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67%

52%

49%

OGGT, oral glucose tolerance test; GH, growth hormone.

OGGT, oral glucose tolerance test; GH, growth hormone.

which a large number of pituitary surgeries are performed by an experienced neurosurgeon report that achievement of a normal serum IGF-1 concentration ranges from 61% to 70%. Using the strict criterion of a postglucose GH of <1 ng/mL (^g/L) (2.5 mU/L), one study reported a 52% success rate. Table 1 summarizes the results from centers in which pituitary surgery is frequently performed.

In contrast, surgery in 73 patients performed by nine neurosurgeons in one community, (Manchester, England) resulted in an overall remission rate of 18% (39% for patients with a microadenoma, 12% for patients with a macroadenoma) (9). In comparing these results with those of dedicated pituitary neurosurgeons, the authors concluded that pituitary surgery should be performed by those with experience and expertise. Despite considerable surgical expertise, many patients are not cured, which relates to the size of the adenoma and invasion of adjoining structures (dura, bone, cavernous sinuses). Thus, additional treatment or treatments are necessary for symptomatic improvement and to reduce the risk of premature mortality.

Postoperative Evaluation

After pituitary surgery the patient should undergo measurement of serum IGF-1 (6 wk to 3 or more mo after surgery, delayed clearance of IGF-1) and an oral glucose test (can be performed within a week of surgery, short half-life of GH, approx 19 min) The definition of cure or remission is a serum GH of <1 ng/mL (^g/L) (2.5 mU/L) after glucose ingestion (8). A normal age- and gender-matched serum IGF-1 concentration is also the optimal outcome, if there is a discrepancy between the serum IGF-1 and glucose-suppressed GH value, the GH value should be used and the IGF-1 level measured 2 to 3 mo later. Persistent acromegaly requires additional treatment.

Table 2

Short-Acting Somatostatin Analog (Octreotide)

No. of Duration Serum GH <2.5 ^g/L Normal Author, year (ref.) patients Rx (mo) (6.5 mU/L) (%) IGF-1 (%)

Table 2

Short-Acting Somatostatin Analog (Octreotide)

No. of Duration Serum GH <2.5 ^g/L Normal Author, year (ref.) patients Rx (mo) (6.5 mU/L) (%) IGF-1 (%)

Ho, 1990 (17)

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