The value of a positive margin for invasive carcinoma in breast-conservative treatment in relation to local recurrence is limited to young women only

Purpose: To identify the importance of positive margins for invasive carcinoma on local control in patients treated with breast-conservative treatment (BCT). Methods and Materials: A total of 1752 BCT with known margins were analyzed. Fifty-five patients had a second BCT, leaving 1697 patients for analysis. The margins were positive in 193/1752 BCT (11%). The median follow-up was 78 months. Results: The 5- and 10-year local recurrence rates (LRR) were 3.1% and 6.9%, respectively, for negative margins vs. 5.6% and 12.2% for positive margins. A statistical interaction between age category and margin status was noted in relation to disease-free survival (DFS) and local relapse-free survival. The 5-year LRR for women ≤40 years was 8.4% for negative margins and 36.9% for positive margins (p = 0.005). In a multivariate analysis, a positive margin was significant. The 5-year LRR for women >40 years was 2.6% for negative and 2.2% for positive margins. The 5-year DFS for women ≤40 years was 27.4% for positive and 74.5% for negative margins (p = 0.001). The 5-year DFS for women >40 years was 84.3% for positive and 87.2% for negative margins. Conclusion: Women ≤40 years are a special category of patients in breast cancer. Women ≤40 years must have negative margins for invasive carcinoma when treated with BCT. Minimum surgery for an optimal cosmetic result followed by irradiation, even with microscopic positive margins for invasive carcinoma, yields excellent results with regard to local control in patients older than 40 years.