Study led by St. Jude finds that by tailoring the intensity of radiation to individual patients and cutting short the length of intensive chemotherapy improves outcome for those suffering medulloblastoma.
A team of investigators led by St. Jude Children's Research Hospital has announced that improved treatment measures for childhood brain cancer medulloblastoma have markedly enhanced the rate of survival of children with this disease.
The treatment increased the overall five-year survival for 86 children with average-risk medulloblastoma from the current rate of 70 percent to 85 percent; and raised the rate of survival among the 48 high-risk patients from 55 percent to 70 percent. Patients are considered to be at average risk of treatment failure if their cancer has not spread following initial surgery to remove the tumor, or if the remaining tumor is very small. Patients are considered at high risk of failure if their tumor has spread following surgery or if the remaining tumors are larger than those of low-risk patients.
Moreover, the improved treatment achieved a survival rate of 66 percent as compared to 30-40 percent among children whose cancer had spread.
The results of the current clinical trial, SJMB96, are especially significant because they represent a dramatic change from the 45 percent survival rate achieved two decades ago using just surgery and irradiation, according to Gajjar. The subsequent addition of chemotherapy before or after radiotherapy improved that survival rate to 65 percent for children aged 3 years or older who had medulloblastoma.
"We attribute our very promising results to the early use of high-dose radiotherapy after surgery--rather than waiting until after chemotherapy--in combination with short-term, intense chemotherapy," Gajjar said. "Shorter-term, intense chemotherapy is an especially important component of treatment that contributes to the improved survival of high-risk patients."
The researchers also showed that genetic differences exist in medulloblastoma tissues among children. These differences could be used to differentiate between children whose tumors are very aggressive and require novel experimental treatment and those children whose tumors are less aggressive and who could benefit from further reduction in treatment.
"These additional studies suggest that we can further reduce the long-term effects of treatment among some children by further reducing the treatment intensity," Gajjar said. The researchers previously reported that medulloblastoma consists of several distinct subgroups of this cancer that can be identified according to specific genetic abnormalities.