Patients diagnosed with a brain tumor affecting the body’s “master gland” have encouraging news: When the tumor is removed using minimally invasive surgery, patients can enjoy a good chance of restoring normal hormonal function and recovering their health.

A landmark study published in the October 2008 issue of Neurosurgery, reported on 444 patients undergoing surgery to remove a tumor of the pituitary gland, called a pituitary adenoma, all of whom were operated on by the same neurosurgeon, Daniel F. Kelly, M.D., Director of the Brain Tumor Center at Saint John’s Health Center.

Dr. Kelly, the senior author of the study, specializes in endonasal transsphenoidal surgery, a minimally invasive procedure that allows doctors to reach the pituitary tumors and brain tumors directly through a nostril without incisions on the face. The surgery is performed with an operating microscope which provides brilliant light and magnification, and frequently with an endoscope, a thin, lighted tube directly inserted into the nostril, that provides a more panoramic view than the microscope. Miniaturized surgical instruments are inserted via a nostril, passing through the butterfly-shaped sphenoid bone at the base of the skull to reach the tumor. In recent years, this high-tech approach has replaced a more traditional and more painful approach under the lip called sublabial transsphenoidal surgery.

The new study found that only 5% of Dr. Kelly’s patients lost pituitary hormonal function after the tumor mass was removed by endonasal surgery, while 50% showed improvement in hormonal function. The most favorable outcomes involved cases when tumors were relatively small, and in patients who were younger in age and did not suffer from hypertension. The highest rate of new pituitary gland damage (14%) occurred in the largest tumors measuring over 3 cm in size.

While the pituitary is very small, about the size of a pea (1 cm), this “master gland” secretes powerful hormones that help coordinate and control such basic functions as growth and development, metabolism, the stress response, sexual function, libido and water balance. Although pituitary adenomas are rarely malignant, they can trigger serious health problems if they damage the gland’s ability to secrete hormones, grow large and compress the optic nerves leading to loss of vision or cause headaches. If hormonal loss does occur as a result of a pituitary tumor or surgical removal of a tumor, hormone replacement such as thyroid, testosterone or estrogen therapy may be prescribed by an endocrinologist.