Preoperative MRI use increasing in breast cancer

By Shreeya Nanda, Senior medwireNews Reporter

A Canadian research team reports a substantial increase in the use of preoperative magnetic resonance imaging (MRI) over a 10-year period in women with newly diagnosed breast cancer.

In 2003, preoperative MRI was used in 3% of women with a primary diagnosis of breast cancer who underwent breast-related surgery within 3 months of diagnosis. This rose to 24% in 2012, a significant eightfold increase that was observed across all disease stages.

Multivariate analysis showed that several factors were significantly associated with MRI utilisation, including younger patient age and higher socioeconomic status, higher disease stage, surgery performed at a teaching hospital and surgeons who more recently completed training.

Using data on 53,015 women from the Ontario Cancer Registry, researcher Angel Arnaout (Ottawa Hospital, Ontario) and colleagues also found significant correlations between postoperative MRI and short-term surgical outcomes.

Specifically, women who did compared with those who did not undergo MRI had a 2.52-fold increased likelihood of a greater than 30-day wait for surgery. The odds of undergoing mastectomy and contralateral prophylactic mastectomy were also higher, at 1.73-fold and 1.48-fold, respectively.

Preoperative MRI was also significantly associated with a higher probability of postdiagnosis breast imaging (hazard ratio [HR]=2.09) and biopsies (HR=1.74) as well as staging imaging for detecting distant metastases (HR=1.51).

The researchers note in JAMA Oncology that the observed increase in preoperative MRI utilisation is despite the lack of guidelines supporting its routine use and lack of robust evidence of benefit for short- or long-term surgical or oncological outcomes.

But editorialists Habib Rahbar (University of Washington, Seattle, USA) and Constance Lehman (Harvard Medical School, Boston, Massachusetts, USA) urge readers to interpret the results with “some caution”.

“Because the authors did not report MRI results (eg, if the MRI was interpreted as positive or negative), the extent to which the MRI might have influenced additional tests or more aggressive surgery is not clear.”

They also point out that Arnaout et al could not control for factors such as the capacity to offer breast reconstruction and patient genetic mutation status, which reportedly have a significant impact on treatment decision and “could be overrepresented in the MRI cohort”.

Rahbar and Lehman conclude by suggesting that future research could explore the role of MRI in novel treatment approaches, such as identifying patients eligible for multiple lumpectomies or for lumpectomy without radiation.

“It is this role in precision diagnostics and risk stratification that advanced imaging techniques may hold the greatest promise, and for which MRI should be studied in future prospective trials.”

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