Management of prolactinomas in children and adolescents; which factors define the response to treatment?

PURPOSE: Prevalence, presentation and clinical outcome of prolactinomas vary in children and adults. In this study, we evaluated the clinical features and outcome of children and adolescents with prolactinoma to identify the differences from that of adults, and thus to establish the management strategies for this age group.
METHODS: Patients with prolactinoma diagnosed before 18 years of age from a single center in the last 20-years were included. Clinical and laboratory data, radiological findings and treatment outcome were evaluated retrospectively.
RESULTS: Twenty-eight patients (23 female; 82.1%) with prolactinoma were included. Median age at diagnosis was 15.2 years (12.6-17.7 years) in girls, 12.9 years (12.0-16.7 years) in boys. First line treatment was cabergoline in 82% of patients and normal prolactin level was achieved with maximum dose of 2 mg/week in 78%. Surgery was required in 28% of patients. Adenomas < 13.5 mm responded conventional doses of CAB. Adenomas > 30 mm were drug resistant or required surgery. Adenomas between 13.5 mm and 30 mm with invasion/extension were more likely to have drug resistance. CAB had to be continued following surgery in all patients. One macroprolactinoma had an increase in size which was accompanied with increasing prolactin level.
CONCLUSIONS: All microprolactinomas responded well to DA treatment. However, all adenomas larger than 30 mm was resistant to CAB or required surgery. Probability of drug resistance and requirement of second line therapy were higher in adenomas between 13.5 mm and 30 mm with invasion/extension. Doses over 2 mg/week of CAB in drug-resistant patients may not provide additional benefit. The frequency of follow-up MRI could be determined based on prolactin levels and emergence of new neurological symptoms.