Options to Determine Pathological Response of Axillary Lymph Node Metastasis after Neoadjuvant Chemotherapy in Advanced Breast Cancer

Abstract

Increasing use of neoadjuvant therapy in large tumors or node positive disease in breast cancer patients or hormone negative and HER 2 overexpressing cancers often gives rise to complete clinical response, with resolution of disease in the breast and axilla. These results have raised important questions to deescalate loco-regional surgical treatment options with minimum recurrence risk and treatment related morbidity. Although there is excellent prognosis following clinical response, the primary goal of surgery still remains to confirm complete pathological response in the biopsied node that was previously positive and now clinically/radiologically negative (ycN0). Biopsied lymph nodes are often marked with a clip to allow future identification at the time of definitive surgery. The goal of lymph node surgery in oncology is that it should be accurate, hence the significance of localizing the biopsied node. This article aims to review the different options to localize the deemed positive node at the time of definitive surgery, in order to help determine pathological response after neoadjuvant therapy.

Image-Guided Localization Techniques for Metastatic Axillary Lymph Nodes in Breast Cancer; What Radiologists Should Know

“…Water absorption makes the device sonographically visible so that future localizations can be performed using ultrasound. In fact, these devices are more sonographically visible during the first weeks after their placement; then, their visibility has been demonstrated to gradually decrease in the long term up to 12–15 months, at which time they usually cannot be identified anymore [ 43 ].…”

“…Collagen-based biopsy clips have the benefit of decreasing bleeding and hematoma formation due to the hemostatic effect of collagen [ 43 ].…”

“…Moreover, a clip may sometimes lead to a reaction of the node tissue, which can be misinterpreted on pathological examination. Rare cases of allergic reactions have been described, mostly related to the presence of nickel in some titanium clips [ 43 ].…”

“…Carbon suspension-based localization of metastatic LN is a simple, radiation-free, low-cost technique that is well tolerated by the patient. Tattooing is performed at the time of biopsy and remains for up to 6–8 months after injection [ 43 ], so it has the advantage of not requiring an additional localization procedure before surgery.…”

“…Another drawback is the possibility of allergic reactions to nickel, which means that the reflector cannot be placed in patients who are allergic to this metal [ 43 ].…”