Medullablastomas Can Be Classified Noninvasively at Diagnosis
Medulloblastoma, the most commonly occurring malignant brain tumor in children, can be classified into four subgroups, each with a different risk profile requiring subgroup-specific therapy. Currently, subgroup determination is done after surgical removal of the tumor. Investigators at Children’s Hospital Los Angeles (CHLA) have now discovered that these subgroups can be determined noninvasively, using magnetic resonance spectroscopy (MRS). Their findings were published by Margol et al in Neuro-Oncology.
“By identification of the tumor subgroup at the time of diagnosis, we will be able to begin specific therapy earlier,” said Shahab Asgharzadeh, MD, of The Saban Research Institute of Children’s Hospital Los Angeles.
Treatment for medulloblastoma includes surgery, chemotherapy, and radiation, with 5-year survival rates ranging from 30% to 90%, depending upon risk profile.
Four Subtypes
A recent discovery identified four subtypes of medulloblastoma (SHH, WNT, Group 3, and Group 4) with level of risk and clinical outcomes for each subtype varying significantly. Currently, classification requires surgical removal of the tumor, followed by laboratory analysis of the tumor tissue. Given the clinical importance of subgroup determinations, a fast, reliable, and easily accessible method could have a significant effect on the outcomes of children with this disease.
“MRS is widely available, noninvasive, and provides information on cellular metabolism, which is different in healthy and diseased tissue,” said Stefan Bluml, PhD, Investigator at The Saban Research Institute of CHLA.
Study Results
Using frozen tumor tissue from 30 patients diagnosed with medulloblastoma, investigators performed subgroup analysis using standard techniques. These patients also had MRS performed at the time of diagnosis. With a screening panel composed of five metabolites, investigators found that the spectra for subgroups revealed distinct metabolic features, allowing them to differentiate subgroups SHH and WNT from Groups 3 and 4.
Clinical trials are being developed to incorporate molecular subgroups into risk and treatment stratifications. The ease of obtaining MRS at the time of diagnosis should allow its incorporation into future clinical trials aimed at validating this technique to improve diagnostic classification and, ultimately, improve outcomes in children with medulloblastoma.
This study was supported by the National Institutes of Health, the American Cancer Society, Alex’s Lemonade Stand Foundation, and the Rudi Schulte Research Institute.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
