[Two Cases of Axillary Lymph Node Recurrence of T1a Breast Cancer with Re-Treatment of Axillary Dissection and Multidisciplinary Treatment].

Regional recurrence after sentinel lymph node biopsy for breast cancer is rare, with an incidence rate of less than 1%. The rate of axillary lymph node metastasis is similar in T1a breast cancer and Tis breast cancer. In this report, we present 2 cases of axillary recurrence after sentinel lymph node biopsy for T1a breast cancer. None of the patients experienced distant recurrence, and both patients underwent axillary dissection, chemotherapy, endocrine therapy, and radiation therapy. A notable commonality between these cases was the presence of multiple invasive lesions at the time of the initial diagnosis. Currently, the extent of invasion is assessed by its maximum diameter, and the presence of multiple lesions does not influence staging. However, multiple lesions may serve as a poor prognostic marker, necessitating a judicious approach to the initial treatment. Following resection for regional recurrence, it is crucial to pursue a multidisciplinary curative approach similar to the initial management of early breast cancer with lymph node metastasis.