The Impact of Preoperative MRI on Surgical Management and Disease-Free Survival in Ductal Carcinoma in Situ: A Propensity Score-Matched Study

Purpose

The role of preoperative breast magnetic resonance imaging (MRI) in the management of ductal carcinoma in situ (DCIS) remains controversial. This study aimed to evaluate the effect of preoperative breast MRI on surgical and oncologic outcomes in women with pure unilateral DCIS.

Methods or materials

We retrospectively reviewed 208 women with biopsy-proven, mammographically visible pure DCIS who underwent surgery at a single tertiary center between 2016 and 2022. Patients were divided into MRI and no-MRI groups. Propensity score matching (PSM) was performed using nine baseline covariates to balance the groups. Surgical outcomes and long-term disease-free survival (DFS) were compared in both unmatched and matched cohorts.

Results

MRI detected more extensive disease than mammography in 18% of cases, prompting changes in surgical planning. The MRI group demonstrated significantly higher rates of upfront mastectomy in both unmatched (19% vs. 2%, P<0.001) and matched (16% vs. 3%, P=0.009) cohorts. However, rates of positive margins, reoperations, and conversions to mastectomy were similar between groups. DFS was lower in the MRI group in the unmatched cohort (P=0.016) but not significantly different after matching (P=0.402).

Conclusion

Preoperative MRI in patients with pure DCIS was associated with more extensive surgery but did not improve surgical outcomes or DFS. These findings suggest that MRI may drive more aggressive treatment without clear oncologic benefit. Prospective trials are needed to define its role in personalized DCIS care.

Clinical Relevance/Application

Routine preoperative breast MRI for patients with pure DCIS should be reconsidered, as it may lead to surgical overtreatment—specifically increased mastectomy rates—without improving surgical margins or long-term disease-free survival.