Preoperative octreotide treatment of acromegaly: long-term results of a randomised controlled trial

Objective: Randomised studies have demonstrated a beneficial effect of pre-surgical treatment with somatostatin analogues (SSA) in acromegaly when evaluated early postoperatively. The objective of this study was to evaluate the long-term surgical cure rates. Methods: Newly diagnosed patients were randomised to direct surgery (n = 30) or 6-month pretreatment with octreotide LAR (n = 32). The patients were evaluated 1 and 5 years postoperatively. Cure was defined as normal IGF1 levels and by normal IGF1 level combined with nadir GH <2 mU/l in an oral glucose tolerance test, all without additional post-operative treatment. A meta-analysis using the other published randomised study with long-term analyses on preoperative SSA treatment was performed. Results: The proportion of patients receiving post-operative acromegaly treatment was equal in the two groups. When using the combined criteria for cure, 10/26 (38%) macroadenomas were cured in the pretreatment group compared with 6/25 (24%) in the direct surgery group 1 year postoperatively (P = 0.27), and 9/22 (41%) vs 6/22 (27%) macroadenomas, respectively, 5 years postoperatively (P = 0.34). In the meta-analysis, 16/45 (36%) macroadenomas were cured using combined criteria in the pretreatment group vs 8/45 (18%) in the direct surgery group after 6-12 months (P = 0.06), and 15/41 (37%) vs 8/42 (19%), respectively, in the long-term (P = 0.08). Conclusion: This study does not prove a beneficial effect of SSA pre-surgical treatment, but in the meta-analysis a trend towards significance can be claimed. A potential favourable, clinically relevant response cannot be excluded.