MGMT methylation status as a prognostic factor in anaplastic astrocytomas

Abstract

2052 Background: MGMT methylation status has been found to be an important prognostic factor in glioblastoma patients (pts). However, further data on the epigenetic feature are needed before its role in rare diseases such as anaplastic astrocytomas (AA) can be established. Methods: A retrospective analysis was made on a database of 139 AA pts followed prospectively from January 1995 and August 2008. We evaluated only pts who met the following inclusion criteria: age >18 years; PS 0–2; histological diagnosis of AA; postoperative radiotherapy (RT) and chemotherapy (CT). MGMT status was determined with methylation specific PCR. The study aim was to evaluate the role of MGMT methylation status in AA. The log-rank test was employed to evaluate the significance of the prognostic variables. Results: 80 pts (m/f: 46/34, median age: 41 years, range: 18–71 years) were enrolled. MGMT was assessable in 71 of 80 pts (88.8%), being methylated in 30 (42.9%), and unmethylated in 41 (57.7%) pts. Median PFS was 48.6 months (95% CI: 33.7 - 63.5), being 96 months (95% CI: 29–163) and 38 months (95%CI: 18.9–57.2) in MGMT methylated and unmethylated pts, respectively (p = 0.09). At univariate analysis, complete resection (p = 0.02), age (p = 0.002), and KPS (p = 0.003) were significantly correlated with PFS. At multivariate analysis only age remains correlated with PFS (p = 0.01). Median survival (OS) was 93.7 months (95% CI: 63.5–123.8), being not reached and 77 months (95% CI: 20–134.2), in MGMT methylated and unmethylated pts, respectively (p = 0.03). MGMT methylation (p = 0.03), age (p = 0.0003), and KPS (p = 0.03) were significantly correlated with OS at univariate analysis. At multivariate analysis, age (p = 0.0002) and MGMT methylation (p = 0.01) were correlated with a better OS. Conclusions: MGMT methylation status is an independent prognostic factor together with age in AA. This datum should provide the background to improve the therapeutic index with temozolomide concurrent with and adjuvant to RT in AA. No significant financial relationships to disclose.