Predictive value of progression-associated chromosomal aberrations for the prognosis of meningiomas:: a retrospective study of 198 cases

Object. The goal of this study was to determine whether in meningiomas cytogenetic findings are suitable as a predictive parameter relevant to prognosis. Methods. Between 1992 and 1998 at the Department of Neurosurgery, Saarland University, 198 patients underwent surgery to resect meningiomas. The meningiomas were investigated cytogenetically and the patients were followed up for a mean period of 33 months. On the basis of the cytogenetic findings, the meningiomas were subdivided into four groups: Group 0 meningiomas displayed a normal diploid chromosome set; Group 1 tumors were found to have monosomy 22 as the sole cytogenetic aberrations Group 2 tumors were markedly hypodiploid meningiomas with loss of additional autosomes in addition to monosomy 22; and Group 3 meningiomas had deletions of the short arm of a chromosome 1, as well as additional chromosomal aberrations including loss of one chromosome 22. One hundred ninety-eight patients in whom tumor resections were determined to be Simpson Grade I or II could be followed up after complete tumor extirpation. In 20 patients, one or several recurrences were documented during the period of observation. The tumors were classified according to their different, but mostly uniform chromosomal aberrations. Recurrences were found in six (4.3%) of 139 tumors in Groups 0 and 1 and in two (10.5%) of 19 tumors in Group 2, the highest rate of recurrence was found in 12 (30%,) of 40 tumors in Group 3. This supports the notion that the deletion of the short arm of one chromosome 1 is an important prognostic factor in meningiomas. The results of this study document a significant correlation between histological grade (p < 0.0001), location (p < 0.0001), and recurrences of meningiomas (p < 0.0001) (significance determined using chi-square tests). Conclusions. The cytogenetic classification of meningiomas provides a significant contribution to the predictability of tumor recurrence and is, therefore, a valuable criterion for the neurosurgeon's postoperative management protocol.