Recent research suggests that magnetic resonance imaging (MRI) may play a key role in breast cancer prognosis.
"Breast cancers are heterogeneous, and different subtypes of breast cancer will respond differently to therapy," said Sana Parsian, M.D., a research assistant in the department of radiology at the University of Washington in Seattle. "Every patient with breast cancer must undergo biopsy to be evaluated for the type of breast cancer they have. Based on that, adjuvant medical therapies are prescribed for them."
Parsian and her colleagues hypothesized that some quantitative magnetic resonance imaging (MRI) measures, such as diffusion-weighted MRI (DWI) and dynamic contrast-enhanced MRI (DCE), would correlate with histopathological markers by enabling the researchers to measure the tumor''s cellularity and vascularity.
In DWI, the diffusion of fluids along a field gradient reduces the MRI signal, so it can determine cellularity of the tumor by measuring the degree of water mobility. DCE enables viewers to see more information about tumor vascularity. A malignant cell group needs a blood supply to grow, and those vascular changes cause tumors to appear differently on DCE compared with normal tissue, Parsian said. The enhancement pattern seen on an MRI is called kinetics.
"When we looked at these measures, we realized there was a correlation with biomarkers," Parsian said.
Although these are preliminary data, she hopes that someday MRI might provide valuable noninvasive information about tumor biology for selecting and guiding targeted therapies.
Parsian said larger prospective studies are needed to confirm these results and that MRI may complement biopsy to sample the whole tumor and reflect tumor heterogeneity.
"I think the final goal of radiology is to get more information while doing the least amount of intervention possible for the patient," she said. "It would be great if we could improve our understanding of breast cancer biology and predict response to different therapies with imaging. Our study suggests MRI may play a valuable role in this process."