Ipsilateral breast tumor recurrence after breast-conserving surgery: insights into biology and treatment.

Despite modern surgical and irradiation techniques, ipsilateral breast tumor recurrence (IBTR) accounts for 5-15% of all cancer recurrence in women treated with breast conservative treatment. Historically, this event has been treated definitively with salvage mastectomy and completion axillary clearance. However, many local recurrences are small and without nodal involvement at presentation. Thus, there has been an interest in performing a surgical de-escalation procedure in the breast and the axilla. The current guidelines do not provide detailed descriptions and treatment suggestions for these selected patients, resulting in inconsistent treatment strategies. Moreover, the methods to define true recurrence (TR) and new primary tumor (NP) for IBTR remain controversial. Most developed classification methods mainly rely on clinical and pathological criteria, limiting the accuracy of the discerption and causing misclassification. In this editorial, we will discuss the current trends in surgical de-escalation for patients with IBTR. Moreover, we will focus on recent IBTR innovations, highlighting molecular-integrated classification and multimodal staging methods for clinical practice and postoperative surveillance strategies.