New Learn about the hormones produced by the pituitary gland. The Pituitary Gland New How to find a qualified Surgeon

Acromegaly is a disease of growth hormone (GH) hypersecretion. Usually, the source is the pituitary tumor. These are always benign (non-cancerous) but often large and invasive. GH itself does not promote growth. Instead, it induces production of yet another hormone, IGF-I or somatomedin C (SmC) in virtually all organs and tissues. High IGF-I in turn promotes somatic growth. Clinically, acromegaly is associated with increased amount of soft tissues (large puffy hands, rough facial features), bone overgrowth (protruding lower jaw, frontal bossing) tall stature (if the disease began before puberty). Other symptoms include headache, sweating, snoring, sleep apnea, carpal tunnel syndrome and joint aches.

The development of the disease is insidious, and at the time of diagnosis the patient usually recalls the existence of symptoms for 5-10 years. Even family rarely notices the gradual development of the disease. Often, the diagnosis is made by a stranger or by a new physician during his/her first meeting with the patient.

Acromegaly is a potentially life-threatening disease: Life expectancy in the patients is shortened on the average by
10-15 years. Heart disease, diabetes and sleep apnea all contribute to excess mortality. It is also possible that certain cancers (colon, breast, and prostate) may be more frequent.

The biochemical diagnosis rests on the finding of high GH and IGF-I levels. Often, the reliance on GH confuses the picture: most laboratories state that GH below 10 or 15 ng/ml is normal. Physicians who are not experienced in pituitary diseases often tell the patient that the diagnosis of acromegaly is excluded if plasma GH is “normal.” In fact, active acromegaly may be accompanied by perfectly normal GH levels, often as low as 0.5-1 ng/ml. Over the past 5 years we have seen close to 20 such patients, whose diagnosis was missed elsewhere because of “normal” GH. We often put such patients in the Clinical Research Center to perform frequent blood sampling and do certain dynamic tests to establish the diagnosis with certainty. Currently, plasma IGF-I is the only valid measure of biochemical activity of the disease. If it is elevated, the diagnosis of acromegaly should be suspected. Similarly, only normalization of IGF-I can serve as a valid parameter of cure.

Surgery is the first option for the patients. It should be done by an experienced pituitary surgeon. A minimum of 20 pituitary surgeries per year is a criterion suggested by some to indicate sufficient experience and proficiency. In experienced hands, microadenomas are totally removed in 80-90% of cases, while the success rate in macroadenomas depends on the size and the invasiveness of the tumor. The success rate of less experienced surgeons is about ½-1/3 as low as that and the incidence of complications is 3-4 times as high. Very large and invasive tumors often cannot be removed surgically, but a sufficient debulking is important to improve the efficacy of subsequent treatments.

After transsphenoidal surgery the patient stays in the hospital overnight. Only rarely do we have to prolong hospitalization for another 2-3 days. Patients usually return to light work within a couple of weeks, but strenuous exertion is not recommended for a month. The recurrence rate is below 10%.

Radiation is very effective in preventing tumor regrowth, but its ability to normalize hormone levels is limited and takes years. Stereotactic radiosurgery (gamma knife) is a confusing misnomer as no surgery is involved. While it is becoming more popular, there is still no evidence that it is any more effective than conventional radiation in normalizing hormone levels. Also, it has a higher complication rate.

Medications are usually used in the majority of patients whose hormone levels are still high after surgery. Dopamine agonists (Parlodel, Dostinex) are convenient because of oral route of administration but their efficacy is quite low. Somatostatin analogs (octreotide or laureotide) normalize hormone levels in 50-80 % of patients. Currently, only monthly injections are needed.

A novel medication, GH antagonist pegvisomant " Somavert" has recently been shown to normalize IGF-I in more than 90% of patients. Somavert will be available soon for the public.

In conclusion, acromegaly is an insidious disease that is very dangerous if left untreated or undertreated. Fortunately, with modern technologies almost all patients can be treated successfully. This can be accomplished only in a center with vast experience in pituitary diseases and access to novel, often investigative, medications.

For more information about a new treatment for acromegaly visite Somavert.