Glioma is a type of brain cancer that is rare and difficult to treat. Until quite recently, gliomas were considered to be incurable and often became rapidly fatal, but now two trials have shown that the addition of chemotherapy to radiotherapy (RT) can improve both disease control and survival in the long term for patients with a glioma. The results* are reported in the Journal of Clinical Oncology today (Wednesday 22 June).
The two trials (EORTC 26951 and RTOG 9402) were launched 25 years ago. Patients with two types of glioma who had not undergone radiotherapy or chemotherapy were enrolled, and randomised to either RT with or without six cycles (EORTC) or four cycles (RTOG) of the chemotherapy drugs procarbazine, lomustine, and vincristine (PCV). In a joint paper, the researchers have now provided updates of these trials.
After a very long-term follow-up – a median of nearly 20 years – results from the EORTC trial showed that overall survival among patients randomised to PCV-RT as opposed to RT alone was 57% at 10 years, 51% at 15 years, and 37% 20 years after treatment in the first group as opposed to 43%, 26%, and 14% in the group that received RT alone. Results from the RTOG study were very similar. Progression-free survival (the time the patient lives without the disease getting worse) was also improved among patients with PCV-RT as opposed to RT alone.
“These trials have provided exciting, practice-changing results,” said Dr Martin van den Bent, from the Brain Tumour Centre, Erasmus University Hospital, Rotterdam, The Netherlands. “They also demonstrate the critical importance of publicly funded networks in conducting clinical trials, particularly where long intervals are required for the data to be fully mature. Such long-term trials are not feasible for a commercial sponsor, but they are essential if we are to be able to make progress in the treatment of rare diseases.”
It will be important to understand any long-term adverse effects of PCV-RT, the researchers say. Will there be effects on cognitive function? How long will patients be able to continue to live independently after treatment? Further trials are underway to study these issues. “But in the meantime, we are delighted to have been able to provide robust proof of the extension of disease-free and overall survival for these patients through the use of PCV-RT, and to show that the outlook for them is very much more promising than was thought as recently as a decade ago,” says Dr van den Bent.