Preoperative breast MRI in HER2-positive/hormone receptor-negative breast cancer: surgical outcomes using propensity score matching.

OBJECTIVES

To examine the association between preoperative magnetic resonance imaging (MRI) and surgical outcomes in human epidermal growth factor receptor 2 (HER2)-positive/hormone receptor (HR)-negative breast cancer through a propensity score (PS)-matched analysis.

MATERIALS AND METHODS

Patients with HER2-positive/HR-negative invasive ductal carcinoma between 2007 and 2014 were retrospectively assessed and compared according to whether they underwent preoperative MRI. Inverse probability weighting (IPW) analysis and PS matching were used to adjust 17 covariates to control between the MRI and no-MRI groups. Surgical outcomes were compared between two groups and clinicopathologic variables were evaluated to determine who benefited from MRI.

RESULTS

Among 965 women (mean age ± standard deviation, 52 years ± 10), 423 (44%) underwent preoperative MRI and 542 (56%) did not. In the MRI group, a change in surgical management occurred in 48 patients (11%), and the change was appropriate in 31 of those patients (65%). The MRI group had a lower odds of initial mastectomy (odds ratio [OR], 0.63; 95% confidence interval [CI]: 0.47, 0.84; p = 0.002 and OR, 0.67; 95% CI: 0.48, 0.92; p = 0.01 for IPW and PS matching, respectively) and overall mastectomy (OR, 0.60; 95% [CI]: 0.45, 0.80; p = 0.001 and OR, 0.68; 95% CI: 0.49, 0.93; p = 0.02 for IPW and PS matching, respectively). In the subgroup analysis, asymptomatic patients or those with multifocal or multicentric lesions benefited more from MRI (61% vs 36%, p = 0.006 and 52% vs 31%, p = 0.02, respectively).

CONCLUSION

Patients with HER2-positive/HR-negative breast cancer who received preoperative MRI had a lower likelihood of undergoing mastectomy.

KEY POINTS

Question The role of preoperative MRI in predicting surgical outcomes in patients with HER2-positive/HR-negative breast cancer remains uncertain. Findings Preoperative MRI in HER2-positive/HR-negative breast cancer reduces mastectomy rates without increasing the positive resection margin or reoperation rate. Clinical relevance Preoperative MRI is beneficial in reducing mastectomy rates in women with HER2-positive/HR-negative breast cancer.