PROLIFERATIVE POTENTIAL OF RECURRENT INTRACRANIAL MENINGIOMAS AS EVALUATED BY LABELING INDEXES OF BUDR AND KI-67, AND TUMOR DOUBLING TIME

This study was designed to provide the reciprocal relationship among l abelling indices of 5-bromodeoxyuridine (BUdR LI), Ki-67 (KI-LI), and tumour doubling time (Td) of recurrent meningiomas. In our series of 1 82 primary intracranial meningiomas, 46 cases recurred. The average of BUdR LI and Ki LI for nonrecurrent meningiomas were 0.77 +/- 0.13% an d 4.71 +/- 1.96%, respectively. Recurrent meningiomas had significantl y higher LIs at the first operation: BUdR LI was 3.77 +/- 1.22% and Ki LI was 14.78 +/- 3.17%. The recurrent ratio significantly increased w ith the degrees of each LI. And the linear regression analysis has dem onstrated a significant correlation between BUdR and Ki LI. Td was cal culated accurately by NM, a computer software. Td showed a significant inverse correlation with each of the labelling indices. Consequently, BUdR, Ki LIs and Td of individual tumours correlate mutually well. Of the 46 recurrent cases, 4 received radiation after the operation. Td of the irradiated meningiomas tended to be longer than expected for th eir higher level of BUdR and Ki LIs before radiation therapy. Thus, it was shown that the radiation therapy delays the regrowth of meningiom as.