Chemo after radiation therapy improves brain cancer survival

Volume 3, Issue 2, 2014

Summary

A Mayo Clinic study shows significant improvement in overall survival for patients with low-grade gliomas.

Photograph of Jan C. Buckner, M.D., deputy director of cancer practice at the Mayo Clinic Cancer Center

Jan C. Buckner, M.D.

A clinical trial co-led by researchers at the Mayo Clinic Cancer Center and Wake Forest School of Medicine has found that adding a chemotherapy regimen following radiation treatment improves survival for adults with low-grade gliomas by about 5 1/2 years.

The study, RTOG 9802, enrolled 251 patients with low-grade gliomas between October 1998 and June 2002 to address the role of chemotherapy after radiation treatment. Patients enrolled were at high risk compared with other patients with a low-grade glioma because they either were age 40 or older or had an incomplete surgical removal of their tumor if they were younger than 40.

All patients started treatment with surgery and then had radiation therapy. After radiation therapy was completed, half the patients were randomly assigned to stop all treatment while the other half was randomly assigned to continue treatment with chemotherapy.

Patients receiving chemotherapy got three drugs: procarbazine, lomustine and vincristine. This chemotherapy combination, called PCV, was given over 21 days and repeated every eight weeks, for a total of six cycles.

Researchers noted a statistically significant improvement in overall survival for study participants who received PCV chemotherapy plus radiation therapy, compared with those who received only radiation therapy — 13.3 years median survival time vs. 7.8 years median survival time.

Median follow-up after initial enrollment has been almost 12 years. Analysis of how patients are doing based on the molecular and genetic characteristics of their tumors is ongoing. These studies will be important since molecular characteristics of related brain tumors have been able to identify patients most likely to benefit from chemotherapy.

"The results of this study are practice changing," said co-lead investigator Jan C. Buckner, M.D., deputy director of cancer practice at the Mayo Clinic Cancer Center. "Additionally, ongoing analysis of patient tumor samples should allow us to further identify the patients who will and who will not benefit from chemotherapy, taking yet another step toward individualized therapy."

Watch a video of Dr. Buckner discussing this study.