Tamoxifen treatment for precocious puberty in McCune-Albright syndrome: a multicenter trial

OBJECTIVE: We undertook a 1-year multicenter trial of tamoxifen treatment for precocious puberty in girls with McCune-Albright syndrome (MAS). STUDY DESIGN: Girls < or =10 years with classic or atypical MAS were recruited. Pretreatment history was collected for 6 months. Patients received 20 mg tamoxifen daily. Diaries were used to record bleeding. Evaluations included physical examination, bone age, pelvic ultrasound, hormone levels, and safety assessments. RESULTS: A total of 28 girls (2.9-10.9 years of age) were enrolled from 20 centers, of whom 25 completed 12 months of tamoxifen treatment. Compared with before the study, vaginal bleeding episodes decreased (3.42+/-3.36/year vs 1.17+/-1.41/year), growth velocity slowed (SDS 1.22+/-2.65 vs -0.59+/-3.06, P=.005), and rate of bone maturation decreased (1.21+/-0.78 vs 0.72+/-0.36, P=.02). Ovarian volumes were enlarged and asymmetric throughout the study, and uterine volumes were increased. No adverse events occurred. CONCLUSIONS: Tamoxifen treatment of precocious puberty in MAS results in a reduction of vaginal bleeding and significant improvements in growth velocity and rate of skeletal maturation.