Background: Breast cancer patients with lymph node (LN) metastases at diagnosis often undergo neoadjuvant chemotherapy (NAC). Identification of a LN which regressed after NAC remains a challenge, and the current tools for marking the LN are technically cumbersome. This study examined the possibility of tattooing the LN by injecting a small amount of a commercially available carbon suspension, originally intended for marking lesions in the intestinal tract at endoscopy. The aim of the study was to evaluate the possibility of tattooing suspicious / biopsied nodes, and identifying the nodes at the time of surgery.
Methods: 0.2-0.5ml of carbon suspension was injected into one or two axillary LNs under ultrasound guidance before starting NAC. During surgery an attempt was made to identify the tattooed LN, which was removed and sent for pathological evaluation. All patients underwent a sentinel lymph node biopsy and/or axillary lymph node dissection as mandated by their clinical status.
Results: 63 patients with locally advanced breast cancer underwent tattooing of axillary LN as described. At least 1 tattooed lymph node was identified in 58 (94%) of all patients. When lymph node metastases were present, they were found in 15/18 (83%) of nodes which were both tattooed and radioactive, 12/20 (60%) of nodes which were tattooed and non-radioactive, and 13/22 (59%) of nodes which were radioactive only.
Conclusions: Ultrasound guided tattooing of involved axillary lymph nodes prior to neoadjuvant therapy is a safe and effective method of marking these nodes for future identification at the time of surgery. Identification of tattooed lymph nodes was generally easy in the majority of cases. Although the clinical impact in changing surgical decision was marginal, being able to identify and examine a lymph node which was documented to contain metastases at the time of surgery adds a degree of security to the procedure.
