Original Article

J Korean Soc Pediatr Endocrinol. 2006; 11(1): 40-44.

Effect of Potent Aromatase Inhibitor (Letrozole) on Bone Maturation and Predicted Adult Height in Boys with Early Puberty.

Ji Yong Kim, Eun Young Cha, Min Ho Jung, and Byung Churl Lee

Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea. byungcl@catholic.ac.kr

PURPOSE
We evaluated the effect of potent aromatase inhibitor (Letrozole) on the rate of bone maturation and an increase in predicted adult height (PAH) in boys with early puberty. METHODS: Nine boys, aged 10.9-12.9 years, with early puberty were studied. The boys were treated with the aromatase inhibitor, letrozole, 2.5 mg/day for 1 year. The main outcome parameters were the change in bone age and predicted adult height. Also, serum LH, FSH, testosterone and estradiol concentrations were measured and sexual maturation before and after 12 months of treatment were evaluated.
RESULTS
PAH significantly increased by 3.3 cm (P<0.05) and PAH standard deviation score significantly increased by 0.6 (P<0.05). Bone age before therapy advanced by 0.72+/-0.93 year, but bone age after therapy decreased by 0.07+/-0.90 year compared to chronological age (P<0.01). Whereas, sexual maturation of the subjects progressed normally.
CONCLUSION
These results suggest that treatment with the potent aromatase inhibitor, letrozole, delays bone maturation and improves PAH in boys with early puberty.

Keywords : Aromatase inhibitor, Early puberty, Predicted adult height, Bone maturation