Success of surgery depends on the size and location of the tumor, and the experience and skills of the neurosurgeon. For example, surgery is more successful with a tumor smaller than 10-millimeters compared with a tumor greater than 10-millimeters in size. In our experience, more than 90% of patients have normal GH and IGF-1 hormone levels following surgery. The expertise of the surgical team is a key factor in achieving best possible results with very low complication rates. Recent surgical innovations introduced by Dr. Fernandez-Miranda, such has removal of the medial wall of the cavernous sinus and removal of cavernous sinus tumors, have significantly improved surgical outcomes in acromegalic patients.

Surgery for acromegaly is a delicate procedure, which should be performed by highly specialized surgeons at multidisciplinary Pituitary centers. In the past, the most common operation was an approach called microscopic transsphenoidal surgery. At Stanford, our neurosurgeons and rhinologists use a more advanced endoscopic endonasal approach to access the pituitary gland through the nostrils. Our operating rooms are equipped with 4K endoscopic visualization technology and very fine instruments.

Medication or radiation therapy may be recommended after surgery to help normalize levels of growth hormone. At Stanford, less than 10% of patients require medical treatment secondary to the high success rate of surgery.

There are 3 medical therapies:

1. Monthly injections of medications that mimic natural growth hormone inhibitors are effective in about two-thirds of patients. Sometimes, these medications may be used before surgery to try to shrink the tumors and is effective in roughly 40% of patients. Side effects include digestive problems such as loose stools, nausea, and gas in one third of patients. About 25 percent of patients develop gallstones, which are usually asymptomatic.  
2. Oral medications that spur the release of dopamine may help reduce growth hormone secretion in a small number of pituitary tumors.
3. A novel drug called Pegvisomant that acts as a growth hormone receptor may be a promising option for patients who do not respond to synthetic growth hormone inhibitors or other types of treatment. In selected patients, it may be considered as first line therapy. Pegvisomant is highly effective and may normalize IGF-1 hormone levels in up to 97% of patients. In some case, it may increase the size of the pituitary tumor. That is uncommon but MRIs are recommended to monitor the tumor. Pegvisomant may cause changes in liver function, so lab tests are recommended.

Radiation therapy for acromegaly is usually reserved for patients who have tumor remaining after surgery. At Stanford, radiation treatment is recommended very rarely, less than 5% of patients, given the success rate of surgery. These patients commonly also receive medication to lower growth hormone levels. Radiation therapy may be given in divided doses over four to six weeks. This treatment lowers GH levels by about 50 percent over two to five years.

In selected patients, radiation therapy may be given as highly focused, single or multiple treatments. Radiation therapy may cause a gradual reduction of pituitary hormone levels, resulting in hypopituitarism. While there have been some reports of vision loss or brain injury, these are very rare complications of radiation treatments.