Abstract
BACKGROUND: The incidence of ductal carcinoma in situ (DCIS) is increasing with the use of screening mammography, and approximately 30% of all women diagnosed with DCIS are treated by mastectomy. There is increasing use of a skin-sparing mastectomy (SSM) approach to surgically excise DCIS as this facilitates immediate breast reconstruction. The rates of locoregional recurrence (LRR) after simple mastectomy performed for pure DCIS are historically reported as 1%; however, international data suggest that LRR after SSM may be higher. METHODS: To determine our rates of LRR and compare the effect of the type of mastectomy performed, we undertook a retrospective review of all patients who underwent a mastectomy for pure DCIS at our institution between 2000 and 2010. RESULTS: In total, 199 patients underwent a mastectomy for pure DCIS (with eight local recurrences), all of which were invasive ductal carcinoma. The recurrences all occurred after SSM, which was associated with a higher 5-year LRR of 5.9% (5/102) compared with 0% in the simple mastectomy group (0/97; p = 0.012), log-rank. Univariate analysis showed the two factors that predicted the risk of recurrence were a young age at mastectomy and close or involved margins. CONCLUSIONS: These data highlight the importance of achieving clear margins, especially in young women with estrogen receptor-negative DCIS who have a higher risk of invasive recurrence. Women undergoing a mastectomy for DCIS should be counseled as to the importance of achieving clear margins and the potential increased need for further excision, post-mastectomy radiotherapy and post-reconstruction mammography in order to prevent LRR after SSM.