Thoracoscopic Internal Mammary Lymph Node Dissection: A Video Demonstration

Internal mammary lymph node (IMN) metastasis in breast cancer is a well-established prognostic factor of similar importance to axillary lymph node status. Although randomized controlled trials in the 1970s failed to show a survival benefit of IMN dissection during extended radical mastectomy, they did demonstrate diminished survival of patients with IMN metastasis.1,2 The 2011 National Comprehensive Cancer Network Clinical Practice Guidelines recommend radiotherapy to the IMN chain that is clinically or pathologically positive. However, the direct contribution of IMN irradiation to improved survival is still controversial, while it may contribute to the increased risk of relevant cardiac mortality.3‐5

Thoracoscopic internal mammary node dissection is a novel minimally invasive technique to assess and treat IMN metastasis. It ensures that the whole IMN chain is excised for histological evaluation, and therefore, no further irradiation of these regional nodes is needed.

This procedure is indicated in the following instances: operable invasive breast cancer; all medial or central tumors; lateral tumors with involved axillary lymph nodes; primary internal mammary lymphatic drainage detected by lymphoscintigraphy; and no contraindications to thoracoscopic surgery, including the inability to tolerate single-lung ventilation and extensive pleural adhesion.

Thoracoscopic internal mammary node dissection is a feasible procedure designed to provide simultaneous assessment and management of IMN metastasis. However, a larger study cohort with long-term follow-up is required to verify its safety and clinical significance.