Heterogeneity of oligoastrocytoma: morphology, surgery, and survival in the series of 163 patients. Retrospective study

Introduction. The current approach to oligoastrocytoma (OA) treatment includes surgery taking into account the anatomical and physiological accessibility using various radio- and chemotherapy protocols. Nevertheless, it should be recognized that influence of OA histological structure on the surgery of these tumors has not conclusively established. Objective. To improve diagnostic and surgical tactics in oligoastrocytoma by comparing determined clinical-histological patterns. Materials and methods. Retrospective clinical-morphological comparison and analysis of treatment results in 163 patients with OA were performed taking into account histological structure. OAII (WHO) was diagnosed in 32 patients (19.6 %), 131 patients (80.4 %) developed OAIII (WHO). Results. In 52 OA cases (32 %) oligodendroglial component (oOA) prevailed, in 48 OA cases (29 %) astrocytic component (aOA) prevailed, in 63 OA cases (39 %) there was relatively equal cells distribution of both components (оаОА). The surgical treatment of 163 patients included the following: gross total removal, 60 patients (31.4 %); subtotal removal, 98 patients (60.2 %); and partial removal, 4 patients (2.4 %). A total of 106 (65.0 %) patients presented with Karnofsky Performance Status Scale (KPS) ≥ 80. One hundred and fifty-three patients (93.9 %) experienced postsurgery KPS ≥ 80. There was no perioperative death. All 163 patients received radiation therapy and 87 patients (53.4 %) received chemotherapy as well. A significant difference (p< 0.05) in overall survival (OS) was found between surgery results of OA histological groups. Clinical and MRI/CT findings significantly correlated with histological types of OA as well as results of treatment: the overall survival in patients with oOA was 100.5 ± 4.6 months, aOA — 48.2 ± 4.5 months, oaOA — 76.6 ± 4.9 months, averaging 49.9 ± 2.4 months. Conclusions. Diagnosing, surgery, and survival of OA are determined by the uniqueness of the histological structure of these tumors, the interaction of their components, topography and expansion direction. The key to successful results is a differential approach to planning diagnostic tactics, method of removal and management in late post-op period.