Long-term outcomes of transsphenoidal surgery for management of growth hormone–secreting adenomas: single-center results
Authors: Asha Mohammed J. , Takami Hirokazu , Velasquez Carlos , Oswari Selfy , Almeida Joao Paulo , Zadeh Gelareh , Gentili Fred 
Published: October 2019

OBJECTIVE

Transsphenoidal surgery is advocated as the first-line management of growth hormone (GH)–secreting adenomas. Although disease control is defined by strict criteria for biochemical remission, the length of follow-up needed is not well defined in literature. In this report, the authors present their long-term remission rate and identify various predictive factors that might influence the clinical outcome.

METHODS

The authors conducted a single-institute retrospective analysis of all transsphenoidal procedures for GH-secreting adenomas performed from January 2000 to June 2016. The primary outcome was defined as biochemical remission according to the 2010 consensus criteria and measured at the 1-year postoperative mark as well as on the last recorded follow-up appointment.

Secondary variables included recurrence rate, patterns of clinical presentation, and outcome of adjuvant therapy (including repeat surgery). Subgroup analysis was performed for patients who had biochemical or radiological “discordance”—patients who achieved biochemical remission but with incongruent insulin-like growth factor 1 (IGF-1)/GH or residual tumor on MRI. Recurrence-free survival analysis was conducted for patients who achieved remission at 1 year after surgery.

RESULTS

Eighty-one patients (45 female and 36 male) with confirmed acromegaly treated with transsphenoidal surgery were included. In 62 cases the patients were treated with a pure endoscopic approach and in 19 cases an endoscopically assisted microscopic approach was used.

Primary biochemical remission after surgery was achieved in 59 cases (73%) at 1 year after surgery. However, only 41 patients (51%) remained in primary surgical remission (without any adjuvant treatment) at their last follow-up appointment, indicating a recurrence rate of 31% (18 of 59 patients) over the duration of follow-up (mean 100 ± 61 months). Long-term remission rates for pure endoscopic and endoscopically assisted cases were not significantly different (48% vs 52%, p = 0.6). Similarly, no significant difference in long-term remission was detected between primary surgery and repeat surgery (54% vs 33%, p = 0.22).

Long-term remission was significantly influenced by extent of resection, cavernous sinus invasion (radiologically as well as surgically reported), and preoperative and early postoperative GH and IGF-1 levels (within 24–48 hours after surgery) as well as by clinical grade, with lower remission rates in patients with dysmorphic features and/or medical comorbidities (grade 2–3) compared to minimally symptomatic or silent cases (grade 1).

CONCLUSIONS

The long-term surgical remission rate appears to be significantly less than “early” remission rates and is highly dependent on the extent of tumor resection. The authors advocate a long-term follow-up regimen and propose a clinical grading system that may aid in predicting long-term outcome in addition to the previously reported anatomical factors. The role of repeat surgery is highlighted.