Using chemotherapy alone and delaying or avoiding cranial radiation altogether can be effective in treating pediatric patients with unresectable or progressive low-grade glioma, according to a multicenter study presented Sunday at the 40th annual International Society of Pediatric Oncology meeting in Berlin.
“This is the first large, multi-institutional study to investigate using chemotherapy as an alternative to cranial radiation," said Joann Ater, MD, professor of pediatrics at the Children's Cancer Hospital at M.D. Anderson Cancer Center in Houston. “The results have confirmed the ability of chemotherapy to control the disease.”
Ater is principal investigator for the children's oncology group (COG) study and developed the Phase III trial, which compared two different chemotherapy regimens across three different patient groups. Smaller pilot studies have shown a carboplatin and vincristine (CV) regimen to be effective against low-grade glioma.
However, the COG trial, with 401 enrolled patients, found that a thioguanine, procarbazine, lomustine and vincristine (TPCV) regimen was more effective than the CV regimen and resulted in a five-year event-free survival rate of nearly 50 percent, according to the researchers.
Patients under five years old averaged 2.2 years before the disease progressed on the CV regimen, while patients between five and 10 years old, averaged 5.3 years before disease progression. However, patients on the TPCV regimen fared better, with those five to 10 years old averaging more than eight years without disease progression.
The trial also studied chemotherapy for neurofibromatosis patients who had low-grade gliomas, and found this population had the best response to chemotherapy among the three groups.
"If we can delay radiation, then we allow more time for our youngest patients to develop physically, which could decrease some of the long-term effects from treatment," Ater said. "This trial at least gives parents more information and alternative options when making decisions about their child's treatment."