(NaturalNews) Children diagnosed with the most common type of pediatric brain tumor are significantly more likely to die from radiation treatment than from the tumor itself, according to the first comprehensive, large-scale cohort study of long-term survival in such patients.
The study into 20-year survival rates among children diagnosed with low-grade gliomas was conducted by researchers from Dana-Farber/Boston Children's Cancer and Blood Disorders Center and published in the journal Pediatric Blood & Cancer.
"We found for the first time that once you survive your childhood with a low-grade glioma, you are not likely to die of that tumor as an adult," senior author Peter Manley said. "This is incredibly encouraging for patients and families. However, we also found some things that we are currently doing to treat low-grade gliomas, such as radiation, are increasing the rate of death later, so that as an adult you won't die of the tumor, but you may die from the treatment."
High survival rates
Low-grade gliomas are a family of non-cancerous and typically non-aggressive tumors, including pilocytic astrocytomas, diffuse astrocytomas and mixed gliomas. Approximately 30 percent of pediatric brain tumors are low-grade gliomas. These tumors are usually treated with a mix of surgery and chemotherapy, since radiation to the developing brain has been linked to severe long-term consequences, particularly for cognitive development and the endocrine system.
Since the mid-1990s, in fact, doctors have increasingly avoided treating childhood cancers and tumors with radiation, and numerous hospitals (including Dana-Farber/Boston Children's) have eliminated the practice completely.
With low-grade gliomas in particular, researchers have long suspected that the risk of radiation treatment might outweigh the benefits. Even prior to the most recent study, the 5- and 10-year survival rates for low-grade gliomas were known to be about 90 percent
In the new study, the researchers used data from the National Cancer Institute to analyze 20-year survival rates in 4,000 people who had been diagnosed with pediatric low-grade gliomas between 1973 and 2008. Of those included in the study, 18 percent had received radiation treatment.
Cure worse than the disease
While 90 percent of all patients studied were still alive 20 years after treatment, only 70 percent of those who had received radiation treatment were still alive at that time. Although certain other factors were also found to affect survival rates (including age at diagnosis, year of diagnosis and location, type or aggressiveness of tumor), none affected the survival rate as strongly as whether radiation therapy had been used.
"There is an impression that children diagnosed with anything more aggressive than a grade 1 tumor do poorly in the long term," Manley said. "However, we found regardless of whether the diagnosis is grade 1 or grade 2, children with low-grade gliomas still do well."
Survival rates were also equally high among children who had only part of a tumor removed and those who had the entire tumor removed.
Based on the current study, the researchers recommend that doctors only use radiation as a treatment for low-grade gliomas as a last resort.
"We strongly recommend treatments that are less likely to cause long-term effects and second cancers," Manley said. "According to our analysis, radiation was the most common factor linked to differences in mortality among long-term survivors," he added. "There are multiple options available today for treating children with these tumors. We should exhaust all those before considering the use of radiation."
The study received funding from the Stop & Shop Pediatric Brain Tumor Program, the Andrysiak Fund for LGG, the Pediatric Low-Grade Astrocytoma Foundation, Friends of Dana-Farber Cancer Institute, the Nuovo-Soldati Foundation, the Philippe Foundation and the St. Baldrick's Foundation.