Preoperative MRI May Overdiagnose Contralateral Breast Cancer

Preoperative magnetic resonance imaging (MRI) may lead to overdiagnosis of occult contralateral breast cancers (CBCs), according to a recent study published online ahead of print in the Journal of Clinical Oncology.¹

Researchers led by Shi-Yi Wang, MD, PhD, of the Yale School of Public Health in New Haven, CT, looked through the Surveillance, Epidemiology, and End Results Program-Medicare database to assess for synchronous and subsequent stage-specific CBC occurrence in 38 971 women who were diagnosed with stage 1 and 2 breast cancer from 2004 to 2009. Among the observed patients, 6 377 received preoperative MRI.

The researchers found that, upon propensity score matching and compared with women who did not undergo MRI, preoperative MRI use was significantly associated with higher synchronous CBC detection rate but lower subsequent CBC detection rate.

However, 5-year cumulative CBC incidence remained significantly higher among women who had undergone MRI compared to those who did not undergo MRI. Projected CBC events indicated that among 10 000 patients who would receive MRI, 192 in situ CBCs would be detected upon 5-year follow-up.

“An increased synchronous CBC detection rate, attributable to MRI, was not offset by a decrease of subsequent CBC occurrence among older women with early-stage breast cancer,” the authors concluded.

Reference

1. Wang S, Long JB, Killelea BK, et al. Preoperative breast magnetic resonance imaging and contralateral breast cancer occurrence among older women with breast cancer [published online ahead of print November 30, 2015]. J Clin Oncol. doi: 10.1200/JCO.2015.62.9741.