The Importance of Long Term Follow Up After Endoscopic Pituitary Surgery: Durability of Results and Tumor Recurrence

Introduction: Endoscopic endonasal approach (EEA) has become the preferred surgical approach for resection of pituitary adenomas in most centers. This technique has a number of advantages such as improved visualization and maneuverability, when compared to microscopic transsphenoidal approach. However, the long-term results of this approach are still scarce. Ten years ago, we published our initial series of patients having undergone an endoscopic removal of their pituitary adenomas reporting favorable short-term results. This project aims to revisit the results of that series, addressing the long-term results regarding recurrence of pituitary adenomas.

Methods: A retrospective analysis of consecutive, endoscopically managed pituitary adenomas in a single center from 2004-2007. Only patients with >5 years of follow up (FU) and complete follow up data were included in this study. Recurrences were defined as evidence of any new tumor growth or enlargement of previously noted residual adenoma and/or biochemical recurrence of disease activity, in cases of functioning adenomas.

Results: A total of 98 patients matched the inclusion criteria for this study. The median follow-up period was 144 months. Nonfunctioning adenoma was the most common subtype (n = 66, 67.3%), followed by GH-secreting tumors (n = 19, 19.4%), ACTH-secreting tumors (n = 7, 7.1%), prolactinomas (n = 4, 4.1%) and TSH-secreting adenomas (n = 2, 2%). Age ranges from 23 to 82 years, with median age of 53 years. Preoperative visual deficits were observed in 46 patients (46.9%) and hormonal deficits were identified in 31% of cases. 22.4% of patients had undergone a previous pituitary adenomas resection prior to treatment in our center. Surgery achieved gross total resection (GTR) and near total resection (NTR) in 89 cases (90.8%) (56.1% and 34.7%, respectively). A total of 37 cases had recurrences during FU (mean recurrence free survival: 80 months). Recurrences were observed in 34% of patients who had had GTR while recurrences were observed in 39.5% of cases that underwent subtotal resection. Most recurrences occurred after 5 years of FU and univariate analysis demonstrated previous surgery (P = 0.005), cavernous sinus invasion (P = 0.05) and Ki-67 >5% (P = 0.01) to be factors associated with higher chance of recurrence. Multivariate Cox-regression analysis demonstrate that previous surgery and Ki-67 >5% are factors associated with recurrences. Surgery and/or radiation were utilized for management of recurrences in 29/37 cases.

Conclusion: Long-term FU analysis demonstrates that progression/recurrence of previously resected adenomas is observed in a significant number of patients, especially in those with previous/multiple surgical resections, elevated ki-67 and cavernous sinus invasion. Short-term FU may shadow real tumor control rates achieved after EEA and underscores the importance of long-term FU in these patients. Therefore, long-term FU should be pursued in all cases.