Combined treatment modality for anaplastic oligodendroglioma: a phase II study

To investigate feasibility, toxicity and antitumor activity of combined surgery, postoperative radiation therapy (RT) and adjuvant chemotherapy (CHT) in adult patients with pure anaplastic oligodendroglioma (PAO) or mixed anaplastic oligoastrocytoma (MAO).

Between January 1988, and June 1993, 23 patients entered into a phase II study. After surgery, postoperative RT was administered with 60 Gy in 30 daily fractions in 30 treatment days in 6 weeks. Two weeks after RT, adjuvant 'modified' PCV (mPCV) (Procarbazine, 60 mg/m2, days 1-14; CCNU, 100 mg/m2, day 1; and vincristine, 1.4 mg/m2 (max. 2 mg), days 1 and 8) was administered every six weeks up to six cycles or until progression occurred.

Median survival time is not attained yet, while 1-5 year survival rates are 100%, 100%, 78%, 61%, and 52%, respectively. Median time to tumor progression is not attained yet, while 1-5 year progression-free survival rates are 100%, 100%, 70%, 52%, and 52%, respectively. On univariate analysis of potential prognostic factors, sex, tumor location (frontal versus other), and histology (pure versus mixed anaplastic oligodendroglioma) were not found to influence survival. Age of < 50 years carried improved prognosis as well as Karnofsky performance status (KPS) 90-100 when compared to KPS of 70-80. Patients having tumors < or = 4 cm did better than those with tumors > 4 cm as well as those with total tumor resection when compared to those with subtotal tumor resection or biopsy only. Acute high-grade (> or = 3) CHT-related toxicity was mainly hematological with only 3 (13%) patients experiencing acute grade 4 toxicity.

Combined treatment modality consisting of surgery, postoperative high-dose RT and mPCV chemotherapy for patients with anaplastic oligodendroglioma was effective with acceptable toxicity. Further studies are needed with more patients and longer follow-up to verify these results in this rare disease.