Brain tumors in Mexico: characteristics and prognosis of glioblastoma.

BACKGROUND: Frequency and clinical characteristics of brain tumors have been studied in several populations from different genetic backgrounds; their peculiarities in the Mexican mestizo population shed light on the descriptive and comparative epidemiologic analysis of the genetic participation in brain tumors.
METHODS: To analyze the frequency of intracranial neoplasms at the National Institute of Neurology and Neurosurgery of Mexico between 1987 and 1994, demographic, clinical, surgical, and neuropathological records were reviewed and compared with other reports. Glioblastoma cases were followed to investigate survival and prognostic factors.
RESULTS: In a seven-year period 1,776 patients with brain tumors were treated; 419 (24%) had pituitary adenoma; 586 (33%) had glioma. Of the latter, 165 had glioblastoma multiforme, representing 28% of all gliomas and 9% of all neoplasms. Mean survival for glioblastoma was 16 months and the longest mean survival was obtained in patients with radical neurosurgical resection plus radiotherapy and chemotherapy. Cumulative analysis showed that 41% of patients survived less than one year, 39% from 1 to 2 years, 12% from 2 to 3 years and 8% more than three years. Factors that showed prognostic significance were age, therapeutic approach, tumor size, and pre- and postoperative clinical status (p < 0.05).
CONCLUSIONS: This study comprises the largest series on the frequency of brain tumors in a Latin American population. When compared with other studies, the proportion of glioma and glioblastoma among brain neoplasms was low whereas pituitary adenoma was high. Mean survival for glioblastoma was similar to other reports; in these patients, the overall therapeutic response is still far from satisfactory.