As the staging and treatment of breast cancer continues to evolve, the evidence of MRI's particular usefulness in this arena continues to mount.
Accurate assessment of tumors prior to breast-conserving surgery has become increasingly important, particularly as more patients undergo neoadjuvant chemotherapy to shrink tumors that would otherwise be too large for such surgery. And to meet this need, more researchers are finding that MRI is the superior imaging tool.
Some of the latest evidence came just last month, at the 22nd annual San Antonio Breast Cancer Symposium, cosponsored by the University of Texas Health Science Center, National Cancer Institute and others.
Brazilian investigators at the meeting reported on a study showing MRI's advantage over ultrasound in evaluating the impact of neoadjuvant chemotherapy on tumors ranging from 3.5 cm to 13 cm.
"The MRI is superior to ultrasound in tumor imaging measurements," said Dr. Maira Caleffi, professor of surgery at the Breast Institute of Rio Grande do Sul, in Porto Alegre.
"The images are especially helpful in allowing us to see separate tumors in a group," Caleffi said, noting that MRI can depict individual lesions where other modalities may only show an area of suspicious growths.
Caleffi presented data on 23 patients aged 25 to 62 -- mainly premenopausal women -- who were treated with neoadjuvant chemotherapy for stage II and stage III breast cancer, and then underwent imaging studies to determine extent of response.
Comparing the imaging findings to pathological assessment of tumor size, she reported an 85% correlation in size gauged by MRI compared to 60% correlation by ultrasound. Combining the imaging modalities did not improve the correlation, Caleffi said.
In another study reported in the Journal of Clinical Oncology last year, researchers from the University of California, San Francisco reported that MRI accurately predicted the extent of breast cancer in 54 of 58 patients prior to surgery and subsequent pathologic confirmation. J Clin Oncol 1999 Jan 17 (1):110-9
The extent of the cancer was also more accurately defined with MRI compared with mammography (98% to 55%). "Magnetic resonance imaging added the greatest value in cases of multifocal disease," the authors wrote. The triple-acquisition rapid-gradient-echo MRI technique was used to maximize anatomic detail.
"Based on preliminary data from our series, MRI would be valuable as a staging tool in the preoperative setting even if the cost is in the range of $1,300 to $2,000," the authors concluded. "It is already significantly less than the target cost, so it is reasonable to refine this technique for clinical use to help plan the most appropriate surgical intervention and possibly reduce costs as well."
By Edward Susman
AuntMinnie.com contributing writer
January 26, 2000
Copyright © 2000 AuntMinnie.com
