Preoperative Treatment of Growth Hormone-Producing Pituitary Adenoma with Continuous Subcutaneous Infusion of Octreotide.

Abstract

Abstract. Preoperative therapy with octreotide, a long-acting somatostatin analog, suppresses GH hypersecretion, shrinks GH-producing tumors and leads to an improvement in subsequent surgical remission in acromegalic patients.A continuous infusion of octreotide has demonstrated more persistent suppression of GH secretion than intermittent injections, and only a few studies were reported on the effect of the tumor shrinkage with a continuous infusion of a small dose of octreotide. We therefore investigated the preoperative effects of small doses of octreotide (120-240 jig/day) administered continuously (with a subcutaneous infusion pump) over a short period (2 or 4 weeks) in nine untreated acromegalic patients. Octreotide therapy resulted in suppression of serum GH and IGF-1 concentrations in 8 out of 9 patients and reduction in pituitary tumor size measured by MRI in all patients (by 7.9 to 38.5%). In particular, considerable reduction in tumor size (more than 20%) occurred in 6 of 9 patients. In three patients assessed serially throughout the preoperative period, reduction in tumor size was noted within only one week after the start of octreotide therapy and reduction rate more than 20% was obtained within the first two weeks. In one patient, suprasellar tumor expansion totally disappeared after such therapy. Our results indicate that short-term continuous subcutaneous infusion of a small dose of octreotide results in not only inhibition of GH hypersecretion but also shrinkage of tumor size prior to surgery.

Meta-Analysis on the Effects of Octreotide on Tumor Mass in Acromegaly

“…The secondary endpoint was the relative reduction in tumor volume/mass from baseline evaluated in studies where these data were reported [19], [33], [34], [37], [38], [40], [42]–[44].…”

A Critical Analysis of Pituitary Tumor Shrinkage during Primary Medical Therapy in Acromegaly

“…No randomized, placebo-controlled trials measuring change in pituitary tumor size after primary therapy with somatostatin analogs were identified. Five studies employed diameter dimensions measured by MRI to assess tumor size change (1,6,7,11,15), nine studies employed tumor volume calculations (2-6, 8 -10, 12, 14), and in one study the measurement method was not described (13).…”

“…S OMATOSTATIN ANALOGS HAVE been successfully used to treat patients with GH-secreting pituitary adenomas because they are safe, effective, and usually well tolerated in the majority of patients (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Although these analogs are approved for use after noncurative pituitary surgery, wider experience has led to recommendations for their primary use in selected patients newly diagnosed with acromegaly.…”

Effects of Octreotide Infusion, Surgery and Estrogen on Suppression of Height Increase and 20K Growth Hormone Ratio in a Girl with Gigantism due to a Growth Hormone-Secreting Macroadenoma

“…Regression of tumor size was observed on MR imaging. Tamura et al [3]observed considerable tumor shrinkage within the first 2 weeks with continuous infusion even in a low dose of octreotide. Optimal dose and duration may be determined with regard to the maximal effect on tumor size.…”

“…Irradiation of the pituitary is undesirable during childhood, since it may permanently damage both pituitary function and the central nervous system. Continuous infusion of a subcutaneous somatostatin analogue (octreotide) can be applied to suppress GH secretion in pituitary gigantism/acromegaly [2, 3, 4]. …”