Background: It is currently unclear whether adjuvant therapy for WHO grade III anaplastic astrocytomas (AA) should be carried out as combined chemoradiotherapy with temozolomide (TMZ)--analogous to the approach for glioblastoma multiforme--or as radiotherapy (RT) alone.
Patients and methods: A retrospective analysis of data from 90 patients with AA, who were treated between November 1997 and February 2014. Assessment of overall (OS) and progression-free survival (PFS) was performed according to treatment categories: (1) 50%, RT + TMZ according to protocol, (2) 11%, RT + TMZ with dose reduction, (3) 26%, RT alone, and (4) 13%, individualized, primarily palliative therapy. No dose reduction was necessary in the RT alone group.
Results: Median OS was 85, 69, and 43 months for treatment categories 1/2, 3, and 4, respectively. These differences were not statistically significant. PFS was 35, 29, 48, and 33 months for categories 1, 2, 3, and 4, respectively; again without significant differences between categories. In a subgroup of 39 patients with known IDH1 R132H status, the presence of this mutation correlated with significantly longer OS (p = 0.01) and PFS (p = 0.002). Complete or partial tumor resection and younger age also correlated with a significantly better prognosis, and this influence persisted in multivariate analysis. In the IDH1 R132H subgroup analysis, only this marker retained an independent prognostic value.
Discussion and conclusion: A general superiority of combined chemoradiotherapy compared to RT alone could not be demonstrated. Biomarkers for predicting the benefits of combination therapy using RT and TMZ are needed for patients with AA.