SUN-084 - Giant Pituitary Adenomas: A Single Center Experience of Surgical Treatment Strategies and Endocrine Outcome with 289 Patients

Objective.
This study aimed to evaluate surgical treatment strategies and results of giant pituitary adenomas, with a particular focus on complication rates and endocrine outcome in a single institution. The main surgical modalities included the transsphenoidal, the transcranial and the combined approaches.

Material and Methods.
A total of 289 consecutive patients who underwent primary surgery at our department between December 1982 and December 2022 were analyzed in this retrospective study. Giant adenomas were defined by a maximum diameter of ≥ 4 cm. There were 174 male (60.2%) and 115 female patients (39.8%) with a mean age at the time of surgery of 51.8 ± 16.4 years. 194 patients (67.1%) suffered from non-functioning adenomas, 44 patients (15.2%) from prolactinomas, 43 patients (14.9%) from acromegaly, 3 patients (1.0%) from Cushing's disease, 3 patients (1.0%) from functioning gonadotropinomas, and 2 patients (0.7%) from thyrotropinomas. Patients were reviewed for complication rates and endocrine outcome, especially in prolactinomas, acromegaly and Cushing’s disease.

Results.
The mean maximum tumor diameter was 4.6 ± 0.7 cm with a mean tumor volume of 33.6 ± 23.2 cm3. There were 201 patients (69.6%) undergoing transsphenoidal resection and 36 patients (12.5%) undergoing transcranial surgery only while 52 patients (18.0%) underwent a combined approach. Gross-total resection was achieved in only one-fifth (n=52) of the patients. The rate of total resection was dependent, among other factors, on tumor size and tumor extension. In this series 7 deaths (2.4%) occurred, in 4 cases due to postoperative tumor apoplexy. The cohort of the transsphenoidal surgeries only had the lowest rate of mortality (1.0%). Severe complications such as tumor apoplexy, meningitis or cerebrospinal fluid leaks occurred in 5.9%, 3.5% and 2.8% of patients, respectively. Postoperative hypopituitarism was the most common complication, affecting 34.7% of patients with no preoperative insufficiency. Endocrine remission was achieved after multimodal treatment in 21.1% and 24.0% of patients with prolactinomas (n=38) and acromegaly (n=32), respectively. No patient with Cushing's disease (n=3) achieved remission. The median follow-up time was 75 months. At the time of the last follow-up, a stable situation was present in 70.2% of patients.

Conclusion.
The treatment of giant pituitary adenomas still represents a significant challenge. In a minority of patients, a gross-total-resection or endocrine remission can be achieved, and the morbidity is high. It is important to consider individual patient and tumor characteristics when selecting the most appropriate surgical approach.

This study was supported by a grant of the Förderverein Neurochirurgische Forschung an der Universität Erlangen-Nürnberg e.V..

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