October 10 (HealthDay News) -- Using chemotherapy alone, and delaying or avoiding radiation altogether, may be effective in treating children with inoperable or progressive low-grade glioma brain tumors, according to a multi-institutional study.

Low-grade glioma is the most common brain tumor in children. If surgery can be performed, the survival rate for patients is 95 percent. But prognosis is worse for children with tumors in locations that prevent surgical removal or with tumors that progress after surgery, according to background information in a news release about the study from the University of Texas M.D. Anderson Cancer Center in Houston.

Radiation is often used to treat children with inoperable or progressive low-grade gliomas. While radiation is often effective in treating these brain tumors, it can cause long-term effects such as mental impairment, hormonal deficiencies and increased risk of stroke later in life.

This new phase III study compared two different chemotherapy regimens, and confirmed that chemotherapy can be used to control inoperable or progressive low-grade gliomas in children, said principal investigator Dr. Joann Ater, a professor of pediatrics at the Children's Cancer Hospital at M.D. Anderson.

The study of 401 patients found that a regimen of thioguanine, procarbazine, lomustine and vincristine (TPCV) was more effective than a carboplatin and vincristine (VC) regimen and achieved a 5-year, event-free survival rate of almost 50 percent.

Patients aged 5 to 10 on the TPCV regimen averaged more than eight years without disease progression, compared to an average of 5.3 years among those who received the VC regimen. Patients younger than 5 on the VC regimen averaged 2.2 years before disease progression.

The study also found that chemotherapy was most effective among neurofibromatosis patients with low-grade gliomas.

"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 [radiation] treatment," Ater said. "This trial at least gives parents more information and alternative options when making decisions about their child's treatment."

The study was presented this week at the International Society of Pediatric Oncology annual meeting, in Berlin.

SOURCE: M.D. Anderson Cancer Center, news release, Oct. 6, 2008