SAN FRANCISCO - Whether preoperative breast MRI contributes to better diagnostic accuracy and patient outcomes is one of the most controversial areas in breast imaging. The topic was explored in a discussion on September 13 at the American Society of Clinical Oncology's (ASCO) Breast Cancer Symposium (BCS).
Moderating the debate was Dr. Richard Bleicher of Fox Chase Cancer Center in Philadelphia; panelists included Dr. Constance Lehman, PhD, of the University of Washington in Seattle and Dr. Kathryn Evers, also of Fox Chase.
Addressing diagnostic questions
Although most would agree that breast MRI provides the highest level of cancer detection at an acceptable sensitivity, there's been quite a bit of controversy around using the modality preoperatively, Lehman told session attendees. Integration of MRI into surgical practices varies widely, surgical outcomes such as re-excision and mastectomy rates are also all over the map, and there's no definitive data supporting the idea that MRI improves patient outcomes.
"Why do we continue to offer preoperative breast MRI to our patients at our cancer center, when I'm freely admitting that we don't have definitive data on patient outcomes?" Lehman said. "The reason why we use it is for two very basic diagnostic questions: whether the woman has contralateral cancer -- 4% of our patients will -- and [for staging] the ipsilateral breast, as about 10% of our patients will have more extensive disease identified by the MRI."
The debate isn't about whether breast MRI finds more cancer, but whether it improves diagnostic accuracy and, thus, outcomes -- such as reducing the number of surgeries and cancer recurrences -- and whether it boosts survival rates. The answer remains unclear.
Lehman cited research presented at the 2011 RSNA conference by Dr. Liane Philpotts of Yale University, which found that reoperation rates were dramatically reduced across several different patient groups when breast MRI was used.
Reoperation rates after breast MRI
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But Philpotts also found that surgical outcomes vary widely, Lehman said.
Surgical outcomes with breast MRI
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So how can clinicians best manage patients with newly diagnosed breast cancer? Individual centers will have to decide, with their own audit data to guide them, which patients and providers may benefit from the improved diagnostic accuracy of disease extent that breast MRI offers, Lehman said.
Going forward, it's crucial to focus research efforts on how MRI can support more targeted treatment paradigms in select patients, such as the following:
- Offering lumpectomies rather than mastectomy for multicentric disease, and avoiding surgery for a subgroup of MR lesions
- Avoiding radiation therapy in prescreened patients
- Increasing the use of partial breast irradiation
- Informing decision-making regarding adjuvant therapy
Not enough evidence
The next panelist, Dr. Kathryn Evers, asked the question of whether breast MRI should be performed in all newly diagnosed cases, citing cost, increased patient anxiety, and possible delayed time to surgery as compelling reasons against breast MRI. But most important, she said, is that the evidence indicates that breast MRI does not improve surgical or survival outcomes.
"Nobody argues that breast MRI is a sensitive test that has the potential to improve the diagnosis and treatment of breast cancer," Evers said. "But should every woman with a new diagnosis have a breast MRI? I'm a radiologist, imaging is my thing, and I'd love to be able to say yes, but the current evidence says no."
Evers gave the session attendees an overview of the clinical research that has explored how breast MRI has affected margin status and conversion-to-mastectomy rates, as well as how it has estimated tumor size. Results are mixed and are based on single-center, retroactive trials.
Evers asked whether clinicians are posing the right questions about breast MRI.
"When we started doing a lot of breast MRI about 10 years ago, we thought of breast cancer as a monolithic entity," she said. "That's changed. One size doesn't fit all when you're talking about breast cancer. The answer to the role of MRI in breast cancer may lie in new imaging sequences and selective imaging based on tumor biology. More work still needs to be done to define the definitive role of breast MRI in this setting."
