ESPE Abstracts

Background: Childhood cancer survivors (CCS) are at risk for low bone mineral density (BMD).

Objective: Aim of our study was to evaluate the prevalence of low BMD and it’s determinants in a single-center cohort of CCS.

Method: One-hundred-eighty-five CCS (103M, 84F) diagnosed with liquid-LT-(n=48), solid-ST-(n=88) and brain tumor-BT-(n=51) at the age of 5.3±3.2 years underwent height, BMI (SDS), Tanner staging and DXA scan for total body-TB and spine-L1-L4 BMD (gr/cm², Z-score), BMC (gr) and for TB fat mass(FM, kg) and free fat mass (FFM, kg). Endocrine defects were found in n=9LT, n=16ST and n=50BT; 48/51BT underwent CRT(mean total dose 5397.5±1426.1 cGy).

Results: Patients were evaluated 6.8±3.3 years after off therapy at the age of 13.0±2.0 years. LT were significantly younger than BT (12.9±1.8 vs 13.7±1.7 years) and BT shorter than ST (−0.60±1.26 vs 0.24±1.37 SDS, P<0.001); the 3 categories did not differ for Tanner stage nor for BMI SDS (range 1.34-LT to 1.57-BT). BT presented a lower TBBMD (−0.61±0.89) and L1-L4BMD Z-scores (−0.74±1.14) compared to ST and LT (P’s<0,01). A TBBMD Z-score <−2 and between −2 and −1 was found in 4.8% (7.8%-BT, 6.5%-LT and 2.2%-ST) and 14% (23.5%-BT, 6.2%-LT and 12.6%-ST) of CCS, respectively; a L1-L4BMD Z-score <−2 and between −2 and −1 in 7% (13.7%-BT, 6.5%-LT and 3.4%-ST) and 15.6% (19.6%-BT, 16.7%-LT and 12.6%-ST), respectively. TBBMD Z-score was directly associated to FFM (r’s=0.51) and inversely to RT dose in BT (r=−0.30, P=0.037); hormone defects were inversely related to L1-L4 and TBBMD Z-scores in LT and ST, but not in BT. Multiple regression analyses showed that L1-L4BMD Z-score was independently and inversely predicted by age and hormone defects and directly by FFM and FM after correction for Tanner stage and height SDS (R² 0.33, P<0.0001), while TBBMD Z-score by all the previous parameters, except for Tanner stage (R² 0.50, P<0.0001).

Conclusion: Up to 14% of BTCCS and 6.5% of LTCCS present a low bone mass at the age of 13 years. Older age, hormone defects and CRT are negative predictors of low BMD.