Conservative surgery for multifocal/multicentric breast cancer

Multifocal (MF) and multicentric (MC) breast cancer is regularly considered a relative contraindication for breast-conserving therapy (BCT). There are two reasons for this wide spread notion: 1. Perceived higher risk for in-breast recurrence since it is assumed that in MF/MC cancer the risk of more invasive foci in the breast is greater, and therefore radiotherapy possibly less effective. 2. Less good cosmetic outcome due to wider excisions, either segmental resection or quadrantectomy in multifocal, or multiple wide local excisions in multicentric disease. However, we concur that if optimal 'cytoreductive surgery' is achieved this will result in good local control (i.e. in-breast relapse <10% at 10 years). This can only be achieved on the basis of the right imaging, image guidance for non-palpable foci, and tumor free (invasive as well as ductal carcinoma in situ) margins after adequate pathological assessment. Surgery must then be followed by whole breast irradiation and systemic treatments as indicated by primary cancer biology. Careful planning and adaptive application of oncoplastic techniques will result in an optimal cosmetic results. The meticulous work of Roland Holland and coworkers(1) in the early 1980's on whole breast specimen showed invasive foci at more then 2 cm distance from the invasive primary cancer in more then 40% of specimen. Although multiple tumor foci may occur in up to 60% of mastectomy specimens, equivalent survival outcomes were observed in prospective trials comparing BCT and mastectomy for clinically unifocal lesions, suggesting that the majority of these foci are not, or do not become, biologically relevant or clinically significant with appropriate treatment. As diagnostic tools advance, MF and MC tumors are more commonly diagnosed. Cancers that previously would have been classified as unifocal now can be detected as MF or MC. In addition, locoregional treatment modalities have improved significantly over the past decade. More recent studies reflect these advances in diagnosis and treatment. Studies evaluated staging MRI showed that up to 19% of woman with diagnosed breast cancer harbor a second malignant ipsilateral lesion. These findings should only have consequences when additional lesions are proven cancer. Multiple enhancing lesions on MRI are in itself not an indication for a mastectomy. The Z0011 trial and the AMAROS trial demonstrated a similar phenomenon for axillary treatment; less surgery does not necessarily lead to inferior local control or survival outcomes. Recent studies supplement the growing evidence that treatment of patients with MF/MC breast cancer with BCS, radiotherapy, and adjuvant systemic therapy can result in low rates of in-breast recurrence. (C) 2015 Elsevier Ltd. All rights reserved