Preoperative breast MRI features such as multifocal disease, a nonmass enhancement lesion, and greater background parenchymal enhancement can help forecast positive or close margins at breast-conserving surgery, according to a new study published in the August issue of the European Journal of Radiology.
The findings suggest that perhaps the reoperation rate could be reduced, as breast MRI could help surgeons better plan procedures, wrote a team led by Dr. Min Sun Bae, PhD, of Memorial Sloan Kettering Cancer Center in New York City.
"Breast MRI can improve depiction of [ductal carcinoma in situ] DCIS components, and MR-guided needle biopsy or MR-guided surgery may lead to improved surgical outcomes," the authors wrote.
Bae and colleagues sought to explore whether particular MRI features were associated with positive or close margins in patients with breast cancer who underwent breast-conserving surgery. The study included 249 patients with invasive ductal carcinoma who underwent preoperative MRI and breast-conserving surgery between 2008 and 2010 (Eur J Radiol, August 2019, Vol. 117, pp. 171-177).
The group characterized margins in the following manner:
- Positive (tumor touching the inked specimen margin)
- Close (< 2 mm tumor-free margin)
- Negative (≥ 2 mm tumor-free margin)
Of the 249 patients who underwent preoperative MRI before breast-conserving surgery, 33.3% had positive or close margins, the researchers found. As for features on MRI that predicted this outcome, Bae's group noted that multifocal disease, a nonmass enhancement lesion, greater background parenchymal enhancement, larger lesion size, and presence of DCIS on needle biopsy were independent predictors of positive or close margins according to odds ratios.
| Odds ratio of breast MRI variables for predicting positive or close margins at surgery | ||
| Variable | Odds ratio | p-value |
| Multifocal disease | 4.8 | 0.001 |
| Lesion type on MRI (mass vs. nonmass enhancement) | 3 | 0.003 |
| Background parenchymal enhancement | 2.5 | 0.023 |
| Lesion size on MRI in cm | 1.3 | 0.032 |
| Presence of DCIS on needle biopsy | 2.4 | 0.008 |
The study shows that several preoperative MRI features are associated with positive or close margins at breast-conserving surgery -- which could help surgeons better plan procedures, according to the group. In addition, the presence of DCIS on needle biopsy also increased the odds of a positive or close margin.
"These factors can be helpful in predicting the possibility of re-excision," the authors concluded. "Further prospective studies are needed to confirm our results."
