MRI may be useful as noninvasive test of breast cancer prognosis
A preliminary study has shown that quantitative measures obtained by magnetic resonance imaging (MRI) are associated with prognostic tumor markers, suggesting that MRI can provide valuable noninvasive characterization of tumor biology in people with breast cancer.
A team led by Sana Parsian, MD, a research assistant in the radiology department at the University of Washington in Seattle, conducted a retrospective study of 41 cases of biopsy-proven invasive breast cancer (36 ductal and 5 lobular carcinomas) in 36 patients. All patients had undergone diffusion-weighted (DWI) and dynamic contrast-enhanced (DCE) breast MRI from October 2005 to May 2006 prior to treatment. DWI can measure the degree of water mobility in a tumor, thus determining cellularity, whereas DCE enables viewers to see more information about tumor vascularity.
The researchers found statistically significant correlations between MRI measures and histopathologic markers of breast cancer determined from biopsy, including progesterone receptor, HER2, p53, and the ki67 proliferation marker. Estrogen receptor was the only such marker with no statistically significant correlation with MRI; it was only marginally associated with one of the DCE measures.
Each of the DCE kinetics (the enhancement pattern seen on an MRI) parameters significantly distinguished grade III tumors from grade I and grade II tumors and luminal A from luminal B and basal-like intrinsic subtypes.
Larger studies are needed to validate these early findings, which were presented at the CTRC-AACR San Antonio Breast Cancer Symposium, held in San Antonio, Texas, December 6-10, 2011. In a statement describing the study results, Parsian expressed her hope that MRI might someday provide valuable information about tumor biology, obtained noninvasively, for selecting and guiding targeted therapies.