Fractionated Stereotactic Radiation More Effective Than Single-Dose Radiation in Pituitary Tumors
A recent study at Houston Methodist Hospital proved that multiple small doses of highly focused radiation therapy is safer and more effective than a single larger dose of radiation at destroying pituitary gland tumors. The findings on the use of fractionated stereotactic radiotherapy were published by Barber et al in Neurosurgery.
The pituitary gland is known as the “master gland” because the hormones it secretes control the functions of many endocrine glands (such as the thyroid and the adrenals). While pituitary adenomas are slow-growing and usually benign, their growth can cause the pituitary gland to produce excess hormones or block hormone production altogether. This can disrupt the regulation of critical body functions such as heart function, blood pressure, glucose regulation, fertility, sexual function, and metabolism.
“Even using pinpoint techniques, a single dose of radiation may not be enough to kill the residual tumor,” said David S. Baskin, MD, Vice Chair of the Department of Neurosurgery and Director of the Kenneth R. Peak Brain and Pituitary Tumor Center at Houston Methodist Hospital. “Our radiation oncologists strategized on using fractionated stereotactic radiotherapy as the best way to kill these slow growing masses.”
Fractionated stereotactic radiotherapy is a treatment given in multiple small doses over a period of time. Considered a variation of the traditional stereotactic radiosurgery, fractionated stereotactic radiotherapy can treat the pituitary adenomas more aggressively than a single dose and with fewer complications than stereotactic radiosurgery.
Study Findings
The Houston Methodist study not only supported this, Dr. Baskin said, but demonstrated that fractionated stereotactic radiotherapy was actually more effective in the long term than both stereotactic radiosurgery and conventional radiotherapy.
“We treated and followed 75 patients who underwent [fractionated stereotactic radiotherapy] for a residual pituitary adenoma between 2004 and 2013,” said Bin Teh, MD, Vice Chair of Houston Methodist's Department of Radiation Oncology. “None of them experienced any tumor recurrence during our monitoring period, and nearly 70% of those with hormonal imbalances caused by the adenomas returned to normal levels.”
Further studies will investigate the long-term (10 years or greater) safety and efficacy of fractionated stereotactic radiotherapy in larger groups of patients.
“We also plan to conduct prospective research that will evaluate [fractionated stereotactic radiotherapy] and [stereotactic radiosurgery] so that the benefits and limitations of both therapies in treating pituitary adenomas can be directly compared,” said Dr. Baskin.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
