Locoregional Management of Multiple Ipsilateral Breast Cancers: A Review

The incidence of preoperatively diagnosed multiple ipsilateral breast cancer (MIBC) is increasing due to improved sensitivity of screening and preoperative staging modalities including digital breast tomosynthesis (3D breast mammography) and magnetic resonance imaging (MRI). The surgical management of MIBC remains controversial. Many surgeons continue to recommend mastectomy due to high local recurrence rates in patients with MIBC undergoing breast conservation therapy reported in historic, retrospective studies. More recent retrospective studies report acceptable rates of local recurrence. Yet concerns persist due to a paucity of prospective data regarding recurrence as well as concerns for margin positivity, cosmetic outcomes and the feasibility of adequate and safe delivery of radiation following breast conserving surgery. Breast conservation has emerged as the preferred surgical strategy for eligible patients with unifocal disease. Benefits include improved quality of life, body image and sexual function and lower surgical complication rates. A recent prospective clinical trial has corroborated a large body of retrospective data confirming the safety of breast conserving therapy and adjuvant radiation in women with MIBC with good oncologic control, low rates of conversion to mastectomy and satisfactory patient-reported cosmetic outcomes. With the current rise in MIBC diagnoses, it is imperative that surgeons understand the existent evidence in order to guide shared decision-making conversations with patients diagnosed with MIBC. This comprehensive review synthesizes the best available data and offers current recommendations for management of both the primary sites of disease as well as management of the axilla in patients with MIBC.