Extranodal extension on sentinel lymph node dissection: why should we treat it differently?

Area of Science:

• Oncology
• Surgical Oncology
• Breast Cancer Research

Background:

• The Z0011 trial suggested avoiding axillary lymph node dissection (ALND) in select breast cancer patients with limited sentinel lymph node (SLN) metastasis.
• Patients with extranodal extension (ENE) on SLN biopsy were excluded from this trial and typically undergo completion ALND.
• The prognostic significance of ENE detected during SLN biopsy remains unclear.

Purpose of the Study:

• To investigate the impact of ENE identified during SLN biopsy on nonsentinel lymph node (NSLN) metastasis.
• To determine the association between ENE and disease recurrence and overall mortality in breast cancer patients.

Main Methods:

• Retrospective analysis of breast cancer patients treated at a tertiary cancer center from 2005 to 2012.
• Evaluation of 655 patients who underwent SLN biopsy.
• Comparison of outcomes for patients with and without ENE on SLN biopsy, including those who had completion ALND.

Main Results:

• Of 655 patients, 8.1% had SLN metastases with ENE (SLN+ENE).
• Patients with SLN+ENE showed a trend towards higher NSLN metastasis rates compared to those with SLN metastasis without ENE (57.8% vs. 44.0%).
• ENE was significantly associated with increased disease recurrence (OR, 5.48) and overall mortality (OR, 8.16).

Conclusions:

• Extranodal extension on SLN biopsy is a significant predictor of increased axillary nodal burden.
• ENE is independently associated with a higher risk of disease recurrence and overall mortality in breast cancer patients.
• These findings suggest ENE may be a critical factor in treatment decisions regarding ALND.