Internal mammary sentinel lymph node biopsy: abandon or persist?

Although the 2009 American Joint Committee on Cancer incorporated the internal mammary sentinel lymph node biopsy (IM-SLNB) concept, there has been little change in surgical practice patterns due to the low visualization rate of internal mammary sentinel lymph nodes with the traditional injection technique. Meanwhile, as internal mammary lymph nodes (IMLN) metastases are mostly found concomitantly with axillary lymph nodes (ALN) metastases, previous IM-SLNB clinical trials fail to evaluate the status of IMLN in patients who are really in need (only in clinically ALN negative patients). Our modified injection technique (periareolar intraparenchymal, high volume, and ultrasonographic guidance) significantly improved the visualization rate of internal mammary sentinel lymph nodes, making the routine IM-SLNB possible in daily practice. IM-SLNB could provide individual minimally invasive staging, prognosis, and decision-making for breast cancer patients, especially for patients with clinically positive ALN. Moreover, IMLN radiotherapy should be tailored and balanced between the potential benefit and toxicity, and IM-SLNB-guided IMLN radiotherapy could achieve this goal. In the era of effective adjuvant therapy, within the changing treatment approach - more systemic therapy, less loco-regional therapy - clinicians should deliberate the application of regional IMLN therapy.