*3.5.1. Multimodal treatment*

also present [84]. Sarcomatoid areas can be seen. The minigemistocytes are more numerous than in the case of grade II oligodendrogliomas [85]. As a characteristic, the chicken wire aspect is accompanied by microvascular proliferation. As opposed to grade II oligodendrogliomas, they can involve palisading necrosis. Secondary structures can also be encountered. Immunohistochemically, the profile is that of grade II tumors, with a higher proliferation index evinced by way of Ki-67 (generally >5%). The differential diagnosis can be done using

**Figure 16.** Preoperative T2W and T1W+ C (a and b) sequences of a case with left frontal anaplastic astrocytoma completely removed; follow-up MRI performed at 4 months postoperatively and after concomitant radio- and chemotherapy with

**Log rank (Mantel-Cox) factor: type of surgery (gross total removal/ subtotal removal)**

12 months 0.000 0.000 0.090 0.296 18 months 0.000 0.000 0.122 0.836 24 months 0.000 0.000 0.031 0.756

**Table 1.** Disease free interval regarding the age, type of surgery, and histopathology.

**Log rank (Mantel-Cox) factor: histopathological diagnosis**

**Log rank (Mantel-Cox) factor: gender**

clear cell ependymoma, glioblastoma, and anaplastic astrocytoma.

temozolomide showed no signs of local recurrence (c and d).

**Disease free interval**

**Log rank (Mantel-Cox) factor: age (<65 years/≥65 years)**

114 Glioma - Contemporary Diagnostic and Therapeutic Approaches

As for the other types of gliomas, the grade of surgical resection is an independent factor for PFS and OS. As a consequence, GTR is recommendable wherever is possible without neurological damage (**Figure 17**).

**Figure 17.** Axial (a) and coronal (b) contrasted CT scan demonstrating the presence of a voluminous expansive lesion with large cystic components and peripheral calcification with a reduced perilesional edema, aspect highly suggestive for an anaplastic oligodendroglioma; after GTR the axial T2W (c) and coronal FLAIR (d) sequences at 2 years follow-up do not indicate a local progression.

Due to the good response of anaplastic oligodendrogliomas to chemotherapy, the subtotal resection with preservation of neurological function is also an acceptable surgical strategy [88].

### *3.5.1.1. Adjuvant treatment*

Adjuvant treatment is recommended in anaplastic oligodendrogliomas on a regular basis. Recent studies failed to demonstrate a benefit of temozolomide over the classical PCV regimen, which remains the main tool for first-line chemotherapy in anaplastic oligodendrogliomas. Radiotherapy is reserved for cases of clear imagistic evidence of tumor progress. Fractions of 1.8–2 Gy for a total dose of 54–60 Gy are the actual recommended radiotherapy regimen based on clinical evidence [89].
