- Design
- Systematic review with exploratory meta-analysis
- Population
- 1,718 patients in 13 studies of breast-conserving surgery
- Primary outcome
- Positive margin and re-excision rates
- Effect
- Positive margin RR 0.57 (0.36-0.88); re-excision RR 0.64 (0.40-1.04)
Standard breast MRI is acquired prone, but the operation is done supine, and the breast deforms between the two. This systematic review collected 13 studies, 1,718 patients, using supine MRI to plan breast-conserving surgery.
Positive margin rates with supine MRI ranged from 0% to 25.9%. In the five studies with a comparison group, supine MRI was associated with fewer positive margins (RR 0.57, 95% CI 0.36 to 0.88) and a reduction in re-excision that did not reach significance (RR 0.64, 0.40 to 1.04). Only one study was randomised, and most non-randomised studies carried a serious risk of bias.
The idea is sound and the early signal is encouraging, but it is not yet a reason to change routine protocols. Units with an interest in reducing re-excision could consider it within an audit or trial, alongside existing localisation techniques.
- Consider supine MRI for breast surgical planning only within an audit or research protocol for now.
- Discuss positional deformation with surgeons when prone MRI extent differs from the operative findings.
- Report lesion extent with fixed landmarks such as the nipple and chest wall to aid transfer.
- Track your unit's re-excision rate before and after any change in planning imaging.
Why it matters
It targets the mismatch between how the breast is imaged and how it is operated on.
Don't overread it
Only one randomised trial; the re-excision reduction did not reach significance.
The statistics, in plain English
A relative risk of 0.57 means about 43% fewer positive margins in the comparative studies. The re-excision interval (0.40 to 1.04) crosses 1, so a real benefit there is not shown.
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