Are aromatase inhibitors in boys with predicted short stature and/or rapidly advancing bone age effective and safe?

Abstract

Background: The aim of this study was to assess aromatase inhibitor (AI) efficacy in increasing predicted adult height (PAH) and to describe clinical and biochemical safety profiles of AI-treated boys. Methods: A retrospective chart review was conducted at an academic children's hospital endocrinology clinic. Twenty-one boys with predicted short stature and/or rapidly advancing bone age, divided as Tanner stage (TS) I-III Group 1 (G1, n = 9) and TS IV-V Group 2 (G2, n = 12), were treated with AIs, either letrozole or anastrozole (mean duration, G1: 2.4 years and G2: 0.9 years). Primary outcomes included PAH, hormonal/biochemical analytes, and clinical data. Results: PAH did not significantly change in either group. Mean peak testosterone significantly increased from baseline to 650 ± 458 ng/dL (p = 0.008) in G1 and to 1156 ± 302 ng/dL (p = 0.002) in G2. Estradiol did not significantly change in either group. Compared to baseline, G2 showed increased mean FSH (p = 0.002), LH (p = 0.002), hematocrit (p = 0.0001), body mass index (BMI) z-score (p = 0.0005), and acne (p = 0.01). Conclusions: AIs did not increase PAH, regardless of TS. Boys in late puberty had significant increases in testosterone, gonadotropins, hematocrit, acne, and BMI, but no reduction in estradiol. The potential consequences of these findings are concerning and require long-term study, especially if AIs are started in late puberty.