The early Monash experience with targeted axillary dissection: lessons, pitfalls and practice patterns

Background and Purpose: With increasing rates of pathologic complete response (pCR) post-neoadjuvant systemic therapy, there has been an increasing focus towards de-escalating management of the node-positive axilla. Targeted axillary dissection (TAD), although comparatively novel, has become increasingly utilized at many tertiary breast centres, in select node-positive patients who revert to node-negative post neoadjuvant therapy. There remains wide variation in its practice and implementation, as well as adjuvant management post-TAD. We present the early Monash experience of implementing the TAD procedure, along with the lessons learnt, pitfalls managed and practice patterns evaluated. Methods: In this prospective database study of sequential patients undergoing TAD, 19 patients underwent the procedure. Clinicopathological characteristics of the breast tumours were evaluated, as were technical aspects of TAD, such as method of node localization and intra-operative decision making. Operative data and MDT notes were reviewed to collect information on patient data and local practice patterns. Results: Since December 2020, 19 patients have undergone TAD. 17 patients demonstrated biopsy-proven nodal metastasis, and 2 patients had morphologically abnormal lymph node(s) where biopsy was inconclusive. An average of 2.8 sentinel nodes were retrieved, and 4 cases no sentinel nodes were retrieved. The targeted node was not retrieved in 1 patient. 5 completion axillary dissections were performed, with 1 demonstrating residual disease. All TAD patients who did not have their axilla dissected were recommended at MDT to receive adjuvant radiotherapy to the axilla. Conclusions: In an era of treatment de-escalation, TAD offers significant potential for avoiding the morbidity of axillary lymph node dissection. Questions remain regarding patient selection, optimal localization techniques, and who requires an axillary dissection in the case of a positive TAD. The necessity of adjuvant radiotherapy post-TAD is unclear, but local practice patterns remain conservative.