Three Different Locations of a Sentinel Node Highlight the Importance of Performing a Sentinel Node Biopsy in Breast Cancer Recurrence

A local breast cancer recurrence or a new breast cancer in the previously treated breast is a staging challenge. Staging is important to tailor the local and the systemic treatment. Earlier treatment(s) can disrupt the primary lymphatic drainage. After the disruption, new lymphatic drainage pathways are often created. The identification of these new pathways together with their sentinel node(s) (SN) is important for retreatment. A fluorodeoxyglucose positron emission tomography-computerized tomography could be useful to identify the involved node(s), but, unfortunately, there is no evidence to support this. Ideally, in the case of a recurrence, an SN biopsy should be performed in order to identify the "new" draining lymph node(s). This new draining SN(s) can be located in unexpected places, and tumor invasion will lead to a change in the management.