Ki-67/MIB-1 and Recurrence in Pituitary Adenoma

Objectives Ki-67/MIB-1 is a marker of cellular proliferation used as a pathological parameter in the clinical assessment of pituitary adenomas, where its expression has shown utility in predicting the invasiveness of these tumors. However, studies have shown variable results when using Ki-67/MIB-1 association with recurrence. The purpose of this study is to determine if a high Ki-67/MIB-1 labeling index (LI) is predictive of recurrence in pituitary adenomas. Methods A retrospective chart review was performed for patients undergoing pituitary adenoma resection with at least 1 year of follow-up. Additionally, systematic data searches were performed and included studies that correlated recurrence rate to Ki-67/MIB-1 LI. Our institutional data were included in a synthesis with previously published data. Results Our institutional review included 79 patients with a recurrence rate of 26.6%. We found that 8.8% of our patients had a high Ki-67/MIB-1 LI (>3%); however, high Ki-67/MIB-1 was not associated with recurrence. The systematic review identified 244 articles and 49 full-text articles that were assessed for eligibility. Quantitative analysis was performed on 30 articles including our institutional data and 18 studies reported recurrence by level of Ki-67/MIB-1 LI. Among studies that compared Ki-67/MIB-1 ≥3 vs. Conclusion This systematic review suggests that a high Ki-67/MIB-1 should prompt an increased duration of follow-up due to the higher odds of recurrence of pituitary adenoma.