No difference between initial radiotherapy or chemotherapy for oligoastrocytic tumors

CHICAGO – No significant difference was found between radiotherapy and chemotherapy for treatment of oligoastrocytic tumors, according to new phase-3 data presented today.

Wolfgang Wick, MD, department of neuro-oncology, University of Heidelberg and German Cancer Research Center, Heidelberg, presented the data June 2 at the 2008 ASCO Annual Meeting.

Wick and colleagues conducted the randomized study of sequential radiochemotherapy with PCV (procarbazine, lomustine and vincristine) or temozolomide (Temodar, Schering Plough) in WHO grade III oligoastrocytic tumors.

Three-hundred nineteen patients with anplastic astrocytoma, oligodendroglima and oligoastrocytoma were enrolled after central pathology review and randomly assigned to either initial radiotherapy treatment followed by chemotherapy at tumor progression (Arm A) or to initial chemotherapy treatment followed by radiotherapy at tumor progression (Arm B).

The goal of the study was to determine if chemotherapy should be given before or after radiotherapy.

Time to treatment failure was not statistically different between the two study arms (42.7 months in arm A vs. 43.8 months in arm B). There also was no difference in time-to-treatment failure between patients who were initiated on PCV vs. those initiated on temozolomide. Patients with pure astrocytic tumor had worse time-to-treatment failure.

Progression-free survival was also similar between patients started on PCV/temozolomide (30.6 months) and those started with radiotherapy (31.9 months).

Toxicity was not an issue in primary radiotherapy, according to the researchers, but was an issue, especially in the PVC arm, when chemotherapy was given first.

The researchers also found that especially hypermethylation of the methyl-guanyl methyl-transferase promoter but also loss of material on the 1p 19q chromosomal arms and hypermethylation of the methyl-guanyl methyl-transferase promoter resulted in a large time-to-treatment failure risk reduction regardless of the study arm. Most importantly, hypermethylation of the methyl-guanyl methyl-transferase promoter conferred a large risk reduction for PFS not only after chemo- but also after radiotherapy, indicating it to be prognostic rather than specific for alkylating chemotherapy.

Wick W. #LBA2007. Presented at: the 2008 ASCO Annual Meeting; May 30-June 3; Chicago.