Background: Mammographic breast density (BD) has garnered clinical interest due to its impact on breast cancer (BC) risk, sensitivity of mammographic screening, and tumour size at presentation. There is conflicting evidence as to BD's effect on re-excisions and recurrence following breast conserving surgery (BCS). We hypothesize that increasing BD may obscure disease, resulting in an underestimation of the extent of disease, and a greater risk of re-excision and local recurrence following BCS for invasive BC.
Methods: A retrospective, population-based review of patients undergoing BCS for invasive BC between January 1, 2010 and December 31, 2016 was performed. Patients undergoing mastectomy as primary management, previous or recurrent BC, or who were lost to follow-up were excluded. Patient age, BI-RADS score, treatments, and pathologic findings were analyzed by Pearson's Chi-Square or Fisher's exact test for categorical variables and the Kruskal-Wallis test for continuous variables.
Results: 1371 and 1169 patients were eligible for re-excision and recurrence analysis, respectively. Higher BD is significantly associated with younger age, larger tumour size, and pathologic lymph node involvement. Multivariate analysis revealed no overall impact of BD on re-excision rate, though high BD (BI-RADS D vs A) was associated with a significant decrease re-excision rate (OR: 0.33, p = 0.019). No influence of BD on disease recurrence was observed.
Conclusion: Contrary to previous reports, high BD was associated with a decreased need for re-excision following BCS, which may be related to unmeasured factors. Increased BD was not associated with increased local disease recurrence.
Copyright © 2025 Elsevier Inc. All rights reserved.