Endocrine Abstracts

Introduction: Perioperative assessment of surgical outcome in acromegaly patients is essential due to significant persistence rate even after total adenomectomy. Grade of adenoma invasiveness and basal growth hormone (GH) level in early postoperative period have been considered as important factors.

Aim: The aim of our study was to evaluate the correlation between the outcomes of surgery in patients with acromegaly and the grade of adenoma invasion assessed by Knosp classification, and the level of postoperative 24-hour GH.

Materials and methods: Patients with GH-producing pituitary macroadenoma were included in the study. All patients underwent transsphenoidal surgery (TSS). The grade of parasellar invasiveness was assessed according to Knosp classification. A 24-hour postoperative GH level was measured in all patients. The results of TSS were evaluated 9 months after surgery. The biochemical remission of acromegaly was defined as nadir GH level on an OGTT <0.4 μg/l along with age and gender normalized values of insulin-like growth factor 1 (IGF-1).

Results: Nineteen patients (12 women and 6 men), mean age 47.0±13.2 years (27–64 years) were enrolled. The data on parasellar growth by Knosp classification was the following: Knosp grade 0 was in one patient; grade 1 in five; grade 2 in three; grade 3 in seven and grade 4 in three patients. Baseline GH level and adenoma size did not differ in patients with Knosp grade 0–2 and grade 3–4. Patients with Knosp grade 0–2 had lower 24-hour postoperative GH level than patients with Knosp grade 3–4 (2.3±3.1 vs 6.8±6.1 μg/l, P-value=0.041). Nine months after surgery, acromegaly remission was confirmed in 9/19 patients (47%). Six of 9 (66%) patients with remission had Knosp grade 0–2 and 3/9 (33%) patients with remission had Knosp grade 3–4. Seven of 9 (77%) patients with remission had 24-hour postop GH level <2.0 μg/l and 2/9 (22%) patients with level ≥2.0 μg/l. The remission rate had tendency to be higher in patients with 24-hour postop GH level <2.0 μg/l compared to group with Knosp grade 0–2: 7/8 (87.5%) vs 6/9 (66%), respectively, P-value=0.07. All patients with Knosp grade 3–4 and 24-hour postop GH level <2.0 μg/l had remission 9 months after surgery.

Conclusion: Our data suggests that 24-hours postoperative GH level <2.0 μg/l may be a stronger predictor of acromegaly remission after TSS than the grade 0–2 of adenoma invasion assessed by Knosp classification. These findings required further evaluation.