Measuring medicine: How new technologies could help doctors predict patient outcomes

Researchers have found that functional diffusion mapping (fDM), which assesses early changes in tumors by diffusion MRI, can provide an earlier assessment of response for patients with glioma, a notoriously hard-to-treat cancer of the central nervous system.

“Diffusion MRI does not necessarily make a better picture of the tumor, but it may be able to assess the response of the tumor to therapy much faster than traditional MRI images,” said Brian D. Ross, Ph.D., co-director for the Center for Molecular Imaging at the University of Michigan. “In addition, by combining diffusion MRI and conventional MRI, one can get a better measurement of results than could be achieved with either test alone.”

Diffusion MRI is a type of magnetic resonance imaging scan that can be performed on any MRI system and which allows for the measurement of the movement of water within body tissue. It is commonly used to evaluate brain injury in stroke patients, and is gaining clinical popularity as a method for distinguishing different types of tissues or tumors.

In this study, researchers assessed brain tumor response by diffusion MRI in 60 patients with high grade glioma who were undergoing radiation therapy. The patients were assessed at one, three and 10 weeks after the start of radiation treatment. Researchers found measurable changes in diffusion MRI as assessed by fDM as early as the first week of treatment. Assessment at week three of therapy was a strong predictor of survival at one year. The strongest predictor was a combination of diffusion MRI and conventional MRI at week 10.

Ross says diffusion MRI is a better predictor of outcome at early stages of disease because it measures changes in cellular density. Researchers believe that a tumor responding to treatment will show decreased cell density, and, as a result, surrounding water will move more freely. Diffusion MRI enables physicians to see this water movement almost immediately instead of waiting the eight to 10 weeks traditionally needed to see if a particular treatment, such as radiation therapy, has shrunk a tumor, or if the tumor has grown.

This is a more accurate measure of tumor response than simply measuring the size of the tumor. “Tumors may appear to get larger or have more contrast enhancement as a response to therapy even if the tumor is not actually growing,” said Ross. “Diffusion MRI may help differentiate which patients are doing well even if the tumor grows.”

Presence of amphiregulin autocrine-loop predicts sensitivity of EGFR wild type cancers to gefitinib and cetuximab: Abstract 4958

Researchers have discovered a biomarker in epidermal growth factor receptor (EGFR) wild-type non–small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC) cell lines. This so-called amphiregulin autocrine loop appears to predict response to the targeted therapies gefitinib and cetuximab.

“Amphiregulin expression could, in fact, be a suitable biomarker to select patients with EGFR wild-type NSCLC who would be likely to benefit from gefitinib or erlotinib,” said lead researcher Kimio Yonesaka, M.D., Ph.D., a researcher at the Dana Farber Cancer Institute in Boston.