Endocrine Abstracts

Objective: Early postoperative results for the Preoperative Octreotide Treatment of Acromegaly (POTA) study has been published, and like later randomized studies we demonstrated a beneficial effect of presurgical treatment with somatostatin analogues (SSA) in GH-secreting macroadenomas when evaluated 3–4 months postoperatively. However, concerns about a potential lingering effect of SSA and thereby potential false positive results have been raised. The objective of this study was to evaluate the long-term surgical cure rates.

Methods: Newly diagnosed patients were randomized to either 6 months pretreatment with octreotide LAR (n=32) or to direct surgery (n=30). Of them, 51 (26/25) had macroadenomas. The patients were evaluated 1 and 5 years postoperatively. Cure was defined as a normal IGF 1 level combined with nadir GH <2 mU/l in an oral glucose tolerance test, without having received postoperative treatment.

Results: The proportion of patients receiving postoperative acromegaly treatment was equal in the two groups both 1 and 5 years postoperatively. When using the combined criteria for cure, 10/31 (32%) of all adenomas and 10/26 (38%) macroadenomas were cured in the pretreatment group compared to 8/30 (27%) in total and 6/25 (24%) macroadenomas in the direct surgery group 1 year postoperatively (P=0.63 in total group and P=0.27 for macroadenomas). Five years following operation, the cure rate in the pretreatment group was 11/27 (41%) in total and 9/22 (41%) in macroadenomas versus 8/26 (31%) and 6/22 (27%) in the direct surgery group (P=0.45 and P=0.34).

Discussion: These long-term data from the POTA study does not prove a beneficial effect of SSA presurgical treatment. Still, in absolute numbers, an ~50% increase in cure rate is found. We can not exclude that this is due to lack of power resulting in a type 2 statistical error.