Examining the rise of preoperative breast MRI

Despite being associated with more ancillary investigations, more mastectomies, and longer wait times before surgery, preoperative breast MRI (pMRI) has become significantly more common in recent years, according to a Canadian study published by JAMA Oncology.

Angel Arnaout, MD, of the Ottawa Hospital division of general surgery, and colleagues performed the study by analyzing data from over 53,000 patients with primary operable breast cancer. All patients were from Ontario, and treated from 2003 to 2012.

During that ten-year span, almost 15 percent of all patients had pMRI, and the frequency jumped from 3 percent of patients in 2003 to 24 percent in 2012.

Physicians have started turning to pMRI more frequently because of its ability to detect occult disease more accurately than traditional breast imaging methods. But the authors listed numerous other factors that should also be considered.

“Compared with mammography, breast MRI has a modest specificity that leads to higher false-positive rates, is more expensive, and requires the use of intravenous contrast medium,” the authors wrote. “In addition, randomized clinical trials, systematic reviews, and metaanalyses consistently show that pMRI fails to improve surgical outcomes, breast cancer recurrence rates, or survival. Moreover, pMRI has been associated with higher mastectomy rates.”

The authors presented several potential reasons for the increase use of pMRI.

“As with most medical technologies, ‘indication creep,’ in which indications for a test are expanded into areas beyond what has been evidence proven, is likely inevitable,” the authors wrote. “Other influences that may have contributed to this growth in pMRI use include the increased availability of MRI scanners, rising patient demand, institutional pressure to use expensive capital equipment, and potential radiologists’ self-referral for diagnostic imaging services.”

In addition, shown to be associated with pMRI use included younger age, higher socioeconomic status, surgeons with less experience and surgeons working at teaching hospitals.

Though pMRI is on the rise, the authors did note that the trend appears to be slowing down considerably.

“There seems to be a reduction in the rate of increase in pMRI in the later years ... a finding that has also been reported in some other studies,” the authors wrote. “This suggests that perhaps there has been an improvement in clinical alignment with clinical evidence and greater efforts at limiting resource use in an increasingly cost-conscious health care system.”

Another perspective

Habib Rahbar, MD, of the University of Washington Seattle department of radiology, and Constance D. Lehman, MD, PhD, of the Massachusetts General Hospital department of radiology, wrote an editorial that accompanied the study, also for JAMA Oncology.

In their article, Rahbar and Lehman wrote that many of the more negative aspects of pMRI mentioned by Arnaout’s team were logical when one considers how the technology is often used.

“The authors suggest that rising breast MRI use in women newly diagnosed as having breast cancer may contribute to a general problem of breast cancer overtreatment by prompting unnecessary additional imaging tests, biopsies, and mastectomies either in the affected breast or the unaffected contralateral breast,” Rahbar and Lehman wrote. “Because abnormalities identified on breast MRI require sampling prior to definitive treatment, it is not surprising that preoperative breast MRI prompts additional tests and biopsies, which in turn can lead to longer wait times between diagnosis and surgery. Furthermore, because MRI detects mammographically occult multicentric disease in roughly 10 percent of patients, and mastectomy is currently indicated for women with multicentric disease, it is logical that mastectomy rates would rise with its use.”

Rahbar and Lehman also looked at the potential role pMRI may have in healthcare’s future.

“High-quality diagnostic mammography supported the transition from mastectomy to breast-conserving surgery and radiation for patients with unifocal disease. Similarly, MRI may support the next advance in treatment options that are more targeted to the individual patient’s disease burden.”