Breast cancer multifocality-multicentricity and locoregional recurrance.

1029 Background: The impact of multifocality (MF) and multicentricity (MC) on locoregional (LR) control for invasive breast cancer, and the optimal local treatment strategy for these tumors, is unknown. In particular, there is disagreement in the literature regarding the use of Breast Conservation Therapy (BCT). We evaluated a large single institution cohort of MF and MC breast cancers to determine if they had inferior LR control rate when compared to their unifocal counterparts. Methods: MF and MC were defined pathologically as more than one lesion in the same quadrant and more than one lesion in separate quadrants, respectively. Patients were categorized by presence or absence of MF or MC disease and by the LR treatment modality received – BCT (n=256), mastectomy alone (n=466), or mastectomy plus post-mastectomy radiation therapy (n=184). 10 patients who underwent BCT for MC disease against physician advice were excluded. MF and MC tumors were analyzed both as a group and as separate entities. Kaplan-Me...