Feasibility of preoperative tattooing of percutaneously biopsied axillary lymph node: an experimental pilot study

BACKGROUND: In the last three decades, axillary lymph node dissection (ALND) has been replaced by sentinel lymph node biopsy (SLNB) in all clinically node-negative patients. However, when SLNB alone is performed in clinically node-positive patients who are rendered node-negative by neoadjuvant chemotherapy, the procedure has a high false-negative rate and other complementary procedures have been described to improve its reliability. Preoperative tattooing of the suspicious lymph node with India ink at the time of biopsy, in addition to sentinel lymph node biopsy, is a reasonable alternative. The objective of our study is to determine, in clinically node-positive patients, the feasibility of tattooing suspicious axillary lymph node at the time of percutaneous needle biopsy and its retrieval at the time of surgery. METHODS: A prospective experimental study will be conducted divided into two phases—phases I and II. In phase I, 10 patients committed to undergo upfront surgery (without neoadjuvant chemotherapy) will have a suspicious lymph node tattooed by injecting India ink at the time of core needle biopsy. All patients will undergo a SLNB, during which the axilla will be inspected to determine if the tattooed lymph node can be visualized. Routine microscopic examination will follow, and concordance between the sentinel and tattooed node will also be established. In phase II, the process will be repeated for 30 patients who undergo surgery after neoadjuvant chemotherapy. The analysis will be performed in Stata version 12. DISCUSSION: There is a need to identify and test the techniques for the down-staged axilla in post-neoadjuvant chemotherapy patients, which are not only practical and limit the number of invasive procedures necessary but are representative of the new axillary status and help limit the extent of axillary surgery without negatively impacting outcomes. We propose that, for the patient undergoing neoadjuvant chemotherapy with a biopsy-proven disease in the axilla, this could be achieved by India ink which allows marking, identification, and retrieval of the biopsied lymph node. Retrieval of this previously biopsied lymph node along with sentinel nodes, if found to be representative of the status of the remainder of the axilla, could potentially eliminate the need for routine axillary lymph node dissection and thus limit morbidity. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03939598. Retrospectively registered on 7 May 2019.