OCTREOTIDE FOR ACROMEGALY

Octreotide Before Surgery Improves Acromegaly Cure Rate

NEW YORK (Reuters Health) Sept 30 - A 6-month preoperative course of octreotide appears to improve the surgical cure rate in newly diagnosed acromegalic patients with macroadenoma, Norwegian researchers report in the August issue of the Journal of Clinical Endocrinology and Metabolism.

The researchers note that over the past 20 years, studies addressing the potential benefit of preoperative treatment using a somatostatin analog such as octreotide have shown conflicting results.

"Given present knowledge, I believe that all patients diagnosed with a macroadenoma should be pretreated according to our protocol before pituitary surgery, while patients with microadenomas should not," Dr. Sven M. Carlsen of the University Hospital of Trondheim told Reuters.

In this study, macroadenomas were defined as adenomas measuring more than 10 mm in the largest dimension on MRI.

Despite some caveats, Dr. Albert Beckers of the University of Liege, Belgium, agreed that these findings "support the view that SSA pretreatment may allow for greater long-term cure rates in subjects with acromegaly," he writes in an accompanying editorial.

The report was based on a prospective, randomized trial conducted between 1999 and 2004, in which all patients in Norway who were newly diagnosed with acromegaly were invited to participate. The 62 who did so were randomized to undergo transsphenoidal surgery directly (n = 30) or to receive octreotide 20 mg every 4 weeks for 6 months and then undergo surgery (n = 32). Octreotide was initially given subcutaneously and then intramuscularly.

Cures were determined by a follow-up 3 months post-surgery, based on the fasting level of insulin-like growth factor 1 (IGF-I) and on the level of growth hormone.

When cure was defined on the basis of IGF-I level, more pretreated patients (45%) than direct surgery patients (26%) were cured by surgery.

"In patients with macroadenomas, 13 of 26 (50%) pretreated vs. four of 25 (16%) with direct surgery were cured (p = 0.017)," the authors report.

Although previous studies had indicated that pretreatment with a somatostatin analog tends to soften adenomas, Dr. Carlsen's group observed the opposite, "a significant increase in the firmness of the adenomas." They also found, however, no evidence that this had any effect on the surgical outcome.

J Clin Endocrinol Metab 2008.93:2984-2990.