Anaplastic oligodendrogliomas: prognostic factors for tumor recurrence and survival

Anaplastic oligodendrogliomas (AO) are uncommon primary brain tumors whose natural history, prognosis, and optimal management are not yet fully understood. However, they are associated with a better prognosis and response to multimodality therapy based on specific molecular changes. In this multicenter retrospective study, we analyzed the clinical characteristics of patients with AO to identify prognostic factors that influence time to progression (TTP) and survival.

A retrospective search of the brain tumor databases of three institutions (the University of Texas M. D. Anderson Cancer Center, the University of California at San Francisco, and the University of Utah) for patients between 1977 and 1995 with histologically confirmed AO identified a cohort of 106 patients that was further analyzed in this study. Initial treatment included surgery alone (n = 12) or surgery followed by one of the following: radiotherapy (RT) alone (n = 49), chemotherapy alone (n = 4), chemotherapy followed by RT (n = 10), RT followed by chemotherapy (n = 20), and others (n = 11).

The median age at diagnosis was 43 years, and the median Karnofsky performance score (KPS) was 90. The overall median survival was 7.3 years, and the 5-year survival rate was 62%. Univariate analysis of several clinical variables showed that only age (p < 0.0001) and KPS (p = 0.04) correlated significantly with survival. Fifty patients had disease progression after initial therapy. The median TTP was 48 months. Age at diagnosis was the only variable that correlated significantly with TTP.

A trend towards longer survival with a greater extent of resection was evident. The relative efficacy of various treatment modalities could not be definitively determined because of the heterogeneity of the therapies used. Overall, patients with AO have a better prognosis after therapy compared with those who have other malignant gliomas.