We report on the long-term results of a phase II study of pre-irradiation temozolomide followed by concurrent temozolomide and radiotherapy (RT) in patients with newly diagnosed anaplastic oligodendroglioma (AO) and mixed anaplastic oligoastrocytoma. Pre-RT temozolomide was given for up to 6 cycles. RT with concurrent temozolomide was administered to patients with less than a complete radiographic response. Forty eligible patients were entered and 32 completed protocol treatment. With a median follow-up time of 8.7 years (range 1.1-10.1), median progression-free survival (PFS) is 5.8 years (95 % CI 2.0, NR) and median overall survival (OS) has not been reached (5.9, NR). 1p/19q data are available in 37 cases; 23 tumors had codeletion while 14 tumors had no loss or loss of only 1p or 19q (non-codeleted). In codeleted patients, 9 patients have progressed and 4 have died; neither median PFS nor OS have been reached and two patients who received only pre-RT temozolomide and no RT have remained progression-free for over 7 years. 3-year PFS and 6-year OS are 78 % (95 % CI 61-95 %) and 83 % (95 % CI 67-98 %), respectively. Codeleted patients show a trend towards improved 6-year survival when compared to the codeleted procarbazine/CCNU/vincristrine (PCV) and RT cohort in RTOG 9402 (67 %, 95 % CI 55-79 %). For non-codeleted patients, median PFS and OS are 1.3 and 5.8 years, respectively. These updated results suggest that the regimen of dose intense, pre-RT temozolomide followed by concurrent RT/temozolomide has significant activity, particularly in patients with 1p/19q codeleted AOs and MAOs.
Keywords: 1p/19q loss of heterozygosity; MGMT; Oligodendroglioma; RTOG; Temozolomide.