Ki-67 index as a predictive marker of meningioma clinicopathologic course and recurrence following surgical resection: a retrospective study

Abstract

Abstract Purpose Meningiomas are the most common primary intracranial tumors in adults. Although benign in a majority of cases, they have a variable clinical course and may recur even after a thorough surgical resection. Ki-67, a nuclear protein involved in cell cycle regulation, has been widely studied as a marker of cellular proliferation in various cancers. However, the prognostic significance of Ki-67 in meningiomas remains controversial. Here, we investigate the Ki-67 index, as a predictive marker of meningioma recurrence following surgical resection and compare it to established prognostic markers such as WHO grade and degree of resection. Methods The medical records of 451 consecutive patients with previously untreated cranial meningiomas who underwent resections from January 2011 to January 2021 at North Shore University Hospital (NSUH) were reviewed. Collected data included WHO grade, Ki-67 proliferative index, degree of resection — gross (GTR) vs subtotal (STR) — as judged by the surgeon, and meningioma recurrence. This study was approved by the NSUH Institutional Review Board IRB 21-1107 Results There were 290 patients with grade I, 154 with grade II, and 7 with grade III meningiomas. The average post-resection follow-up period was 4 years, and 82 tumors (18%) recurred. Higher WHO grades were associated with higher rates of recurrence, with rates of 11.4%, 27.9%, and 71.4% for grades 1, 2, and 3, respectively, and subtotal resection corresponded to a higher rate of recurrence than gross resection (34.3% and 13.4%, respectively). Higher WHO grades also correlated with higher Ki-67 scores (2.59, 10.01, and 20.71) for grades 1, 2, and 3, respectively. A multivariate logistic regression model identified Ki-67 and degree of resection as independent predictive variables for meningioma recurrence. Conclusion Our 10-year retrospective study suggests that the Ki-67 index is an important predictive marker for recurrence of intracranial meningiomas following surgical resection, particularly among patients with WHO grade 2 tumors. Our findings add to a growing body of data which supports inclusion of Ki-67 index in the WHO grading criteria for patients with meningiomas.