Preoperative somatostatin analogs treatment in acromegalic patients with macroadenomas. A meta-analysis

Several studies have investigated the biochemical remission rate of presurgical somatostatin analogs treatment on acromegaly, but the remission criteria were diversed and the results were contradicting.

Aim of this paper is to provide enhanced evidence for the effectiveness of preoperative SSA treatment to improve on surgical results of macroadenomas in acromegaly.

Literature is cited from the PubMed, Embase and Cochrane Library, dating from December, 1985 to August, 2013.

Eligibility criteria included patients with acromegaly caused by GH-secreting pituitary macroadenomas, patients pretreated with somatostatin analogs versus direct surgery and a stricter remission criteria defined as the GH nadir<1μg/l during an oral glucose tolerance test (OGTT) and the age- and sex- adjusted IGF-1 concentration was normal. Primary end points included Short term and long term postoperative biochemical remission.

A total of 1421 publications were found by the electronic search. After full-text review, 8 were included in our study. 7 of them focus on the postoperative remission in short term; 3 of them focus on the outcomes in long term. For the analysis of the postoperative biochemical remission, a random effect model was used to account for differences.

The meta analysis shows that patients in the SSA pretreatment groups have had a more significantly cure rate than those in the direct surgery groups (RR=1.72, 95%CI: 1.14-2.60, P=0.009) with a short term follow-up. Subgroup analysis proves benefit from lanreotide pretreated groups (RR=2.27, 95%CI: 1.34-3.84, P=0.002) but not octreotide pretreated groups (RR=1.51, 95%CI: 0.82-2.75, P=0.183). No significant differences appeared between the two groups (RR=1.03, 95%CI: 0.86-1.24, P=0.751) with a long term follow-up.

2 Retrospective trial was included and most of the trials included was designed as single-center study.

Based on the analysis of this paper, the preoperative SSA treatment was beneficial in the group with short-term follow-up, while it was not advantageous in the group with long-term follow-up. For the limitations in this study, to drawn more solid conclusions, further large, randomized, multi-center, and long-term follow-up trials were required.