Systemic Therapy of Locoregional Recurrence of Breast Cancer

Abstract

Historically, locoregional recurrence (LRR) of breast cancer comprised the recurrence of breast cancer following mastectomy occurring in the skin of the chest wall, the surgical scar, the axilla, or in other regional lymph nodes such as the ipsilateral supraclavicular, infraclavicular, and internal mammary nodes. With the establishment of breast-conserving surgery (BCS) as an effective alternative to mastectomy, ipsilateral breast tumor recurrence (IBTR) was added as a potential site of LRR in patients undergoing BCS. While LRR sometimes presents concurrently with distant metastatic disease, it most often occurs as isolated locoregional recurrences (ILRRs). ILRRs are associated with a high risk of subsequent distant metastatic disease and ultimately death from metastatic breast cancer. Risks are higher with ILRR following mastectomy than with ILRR following BCS. A review of the literature reporting prognosis after LRR demonstrated an overall 5-year disease-free survival (DFS) of 30% and 5-year overall survival (OS) of 35% in patients initially treated with mastectomy. In patients treated with BCS, the overall 5-year DFS following LRR was 59%, and the 5-year OS was 68%. The National Surgical Adjuvant Breast and Bowel Project (NSABP) evaluated prognosis following LRR as a first event across 5 large adjuvant trials conducted in women with node-positive breast cancer treated with BCS and defined the risks following IBTR and following LRR in other sites (oLRR). The 10-year cumulative incidences of IBTR and oLRR were 8.7% and 6.0%, respectively. The 5-year distant DFS following IBTR and oLRR was 51.4% and 18.8%, respectively, indicating a better prognosis in