SAN ANTONIO—Breast MRI may have a role in preoperative management of primary breast cancer in special situations, but its routine use should be discouraged. So said Ismail Jatoi, MD, PhD, Professor and Chief of the Division of Surgical Oncology at the University of Texas Health Science Center at San Antonio, making the case here at the CTRC-AACR San Antonio Breast Cancer Symposium. He cited literature showing that it does not reduce the risk of reoperation, does not improve outcomes, and can lead to unnecessary use of ipsilateral and contralateral mastectomy.
“Primary breast cancer is a multi-centric disease at initial presentation; we've known that for a long time,” he said at an Educational Session. “Utilization of MRI in addition to traditional means of preoperative staging will only show what we've always known existed—that is, additional lesions outside the index quadrant away from the primary tumor.
“So, if you add MRI to the conventional imaging methods you will find additional disease, and this means you will be recommending more mastectomies.”
But more mastectomies do not necessarily mean better outcomes, he said, citing a meta-analysis he led that analyzed six trials and found no difference in survival between patients who underwent lumpectomy vs. mastectomy (Am J Clin Oncol 2005;28:289-294).
Moreover, when recurrences occurred, they tended to recur in the index quadrant, he said. “So why go to MRI if, in fact, trials show that despite the multicentric nature of breast cancer, lumpectomy vs. mastectomy gives equal outcomes?”
In another trial he cited, the COMICE trial (Turnbull et al: Lancet 2010; 375:563-571) researchers found that preoperative breast MRI did not reduce the rate of re-excisions in women with primary breast cancer who were scheduled for wide local excision.
Preoperative MRI can increase the risk of contralateral mastectomy rates, Jatoi said, noting that preoperative MRI detects additional disease beyond the index quadrant in 20 percent of women, of which 5.5 percent is in the contralateral breast.
He cited a recent meta-analysis of 50 articles surveyed to estimate the diagnostic accuracy of MRI in detecting additional lesions and contralateral cancer not identified using conventional imaging in primary breast cancer (Plana et al: European Radiology 2012;22:26-38). The analysis showed that true positive MRI findings prompted conversion from wide local excision to more extensive surgery in 12.8 percent of women, but that in 6.3 percent this conversion was inappropriate.
Those authors concluded that MRI shows high diagnostic accuracy, but that findings should be pathologically verified because of the high false-positive rate, and that future research on MRI should focus on patient outcome as the primary end-point.
“As a staging tool, MRI finds three to five percent of additional lesions in the opposite breast that are not evident on mammography ultrasound or clinical exam, but these additional lesions can very likely be treated with systemic therapy and conventional means,” Jatoi said. “Or, in many cases, they probably have no clinical significance.”
He added that there are, however, potential uses of MRI in breast cancer:
* Screening for women at high risk for breast cancer.
* Problem solving—for example, in patients who have malignant axillary adenopathy and no evidence of primary breast cancer on clinical exam, MRI very often will identify the primary breast cancer while mammography and ultrasound will fail to do so, he said.
* Monitoring response to systemic therapy.
* Evaluating patients with clinically concerning nipple discharge to identify potential lesions.
* Evaluation of breast implants, particularly when there is concern about a ruptured implant.
“But all these are outside MRI's very questionable role in the routine preoperative setting,” Jatoi concluded.