Finding Sentinel Lymph Nodes During Mastectomy Using Indocyanine Green (INIGMA Study)

This pilot study evaluates the diagnostic value of indocyanine green (ICG) fluorescence for sentinel lymph node biopsy (SLNB) performed through the mastectomy incision in breast cancer patients. Women with clinically node-negative, invasive T1-T3 breast cancer undergoing mastectomy with SLNB at St. Antonius or Isala Hospital will be included. All patients receive standard 99mTc injection preoperatively, followed by 5 mg (2mL) ICG injection after anesthesia. The axilla will be explored for fluorescent lymph nodes via the mastectomy incision, avoiding a separate axillary incision. Primary outcome: ICG detection rate for SLN identification via the mastectomy incision. Secondary outcomes: Comparison with 99mTc detection, number of nodes identified, concordance between methods, pathology differences, detection time, and complications. ICG is safe, non-ionizing, and causes no extra discomfort or visits. Risks and burden are minimal.