Stereotactic radiosurgery — a targeted form of radiation therapy — can effectively reduce hormone levels and control tumor progression in children and adolescents with hormone-secreting pituitary adenomas, particularly those with Cushing’s disease and acromegaly, a retrospective study shows.
The study, “Outcomes after Gamma knife Stereotactic Radiosurgery in pediatric patients with Cushing’s disease or Acromegaly: A multi-institutional study,” was published in the journal World Neurosurgery.
In children and adolescents, tumors of the pituitary gland are rare, comprising less than 3% of all brain tumors. Most of these tumors are functioning adenomas — benign tumors that produce excess pituitary hormones, including the adrenocorticotropic hormone (ACTH), the cause of Cushing’s disease — and growth hormone, the cause of acromegaly.
While functioning adenomas can be treated with surgery, radiation therapy, medical treatment, and stereotactic radiosurgery, little is known about the effectiveness of this last approach in pediatric patients.
Stereotactic radiosurgery, also known as gamma knife surgery, is a non-invasive procedure that targets a very small area and delivers much higher doses of radiation, in fewer treatments, than traditional radiation therapy. It often is used to eliminate small brain and pituitary gland tumors.
An international team led by researchers at the University of Virginia reviewed data from 36 pediatric patients — age 10 to 21 for a median of 18 years — who received stereotactic radiosurgery for their Cushing’s disease (24 patients) or acromegaly (12 patients) between 1990 and 2016.
After a median follow-up of four years and four months, 70.8% of those with Cushing’s had their ACTH levels return to normal, meaning they achieved endocrine remission. However, four of these patients experienced disease recurrence up to 16 months after remission.
In the acromegaly group, five patients achieved normal levels of the IGF-1 signaling protein. These levels increased again in four patients, but all were successfully treated with additional medical therapy.
Overall, younger patients (less than 15 years) and those who had received a higher margin dose were more likely to achieve remission.
Stereotactic radiosurgery also controlled tumors in 87.5% of Cushing’s patients and in 92% of those with acromegaly. Among these, 53% and 83%, respectively, experienced a reduction in tumor volume by 30% or more.
The most common adverse reaction in both groups was pituitary hormone deficiency, which was reported in five patients with Cushing’s and two with acromegaly.
In general, “the Cushing’s disease group fared better than the patients with acromegaly,” researchers wrote.
Supported by these findings, the team believes “stereotactic radiosurgery is better than medication alone and carries a low risk of hormonal and neurological dysfunction. And, as such, reduces the burden of lifelong medications and their associated side effects in pediatric patients.”
Additional studies are still warranted to explore the long-term outcomes of this therapeutic strategy, they advised.