[Efficacy and safety of letrozole in treatment of McCune-Albright syndrome girls with peripheral precocious puberty].

OBJECTIVE: To evaluate the efficacy and safety of the third-generation aromatase inhibitor letrozole in the treatment of McCune-Albright syndrome (MAS) girls with peripheral precocious puberty.

METHODS: Twenty-one MAS girls with peripheral precocious puberty treated in Pediatrics Department of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from March 2012 to June 2017 were enrolled in the study. Patients presented with repeated vaginal bleeding, premature breast enlargement, café-au-lait spots or dysplasia of bone fibers, and low levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH); and the congenital adrenal hyperplasia, estrogen-producing tumors, and exogenous estrogen intake were excluded. Letrozole were administrated at a dose of 0.5-2 mg·m -2 ·d -1 for 6 to 12 months. The patients were observed for changes in breast staging, vaginal bleeding, sex hormone levels, liver function and bone age changes, and changes in uterine and ovarian volume.

RESULTS: After treatment, bone age/chronological age (BA/CA)was decreased from 1.23±0.30 to 1.11±0.18 ( P < 0.01); the predicted adult height (PAH) increased from (156.2±5.9)cm to (158.4±2.1)cm after treatment ( P < 0.05); the vaginal bleeding was reduced and the estradiol level decreased, while the teststosterone level and the uterus showed no significant increase, and no adverse reactions such as ovarian torsion and abnormal liver function were observed.

CONCLUSIONS: Precocious puberty is one of the most common endocrine manifestations in MAS. Our findings suggest that letrozole may be an effective and safe therapy to precocious puberty in girls with McCune-Albright Syndrome.