Tumor Resectability and Recurrence following Endoscopic Endonasal Transsphenoidal Pituitary Adenoma Surgery: A Single-Institution Experience

Background Pituitary tumors account for up to 15% of all intracranial tumors, 90% of which are adenomas. The surgical treatment of pituitary adenoma has undergone substantial changes since its inception insofar as the approaches to the sella and the surgical results and associated morbidity of surgery. However, an understanding of the results to expect from surgery based on tumor size has not been well described in the literature. The purpose of this study was to evaluate our institutional results for pituitary adenoma surgery done using the endoscopic endonasal transsphenoidal (EETS) approach.

Study Design Retrospective cohort, single institutional study.

Methods Institutional REB approval was attained for a retrospective review of all EETS cases for pituitary tumor resection since 2009. Queries of the hospital database were completed by medical records personnel to identify cases of pituitary tumors resected using the EETS approach. Patient characteristics, tumor type, endocrine data, and operation characteristics were then extracted from medical records pertaining to patient baseline characteristics. Preoperative MRI images were reviewed and the SIPAP classification applied to the pituitary tumors. Postoperative results were extracted for the duration of the follow-up period available for each patient. Results were analyzed using Chi2 test for categorical variables and t-test for continuous variables using STATA/IC v.12.1.

Results A total of 202 cases were identified; 57% of the cohort was male. The mean age of the cohort was 56 years old. Functional tumors were present in 29% of the cohort. Patients with a suprasellar or parasellar SIPAP score of 0 or 1 had radiologically confirmed complete resection of their tumor in 66.6% of cases, compared with 29% with a suprasellar or parasellar SIPAP score ≥2 (risk ratio: 2.3; CI: 1.58–3.39, p = 0.0005). When the tumor was completely resected radiologically, the mean time to recurrence was not different for the SIPAP of 0 or 1 group which was 27 months in comparison to 34 months for the group with a SIPAP score ≥ 2 (p = 0.13).

Conclusion In this cohort, a lower preoperative MRI SIPAP score was associated with a greater chance for radiologically confirmed complete resection of the adenoma indicating that less invasive tumors on preoperative imaging are more likely to be surgically completely resectable. Further, despite a more advanced preoperative SIPAP score, tumors that can be completely resected do not have a higher recurrence rate than less extensive or less invasive tumors. The results of our study can be used to better inform patients about their expected outcomes of EETS based on the preoperative MRI SIPAP score of their tumor.