This evidence-based series was developed by the Neuro-oncology of Cancer Care Ontario's (CCO's) Program in Evidence-Based Care (PEBC). The series is a convenient and up-to-date source of the best available evidence on adjuvant systemic chemotherapy, following surgery and external beam radiotherapy, for adults with newly diagnosed malignant glioma, developed through systematic review, evidence synthesis, and input from practitioners in Ontario.
Members of the Neuro-oncology Disease Site Group (DSG) agreed that, based upon the current evidence, it was reasonable not to recommend the routine use of adjuvant chemotherapy for patients with malignant glioma. Extensive consideration was given to the pre-treatment factors that might predict a higher chance of treatment response; nevertheless, even in patients with a predictably high probability of response to chemotherapy, there are no data from randomized controlled trials (RCTs) to confirm a survival advantage from adjuvant chemotherapy. In addition, the dilemma of expected survival gain versus treatment toxicity and impact upon quality of life remains unexplored. Ongoing randomized controlled trials will help to clarify the optimal timing of procarbazine, lomustine, vincristine (PCV) chemotherapy for the most chemosensitive group of patients, those with anaplastic oligodendroglioma. Newer schedules and new chemotherapy agents, such as temozolomide, are also promising. Some astrocytic malignant gliomas are chemosensitive (a minority) but which ones, or why, is not yet clear. At present, allowing individualized consideration of adjuvant chemotherapy for patients with anaplastic oligodendroglioma, anaplastic astrocytoma and young patients with any type of malignant glioma is a reasonable option. Implicit in the designation of chemotherapy as an "option" for these patient groups is the recommendation that patients be provided with information about the controversies surrounding the benefit and optimal timing of such chemotherapy. Participation in ongoing clinical trials should be encouraged.
In light of the new evidence from the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) CE.3 trial, the Neuro-Oncology DSG decided to revise its original recommendation which did not recommend the routine use of adjuvant chemotherapy.