Presurgical octreotide treatment in acromegaly: no improvement of final growth hormone (GH) concentration and pituitary function. A long-term case-control study

Abstract

The effect of presurgical long-acting somatostatin analogue (SSA) treatment on operative outcome in acromegaly is as yet uncertain and long-term observations are lacking. We evaluated in an acromegaly case-control study the effect of octreotide pre-treatment on short- and long-term postoperative GH concentrations, pituitary function and glucose tolerance. 48 patients with a pituitary macro-adenoma - micro- and giant adenomas excluded - were evaluated. 24 patients received presurgical octreotide treatment (secondary surgery, prospectively studied). Another 24 thoroughly matched patients had been operated on without prior octreotide therapy (primary surgery, retrospective evaluation). No patient had received any other treatment prior to operation/octreotide. Standardized testing was performed at diagnosis, following octreotide treatment, after surgery and then yearly for 10.3+/-0.9 yrs (mean+/-SE, primary surgery) and 4.1+/-0.6 yrs (secondary surgery). Immediate and 4-year postoperative results were compared. All work-up was strictly identical in both groups, except for imaging techniques. "Partial remission" was defined as mean GH profile (6-h/7-point) concentration <2.5 microg/L, and "complete remission" as GH nadir <1 microg/L during OGTT plus normal IGF-I concentration (when available). The median profile GH (microg/L) values and the OGTT GH nadir values post-surgery (2.4/1.0 vs 1.8/0.7, primary and secondary surgery, resp.) as well as 4 yrs later (2.1/1.15 vs 2.3/0.8) were not significantly different between the groups. The 10-year results of the primary surgery group were not significantly different from its 4-year results. Subgroup analysis of pre-treated patients revealed no significant difference between those with and without tumour shrinkage, or between those with and without parasellar tumour extension. Postoperatively pituitary function was not significantly different between the groups. After 4-years the pituitary-adrenal axis was slightly more impaired in the secondary surgery group rather than following primary surgery, while the pituitary-gonadal axis was not different. Presurgical octreotide treatment has no significant short- or long-term beneficial effect on GH concentration or pituitary function.