected by osteoporosis were: femur neck of osteosarcoma site (47.5%), unaffected femur neck (12.5%), lumbar spine (12.5%), and total body (15.0%). Twelve subjects (30.0%) had 14 episodes of fractures. The identified risk factors of osteoporosis were young age at diagnosis, male sex, and low lean mass. Subjects diagnosed before attainment of puberty (male ≤ 16 y, female ≤ 14 y) were found to have a higher prevalence of osteoporosis (37.5% vs. 10.0%, P < 0.01). Males had a higher prevalence of osteopenia or osteoporosis than females (86.4% vs. 66.7%, P < 0.01). Total lean mass was positively correlated with unaffected femur neck BMD. Regional lean mass in affected limb was significantly reduced along with affected femur neck BMD.
CONCLUSIONS: In long-term survivors of osteosarcoma, prevalence of osteoporosis and fracture was higher than expected. Initial evaluation and regular follow-up of BMD should be performed in all osteosarcoma patients, especially in those who did not attain puberty, males, and those with a low lean mass.