BackgroundTargeted axillary dissection (TAD) is an established method for axillary staging in patients with breast cancer after neoadjuvant chemotherapy (NAC). TAD consists of sentinel lymph node biopsy and initially pathological lymph node excision, which must be marked by a reliable marker before NAC.MethodsThe IMTAD study is a prospective multicentre trial comparing three localisation markers for lymph node localisation (clip + iodine seed, magnetic seed, carbon suspension) facilitating subsequent surgical excision in the form of TAD. The primary outcome was to prospectively compare the reliability, accuracy, and safety according to complication rate during marker implantation and detection and marker dislodgement.ResultsOne hundred eighty-nine patients were included in the study-in 135 patients clip + iodine seed was used, in 30 patients magnetic seed and in 24 patients carbon suspension. The complication rate during the marker implantation and detection were not statistically significant between individual markers (p = 0.263; p = 0.117). Marker dislodgement was reported in 4 patients with clip + iodine seed localisation (3.0%), dislodgement did not occur in other localisation methods (p = 0.999). The false-negativity of sentinel lymph node (SLN) was observed in 8 patients, the false-negativity of targeted lymph nodes (TLN) wasn & PRIME;t observed at all, the false-negativity rate (FNR) from the subcohort of ypN + patients for SLN is 9.6% and for TLN 0.0%.ConclusionThe IMTAD study indicated, that clip + iodine seed, magnetic seed and carbon suspension are statistically comparable in terms of complications during marker implantation and detection and marker dislodgement proving their safety, accuracy, and reliability in TAD. The study confirmed, that the FNR of the TLN was lower than the FNR of the SLN proving that the TLN is a better marker for axillary lymph node status after NAC.