Prognostic significance of surgery and radiation therapy in cases of anaplastic astrocytoma: retrospective analysis of 170 cases

Abstract

The purpose of this retrospective study was to estimate the prognostic impact of treatment parameters for 170 patients with anaplastic astrocytoma (AA). Survival outcome and prognostic factors were analyzed for 170 patients with AA. In the multivariate analysis, site of lesion (frontal or parietal lobe, p = 0.002), extent of surgery (total or subtotal resection, p = 0.001), Karnofsky Performance Scale status (0-2, p = 0.021), age (< or = 50 years, p = 0.024), and total dose of radiation therapy (> 60 Gy, p = 0.029) were significant favorable prognostic factors. In the analysis of groups according to extent of surgery, patients who underwent total or subtotal resection had a significantly more favorable prognosis than did patients who underwent partial resection or biopsy (5-year survival rate 54.0% for total or subtotal resection compared with 17.5% for partial resection or biopsy; median survival time [MST] 62.6 months compared with 22.9 months [p < 0.0001, log-rank test]; hazard ratio [HR] 0.67; and 95% confidence interval [CI] 0.52-0.85 [p = 0.001]). In the analysis of groups according to total radiation dose, the group of patients who received doses greater than 60 Gy had a significantly more favorable prognosis than did the group who received 60 Gy or less (5-year survival rate 45.0% for patients who received doses greater than 60 Gy compared with 21.1% for those receiving 60 Gy or less; MST 48.9 months compared with 21.6 months [p = 0.0006, log-rank test]; HR 0.96; 95% CI 0.93-0.99 [p = 0.029]). The most important parameter in the treatment of AA was extent of surgery, and total radiation dose was the second most important factor. Resection of as much of the tumor as possible and delivery of a total radiation dose of greater than 60 Gy seem to be required for local control of AA.