ABSTRACT
<p><b>OBJECTIVE</b>The aim of this study was to determine the impact of routinely performed internal mammary sentinel lymph node biopsy (IM-SLNB) on the staging and treatment, and to analyze the success rate, complications and learning curve.</p><p><b>METHODS</b>All patients with biopsy-proven breast cancer who underwent sentinel lymph node biopsy between 2012 and 2014 were included in a prospective analysis. Internal mammary sentinel lymph node biopsy (IM-SLNB) was performed in all patients with IM-SLN visualized on preoperative lymphoscintigraphy and/or detected by intraoperative gamma probe detection. The adjuvant treatment plan was adjusted according to the current guidelines.</p><p><b>RESULTS</b>In a total of 349 patients, 249 patients (71.1%) showed internal mammary drainage. IM-SLNB was performed in 153 patients with internal mammary drainage, with a success rate of IM-SLNB of 97.4% (149/153). Pleural lesion and internal mammary artery bleeding were found in 7.2% and 5.2% patients, respectively. In 8.1% of patients (12/149) the IM-SLN was tumor positive. In the group of patients who underwent IM-SLNB, lymph node staging was changed in 8.1% of patients, and IMLNs radiotherapy was guided by these results, however, systemic treatment was changed in only 0.7% of the patients.</p><p><b>CONCLUSIONS</b>IM-SLNB has a high successful rate and good safety. Identification of internal mammary metastases through IM-SLNB may provide more accurate staging and guide the tailored internal mammary radiotherapy.</p><p><b>TRIAL REGISTRATION</b>ClinicalTrials. gov, NCT01642511.</p>
