Considerable deformity the breast and tumor position occur when placing patients in the prone (face down) position to obtain pre-operative MRI of the breast, compared with placing patients in the supine (face up) position, which is how patients are positioned for surgery for breast cancer.1

Traditionally, prior to breast-conserving lumpectomy for breast cancer, patients undergo a breast MRI in the supine position. It helps to inform the surgeon about the size, shape, and location of the tumor.

This phase 1 trial evaluated the differences between pre-operative prone and supine MRI examinations in 12 women who were undergoing lumpectomy for breast cancer. The patients underwent standard diagnostic MRI in the usual prone positive, then lumpectomy and postsurgical MRI in the supine position during the operation. Half of these patients had preprocedure supine imaging.

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Researchers found that specifications of the tumor, including size and location in the breast, were substantially different depending on the woman’s position for the pre-operative MRI. The tumors were all closer to the chest wall on supine images than on prone images. All patients underwent successful removal of their tumor with clear margins for invasive breast cancer.

“Accounting for change in size and shape caused by displacement and deformation of the tumor between standard imaging in the prone position and operative supine position, our analysis highlights that supine MRI before surgery may provide surgeons with more detailed and accurate information and could lead to effective tumor removal,” stated lead author Eva C. Gombos, MD, radiologist at Brigham and Women’s Hospital (BWH).

“Supine MRI, when performed in addition to standard prone breast MRI, may help detect a remnant tumor and ensure clear margins to prevent re-operation. Among women undergoing breast conserving surgery, 15% to 40% need to have a second operation to remove remnant tumor,” said Mehra Golshan, MD, distinguished chair in surgical oncology at BWH, and senior author of the study.

“If validated in future large studies, intra-operative, and, more importantly, pre-operative supine MRI could be expected to help the surgeon in accurately planning removal of the tumor and reducing the need for re-operation, which negatively impacts the patient emotionally, delays postoperative therapy, and increases infection rates and cost,” stated Gombos. The authors concluded that supine breast MRI imaging may help clinicians evaluate for residual tumor immediately after breast-conserving surgery.


1. Gombos EC, Jayender J, Richman DM, et al. Intraoperative supine breast MR imaging to quantify tumor deformation and detection of residual breast cancer: preliminary results. Radiology. 2016 Jun 22. doi:10.1148/radiol.2016151472. [Epub ahead of print]