Growth and Invasion Patterns of Pituitary Adenomas: Correlations to MIB-1, P27, and FGFR4

Introduction: In this study, we aimed to gain a clearer understanding of the growth and invasion pattern of pituitary adenomas (PAs) and correlate the data with tumor proliferation and growth factors expression.

Materials: We reviewed 150 consecutive pituitary adenomas that were operated on at our institution for this study. We calculated pre- and postoperative tumor volume doubling time (TVDT) using two preoperative and two postoperative MRIs. We recorded cavernous sinus invasion using established Knosp criteria for all cases. Using univariate and multivariate analyses, we correlated growth rate; pattern of growth suprasellar, infrasellar, and posterior clival; and the extent of invasion into the cavernous sinus with expression profile of the MIB-1 LI, p27, and FGFR4.

Results: Clinically nonfunctioning tumors were found in 67% of cases, and 33% were functioning. There were 53% women and 47% men with an average age of 53 years (range, 25-87 years). The preoperative TVDT was positively correlated with patient age in both functioning and nonfunctioning adenomas. Preoperative TVDT was inversely correlated with the MIB-LI in nonfunctioning adenomas only. There were no correlations between preoperative or postoperative TVDT and p27, FGFR4, or any of the recorded growth patterns.

There were 36% residual adenomas following surgery, 62% of which grew over time. Preoperative TVDT did not predict postoperative TVDT or rate of growth of residual tumor.

Conclusions: Of all growth parameters and pattern of cavernous sinus invasion, we identified that a greater MIB LI was associated with faster preoperative tumor growth but not related to postoperative growth. None of the other factors were predictive of postoperative growth rate or recurrence.