[Accretion of bone mass in patients treated for childhood acute lymphoblastic leukemia]

Abstract

Chemotherapeutic agents such as glucocorticoids, methotrexate, antymetabolities, cranial and local irradiation) may severely disturb normal growth, bone mineral acquisition and skeletal development because the most individuals go through the stages of rapid growth when childhood acute lymphoblastic leukemia (ALL) is diagnosed.

Aim of the study: Analysis of the bone density accretion in children and adolescents in various time after tretament for acute lymphoblastic leukemia.

Materials and methods: We examined 107 patients (70 males) who had been treated for ALL according to the protocol of the Polish Pediatric Leukemia, Lymphoma Study Group. Mean age at diagnosis was 7.3 years (range 1-19 years). They received chemotherapy with different doses of methotrexate: 46 patients - 5 g/m2; 24 - 2 g/m2 and 37 children received in doses of 0,5-1 g/m2. Cranial irradiation was performed in 22 patients in doses of 12 Gy, in 39 patients in doses of 18 Gy, 46 children did not receive cranial irradiation. The examinations were performed three times. First: immediately after end of maintenance therapy; second: 1,5 years after therapy and third: longer than 5 years after therapy. History of fractures, bone mineral density (BMD) measurements of lumbar spine (L2-L4) and total body were performed using dual-energy x-ray absorptiometry (GE Medical Systems Lunar DPX-L), expressed as g/cm2 and compared to reference values obtained from the 473 age - and gender-matched healthy children from the same region of Poland.

Results: at all points we did not find any differences between studied group and age- and gender-matched peers: BMI Z-score 0.77 vs 1.57 vs 0.72); BMD-total Z-score (-0.11 vs 0.012 vs 0.21); BMD-spine Z-score (0.03 vs 0.10 vs 0.08). BMD SDS > - 2 in first study was observed in 11.5% patients, in second - in 10% and in last - in 7.1% patients. In consecutive examinations we observed accretion of bone mass, similar as in healthy populationi. Age at diagnosis, gender, cumulative doses of steroids, using CNS radtiotherapy, high doses of methotrexate did not relate to examined (after treatment) parameters. Patients with history of fractures had lower BMD-total in second assessment and lower BMD-spine in all examiantions, however, statistical significant was not reach.

Conclusions: The disease itself and its complex treatment did not disturb the bone density accretion in examined patients. The patients with history of fractures (before and after tretament) tended to have lower mean values of bone density, (especially in region of spine) than patients without fractures. Small number of patients in last examination did not allowed to conclude about peak bone mass in our patients.