Contralateral lymph node recurrence in breast cancer: Regional event rather than distant metastatic disease. A systematic review of the literature

Aims: After treatment for breast cancer, some patients experience a contralateral lymph node recurrence (CLNR). Traditionally, contralateral nodes are considered a distant site. However, aberrant lymph drainage after previous surgery is common. This might indicate that CLNR is a regional event. This study aimed to review the literature to determine prognosis after CLNR. Methods: PubMed was searched up until July 2014. Articles on CLNR with or without ipsilateral breast tumour recurrence (IBTR), and repeat sentinel node (SN) studies reporting on positive contralateral nodes were included. Exclusion criteria were synchronous contralateral breast cancer and synchronous distant events. Results: 24 articles were included, describing 48 patients. Of these 48, 26 patients had an isolated CLNR, 7 IBTR and clinically detected CLNR, and 15 IBTR with a positive contralateral repeat SN. Isolated CLNR occurred earlier (45.9 months) than IBTR with CLNR (126.6 months, p <0.001) or with a positive contralateral repeat SN (217.2, p = 0.02). Surgical treatment was described for 38 patients, and consisted of axillary lymph node dissection for 34 (89.5%). Information on adjuvant therapy was available for 27 patients, 21(77.8%) received chemotherapy. Follow-up information after CLNR was available for 23 patients (47.9%). Mean follow-up was 50.3 months. Overall survival and disease-free survival were 82.6% [95% CI 67.1-98.1] and 65.2% [45.7-84.7] respectively at last follow-up. Conclusions: Although observed in a small population, the survival of CLNR is not comparable to distant disease. Most patients received locoregional and systemic treatment suggesting a curative approach. This indicates that CLNR should be regarded as a regional event.