False-negative rate in the extended prospective TATTOO trial evaluating targeted axillary dissection by carbon tattooing in clinically node-positive breast cancer patients receiving neoadjuvant systemic therapy.

Purpose: In clinically node-positive breast cancer patients receiving neoadjuvant systemic therapy (NST), nodal metastases can be initially marked and then removed during surgical axillary staging. Marking methods vary significantly in terms of feasibility and cost. The purpose of the extended TATTOO trial was to report on the false-negative rate (FNR) of the low-cost method carbon tattooing.

Carbon tattooing for targeted lymph node biopsy after primary systemic therapy in breast cancer: prospective multicentre TATTOO trial.

Background: Several techniques for targeted lymph node biopsy in patients with node-positive breast cancer receiving primary systemic therapy are in use, each with their inherent advantages and disadvantages. The aim of the TATTOO trial was to evaluate the feasibility and accuracy of carbon tattooing of positive lymph nodes as a method for targeted lymph node biopsy avoiding radiation exposure, high costs, and preoperative localization procedures.

Methods: Patients with initially cT1-4c cN1-3 cM0 invasive breast cancer were included in this prospective multicentre trial.