Correlation between Ki‐67 index and some clinical aspects of acoustic neuromas (vestibular schwannomas)

Abstract

Evaluation of the proliferation activity of neuromas has a practical meaning when there are doubts about the complete resection of the tumor. Evaluation of the clinical aspects connected with increased proliferation activity may have a much broader application. The aim of this study was to correlate selected clinical and radiologic aspects of vestibular schwannomas with the results of the Ki‐67 index. The studied group included 23 males and 20 females. Unilateral neuromas were stated in 38 cases (mean age, 52.2 years) and bilateral tumors in 5 cases (mean age, 44.2 years). The immunohisto‐chemical tests (Ki‐67) were performed on the specimens preserved in formalin and stored in paraffin. The Ki‐67 index was estimated in a semiquantitative study. The mean value of Ki‐67 index was 1.86%. In case of unilateral neuromas (n = 38), the average Ki‐67 index was 1.74%. In 5 cases of bilateral tumors, the index amounted to 2.79% (P = 0.278). No significant correlation was found by comparing the value of the Ki‐67 index with the age of patients (P = 0.410: r = 0.128). Significant differences in the value of the Ki‐67 index were noted in the subgroups of tumors that were evaluated radiologically as growing and stable. The mean value of Ki‐67 index was 3.17% in the first subgroup; in stable neuromas, it was significantly lower, amounting to 1.11% (P = 0.020). Such results may confirm that the growth rate of vestibular schwannomas varies and may explain the difficulties in estimating the growth of neuromas on the basis of clinical aspects only.