RTOG Shows Early Aggressive Treatment Increases Survival for Some Brain Tumor Patients
Boston, September 22, 2008 - Early aggressive treatment with chemotherapy prior to radiotherapy may prolong survival for patients with anaplastic oligodendrogliomas according to new research from the Radiation Therapy Oncology Group (RTOG) presented at the American Society for Therapeutic Radiology and Oncology (ASTRO) 50th Annual Meeting in Boston. RTOG, an NCI-funded national clinical trials group, is a clinical research component of the American College of Radiology (ACR).
Longer-term results of an RTOG study show that administering chemotherapy prior to radiotherapy increased survival for oligodendroglioma patients. Progression-free survival also improved for those receiving the neoadjuvant chemotherapy, a benefit most evident in those whose tumors have deletions of chromosomes 1p and 19q.
"Our research, while providing some answers for patients with oligodendrogliomas, shows that longer follow-up and genetic profiles will be necessary to provide definitive answers for determining initial treatment strategies," related Gregory Cairncross, M.D., of the University of Calgary Foothills Medical Centre in Calgary, Canada.
RTOG 9402, a phase III study, enrolled 299 anaplastic oligodendroglioma patients from July 1994 until March 2002 at 104 academic and community facilities in the United States and Canada. Patients were randomized to receive either standard radiotherapy alone or four cycles of neoadjuvant chemotherapy using procarbazine, lomustine, and vincristine followed by standard radiotherapy. The unadjusted estimated five-year overall survival rate for all patients entered on the study was slightly better for those who received neoadjuvant chemotherapy (49 vs. 46 percent). The adjusted five-year survival rate is significantly different favoring the experimental arm (hazard ratio = 0.66; 95 percent confidence interval (0.46, 0.95); p value = 0.02). For progression-free survival, the unadjusted estimated five-year rate for all patients entered on the study was significantly better for those who received neoadjuvant chemotherapy (37 vs. 22 percent; p value = 0.003). The adjusted five-year overall progression-free survival was also significantly different favoring the experimental arm (hazard ratio = 0.57; 95 percent confidence interval (0.41, 0.79); p value = 0.02).
Molecular analysis of oligodendrogliomas divides these tumors into two groups - those with deletion of both chromosomes 1p and 19q and those without. RTOG research has shown that patients with the deletions have a better response to treatment and overall survival. RTOG 9402 data reports that patients with the deletion had a median survival of 8.7 years vs. 2.7 years for those without the co-deletion (p < 0.0001). Significantly longer progression-free survival was restricted to the 1p and 19q co-deleted group. Longer follow-up will be needed to determine whether neoadjuvant chemotherapy will significantly prolong the survival for those with 1p and 19q co-deleted oligodendrogliomas.
"RTOG's decades-long investigation of treatment strategies for brain tumor has led to exciting results. The role of personalized medicine is proving especially important for brain tumor research and RTOG is leading the way with several studies that use patients' molecular characteristics to determine treatment," said Walter J. Curran, Jr., the RTOG Group Chair, and the Lawrence W. Davis Professor and Chair of the Department of Radiation Oncology in the Emory School of Medicine and Chief Medical Officer of the Emory Winship Cancer Institute and the senior author of the study.
For more information or to arrange an interview with an RTOG spokesperson, please contact Sharon Hartson Stine at 609.458.5604, shartson@acr-arrs.org.
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ASTRO Abstract #16, A Randomized Trial of Chemotherapy plus Radiotherapy (RT) versus RT alone for Anaplastic Oligodendroglioma (RTOG 9402): The Perspective of Longer Follow-Up, is available at http://www.redjournal.org/article/S0360-3016(08)01000-6/fulltext.
In addition to Dr. Cairncross, authors include: M. Wang, Radiation Therapy Oncology Group, Philadelphia, PA; S. Chang, University of California San Francisco, San Francisco, CA; E. Shaw, Wake Forest University, Winston-Salem, NC; R. Jenkins, B. Scheithauer, and J. Buckner, Mayo Clinic, Rochester, MN; K. Fink, Baylor Health Care, Dallas, TX; M. Mehta, University of Wisconsin, Madison, WI; and W. Curran, Emory University, Atlanta, GA.
The multi-center study was coordinated by RTOG with participation from its member institutions and members of the Eastern Cooperative Oncology Group (ECOG), the National Cancer Institute of Canada Clinical Trials Group (NCIC), the North Central Cancer Treatment Group (NCCTG), and the Southwest Oncology Group (SWOG). The research was funded by National Cancer Institute grants CA21661, CA37422, and 32115.
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