PATH-48. KI-67 INDEX AS A PREDICTIVE MARKER OF MENINGIOMA CLINICO-PATHOLOGIC COURSE AND RECURRENCE FOLLOWING SURGICAL RESECTION: A RETROSPECTIVE STUDY

Abstract

Abstract BACKGROUND/OBJECTIVE Meningiomas are the most common primary intracranial tumor in adults. Although usually benign, they have a variable clinical course. 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, and meningioma recurrence. 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. Recurrence occurred significantly more frequently in tumors with a Ki67 index of 5 or more (31%) compared to those with a Ki67 index less than 5 (10.4%). Likewise, higher WHO grades were associated with a higher rates of recurrence, with rates of 11.3%, 27.9%, and 71.4% for grades 1, 2, and 3, respectively. Higher WHO grades also correlated with higher Ki67 scores (2.59, 10.01, and 20.71) for grades 1, 2, and 3, respectively. Additionally, a multivariate logistic regression model identified ki67, WHO grade and degree of resection as independent predictive variables for meningioma recurrence. CONCLUSION Our 10-year retrospective study suggests that the Ki67 index is a promising predictive marker for recurrence of intracranial meningioma following surgical resection. Our findings add to a growing body of data which supports inclusion of ki67 index in the WHO grading criteria.