[Strategies in case of metastatic sentinel lymph node in breast cancer]

Management strategy of micro or macro metastatic sentinel lymph node(s) (SLNs) in breast cancer has dramatically changed over the past ten years and the publication of five randomized trials results: ACOSOG Z0011, IBCSG 23-01, and AATRM comparing axillary lymph node dissection (ALND) versus SLNs biopsy alone; and AMAROS and OTOASOR comparing ALND versus axillary radiotherapy. Despite methodological limitations of several of these trials, notably ACOSOG Z0011, the international recommendations (ASCO, NCCN) and the expert consensus of St Gallen do not recommend the performance of a complementary ALND in case of macro or micro metastatic SLN, if all ACOSOG Z0011 inclusion criteria are met. Moreover, in the context of a mastectomy, with one or two positive SLN and a wall irradiation indication, an axillary radiotherapy can be proposed as an alternative to ALND. Additionally, ALND is also indicated in extracapsular involvement or when three or more SLNs are metastatic. This change in strategy led to a significant decrease on the number of ALNDs performed and resulted on the abandon of SLNs extemporaneous examination. In France, there are no national recommendations on axillary management in the context of SLN involvement. Moreover, a multitude of different local guidelines, led to very heterogeneous practices in our country. The next evolution on axillary management strategy will be the implementation of a SLNs procedure after neoadjuvant chemotherapy (NAC) for patients with lymph node involvement proven before NAC and for whom NAC has allowed axillary downstaging.