Using metabolic or molecular imaging to measure brain tumor patients' response to treatment is a powerful predictor of survival, notes a first-of-its-kind study presented at the 54th Annual Meeting of SNM, the world's largest society for molecular imaging and nuclear medicine professionals.
"Our study opens the door to the possibility that brain tumor patients may live longer and respond better to drug treatments," said Wei Chen, assistant professor in the Department of Molecular and Medical Pharmacology at the David Geffen School of Medicine, University of California, Los Angeles. "Malignant brain tumors are very difficult to treat. Typically, patients live for three months without treatment and up to a year with treatment," she said.
Using positron emission tomography (PET) imaging, with the radiotracer FLT (fluorothymidine), UCLA researchers were able to determine within one or two weeks after starting the treatment whether patients were responding well to the drugs bevacizumab and irinotecan. This quick response determination "is unheard of" with the traditionally used magnetic resonance imaging, a procedure that looks at the anatomy rather than metabolic activities of tumor cells, she explained. With MRI, it is often difficult to tell tumor growth from changes caused by treatment (such as radiation). In addition, it could take months before it's known whether a patient is responding to treatment, said Chen.
A brain tumor is an abnormal mass of tissue that grows and multiplies uncontrollably, taking up space within the skull and interfering with the brain's vital functions. Malignant brain tumors are rapidly fatal, said Chen. This year, nearly 21,000 people in this country will be diagnosed with brain and other related nervous system tumors in this country and nearly 13,000 individuals will die from them. Neurooncologists are desperately in need of an imaging modality that could evaluate reliably and rapidly the response to a treatment, she added.