Local recurrence after breast-conserving therapy in patients with multiple ipsilateral breast cancer

Breast-conserving therapy (BCT; lumpectomy plus radiation) is the preferred treatment for unifocal breast cancer. The multicenter phase 2 ACOSOG Z11102 trial in the United States evaluated oncologic outcomes of BCT for patients with multiple ipsilateral breast cancer (MIBC; in this study two or three ipsilateral foci). The five-year local recurrence rate was 3.1% (95% CI 1.3-6.4). Patient age, number of sites of preoperative biopsy-proven BC, ER status and HER2 status, and pathologic T and N categories were not associated with risk of local recurrence. Exploratory analysis showed that the five-year local recurrence rate was 22.6% in patients without preoperative MRI compared with 1.7% in patients with preoperative MRI. The authors conclude that BCT yields an acceptably low five-year recurrence rate for MIBC. This evidence supports BCT as a reasonable surgical option for women with two or three ipsilateral foci, particularly among patients with disease evaluated with preoperative breast MRI.