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Is MR imaging appropriate for the surgical management of breast cancer?

Is MR imaging appropriate for the surgical management of breast cancer?

ABSTRACT: With a high sensitivity, MRI draws an accurate road map for planning surgical intervention. But the modality also suffers from a lack of evidence demonstrating an improvement in patient outcomes.

PHOENIX, Ariz.—Accurate local staging with imaging modalities is important for guiding breast cancer treatment in order to achieve clear margins and avoid recurrent disease.

But imaging also plays a part in detection of cancer in the contralateral breast. Whether MRI should be the go-to modality for staging primary disease and detecting contralateral breast cancer has yet to be determined.

The precise role and value of MRI in planning locoregional treatment and surgical management of breast cancer patients was debated at the 2009 Society of Surgical Oncology meeting.

On the pro side, Christiane Kuhl, MD, argued that MRI allowed for the most accurate delineation of size and extent of breast cancer. The modality also proves superior in detecting cancer in the contralateral breast, said Dr. Kuhl, vice chair, department of radiology and section chief, division of oncologic imaging and interventional therapy, at the University of Bonn, Germany.

On the con side, Monica Morrow, MD, stated that MRI does not improve outcomes, adds to the expense of treatment, and leads to unnecessary mastectomies. Dr. Morrow is the chief of breast service in the department of surgery and the Anne Burnett Windfohr chair of clinical oncology at Memorial Sloan-Kettering Cancer Center (MSKCC) in New York.

‘Breast surgeons require MRI’
MRI provides the most accurate road map for planning breast surgery in cancer patients, according to Dr. Kuhl. It has the highest sensitivity for depicting the size and local extent of breast cancer, including multifocal, multicentric, or contralateral disease. It is also useful for delineating intraductal extensions of breast cancers.

“We use MRI not only for patients with lobular cancer but also in those with ductal invasive cancer. There is increasing evidence that MRI is far more sensitive in delineating intraductal components (of breast cancers) than mammography or ultrasound,” Dr. Kuhl said.

She noted that MRI is extremely useful in finding additional multicentric breast cancer that would have been otherwise occult, as well as screening the contralateral breast for cancer in high risk women.

“This is the reason why our breast surgeons require breast MRI to be done in every patient with biopsy-proven cancer. We have daily dedicated time slots reserved for urgent, same day preoperative breast MRI studies. So there is no delay for surgery,” Dr. Kuhl said.

She explained that to be certified as a breast center, her institution must comply with European Union guidelines that state patients must undergo surgery within 10 days after a biopsy-proven cancer.

MR for diagnosis not screening
Dr. Kuhl said that a number of arguments against the use of preoperative MRI point out that there is lack of data on morbidity and recurrence rates. Furthermore, use of MRI in this context needs to be supported by the results from randomized trials.

Dr. Kuhl stressed that MRI is used in this context for staging; it’s a diagnostic tool rather than a screening modality. “Using MRI to find out the actual extent of disease doesn’t require randomized trials to support its use,” said said. “Randomization is only required to establish new therapeutic interventions or screening trials, but is not required to establish a new diagnostic test.”

She cited guidelines by the Oxford Institute of Evidence-based Medicine that only require randomized trials for establishing new therapies or screening but not for diagnostic situations.

“For diagnosis, a test only has to be consistently superior to current or established diagnostic tests. And there are a number of trials that show MRI is far more accurate in delineating the extent of known cancer compared with mammography or ultrasound,” she added (J Natl Compr Canc Netw 7:193-201, 2009; Top Magn Reson Imaging 19:143-150, 2008; Cancer 113:2408-2414, 2008).

Finally, using MRI allows clinicians to proceed straight to MRI-guided vacuum biopsy, which can often be done in the same diagnostic session. “MRI-guided vacuum biopsy is available to clarify additional lesions so there is no unnecessary anxiety for the patients and no unnecessary mastectomies for false-positive MRI findings. Also, there is no unnecessary cosmetic compromise due to additional excisional biopsies,” Dr. Kuhl said.

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