Although grade 2 glial brain tumors (gliomas) constitute only 5 to 10 percent of all brain tumors, progressive neurologic symptoms and premature death result for nearly all patients diagnosed with this type of brain tumor.

The Radiation Therapy Oncology Group (RTOG), now conducting research as NRG Oncology, initiated the trial RTOG 9802 (A Phase III Study of Radiation With or Without PCV Chemotherapy in Unfavorable Low-Grade Glioma) in an effort to improve patient survival.

In the April 7 issue of The New England Journal of Medicine, NRG Oncology researchers report the long-term results of this randomized clinical trial, which demonstrate that patients who received radiation therapy (RT) plus a chemotherapy regimen including procarbazine, lomustine (CCNU), and vincristine (PCV) experienced a longer progression-free survival (PFS) and overall survival (OS) than those who received RT alone.

"This is the first phase III trial to demonstrate conclusively a treatment-related survival benefit for patients with grade 2 glioma," says Jan C. Buckner, M.D., the article's lead author, who is a professor of oncology at the Mayo Clinic College of Medicine and Deputy Director for Practice at the Mayo Clinic Cancer Center in Rochester, Minnesota.

"Our early study results, reported at a median patient follow-up of 5.9 years, showed that radiation therapy plus PCV chemotherapy was associated with a statistically significant prolongation of median progression-free survival, but not with overall survival."

Full methods and a breakdown of the patient cohort are published in the full article.

"Our results indicate that initial therapy of RT followed by PCV is necessary to achieve longer survival in patients with grade 2 glioma and that salvage therapy at relapse after RT alone is less effective," says Buckner. "It has also been hypothesized that other genetic alterations may be responsible for a small subset of patients whose glial brain tumors are chemotherapy-resistant. However, radiation therapy plus PCV appears to represent the most effective treatment identified to date for the majority of patients with grade 2 glioma," concludes Buckner.

"These results provide further clarification about how the histopathologic differences among low-grade gliomas correlate with their biologic behavior and progression. They also shed light on the most effective role and timing of radiation therapy and chemotherapy in prolonging progression-free and overall survival and minimizing morbidity in the younger age group of patients diagnosed with these brain tumors," says Walter J. Curran, Jr, M.D., the report's senior author, NRG Oncology Group Chairman, and Executive Director of the Winship Cancer Institute of Emory University in Atlanta.

Article: New England Journal of Medicine

Source: Mayo Clinic Cancer Centre