New ways of using magnetic resonance, led by University of Minnesota researchers and physicians, are being marshaled in the fight against breast cancer. Magnetic resonance imaging (MRI), used in conjunction with magnetic resonance spectroscopy (MRS), yields a wealth of information about breast lesions, leading to more accurate diagnosis and better treatment of breast cancer.
MRI is highly sensitive in detecting breast lesions of all kinds, yet an MRI is less able to determine whether a lesion is benign or malignant. However, by adding MRS, the chemical composition of the lesion may be identified. By measuring the amount of choline, a chemical compound common in cancer cells, it is possible to differentiate between benign and malignant tumors. MRS can also be used to determine whether a chemotherapy treatment is working to shrink the tumor, by measuring the choline levels before and after treatment. Combining the two magnetic resonance techniques in this way was developed by Michael Garwood, Ph.D., associated director of the University's Center for Magnetic Resonance Research (CMRR) and Doug Yee, M.D., Tickle Family Chair in Breast Cancer Research for the University of Minnesota's Cancer Center.
"Using high magnetic fields and spectroscopy is a powerful, non-invasive way to diagnose breast cancer and to monitor its response to treatment," says Garwood. "We hope this technique will eventually be used to avoid unnecessary biopsies." Yee agrees, adding: "As a physician, I'm excited about the ability of MRS to provide a quick and accurate gauge of whether the prescribed chemotherapy is working in a particular patient."
In a recent study, Garwood and Yee conducted choline measurements on patients before they received chemotherapy and 24 hours after the first dose (see images below). Patients who experienced a drop in choline within 24 hours had the most shrinkage of their tumor at the end of their treatment. "We believe choline can be an early indicator of a patient's response to chemotherapy," says Yee, "which could help oncologists tailor chemotherapy regimens for the individual patient to achieve the best response."
 |
MRI/MRS analysis of breast tumor response to chemotherapy. The MRI shows the tumor reduction following chemotherapy treatment of Adriamycian and Cyslophosphamide (AC). The graphs are the MRS (spectrum) measuring the reduction in choline. |
According to the American Cancer Society, more than 211,000 women in the United States will be told this year that they have breast cancer; more than 3,200 of them will be Minnesotans.
Garwood and Yee hope to take their research further by creating new technology that combines MRI and MRS into one unit that provides reasonably priced breast screening. They also are investigating ways to measure smaller volumes of choline in tumors and are working on replicating initial results in larger studies.
"We're optimistic that in a few years, we may see MRI/MRS technology play a significant role in breast cancer diagnosis and treatment," says Garwood.
