The purpose of this study is to determine the efficacy and safety of temozolomide in patient with relapsed or advanced anaplastic oligodendroglioma and anaplastic oligoastrocytoma.

Patient with relapsed or advanced anaplastic oligodendroglioma and anaplastic oligoastrocytoma will be enrolled. Enrolled patients will begin on temozolomide 200 mg/m2/d in a fasting state for 5 consecutive days (1,000 mg/m2 per 28-day cycle). Patients who were previously treated with any chemotherapy initially received temozolomide 150 mg/m2/d for 5 days (750 mg/m2 per cycle).Patients will be receving a total 6 cycles of chemotheray (4weeks/cycle * 6cycles = 24weeks). If the patients shows responses to Temozolomide, treatment can be continued by the investigator's discretion.

During the administration of Temozolomide, vital signs, physical examination, ECOG performance status, height, weight, hematology and chemistry test, adverse events and concomitant drugs will be evaluated every four weeks. Brain MRI for tumor assessment will be performed once every 12 weeks.

Inclusion Criteria:

• Histologically proven anaplastic oligodendroglioma or oligoastrocytoma
• Progressed or relapsed after surgery or radiation therapy
• Female or male aged 20 years or over
• At least 1 measurable mass lesion
• ECOG performance status 0-3
• Adequate organ function
• absolute neutrophil count > 1,500/μL
• platelet count > 75,000/μL
• hemoglobin greater than 9 g/dL or 900g/L
• serum creatinine less than 1.5 times the upper limit of laboratory normal
• total serum bilirubin less than 1.5 times the upper limit of laboratory normal
• AST or ALT less than three times the upper limit of laboratory normal

Exclusion Criteria:

• Prior course of temozolomide
• Combined glioblastoma
• Pregnant woman