Prognostic Influence of Internal Mammary Node Drainage in Patients with Early-stage Breast Cancer

Abstract

Background: The management of internal mammary nodes (IMNs) during multidisciplinary treatment of breast cancer has been debated for the last four decades without unequivocal conclusion.

Patients and methods: We retrospectively reviewed patients with breast cancer who underwent sentinel lymph node biopsy at our center from 2008 until 2012. IMN drainage was assessed as a potential risk factor for local and distant disease recurrence.

Results: We identified 712 patients, with incidence of drainage to IMNs of 18.4%. No detrimental effect of the pattern of drainage to IMNs was found after a median follow-up of 58 months. A similar outcome was observed when drainage to IMNs was evaluated as a risk factor for patient survival. The potential risk factors for drainage to IMNs during sentinel lymph node biopsy were younger age (p=0.002) and tumor location in lower-outer, lower-inner, and upper-inner versus upper-outer quadrant (p<0.0001).

Conclusion: The drainage to IMNs is unlikely to have a detrimental effect on patient outcome.

Keywords: Breast cancer; drainage; internal mammary nodes; lymph nodes; radiotherapy.