Clinicopathologic subtypes and compromise of lymph nodes in patients with breast cancer

Breast cancer (BC) is currently a heterogeneous disease with variations in clinical behaviour. Classification according to subtypes has allowed progress in the individualisation of treatment. The objective of this study is to evaluate the risk of axillary node compromise in patients with BC, according to clinicopathologic subtypes. Materials and methods are a retrospective, descriptive-analytical study. All patients that had undergone surgery for invasive BC were included, with the study of sentinel lymph nodes (SLNs) at Hospital Clínico de la Pontificia Universidad Católica, between May 1999 and December 2012. The results showed 632 patients fulfilled the inclusion criteria, with the median age being 55 years (range: 28-95), and 559 (88.4%) patients presented with estrogen receptor and/or progesterone receptor positive tumours. Luminal A: 246 patients (38.9%), luminal B: 243 (38.4%), luminal not otherwise specified: 70 (11.1%) triple negative (TN): 60 (9.5%) and over expression of epidermal growth factor type 2 receptor (HER2 positive): 13 (2.1%). Luminal tumours displayed a greater risk of metastasis in the SLNs, but this difference was not statistically significant (p = 0.67). TN and HER2 positive tumours presented the greatest proportion of metastatic compromise in non-sentinel lymph nodes (non-SLNs) (57.1% and 50%, respectively). The presence of macrometastasis (MAM) in the SLN was associated with a greater risk of compromise of the non-SLN.

Luminal tumours are the most frequent and present a greater proportion of axillary lymph node compromise, without being statistically significant. TN and HER2 positive tumours tend to have a higher axillary compromise; however, this was not statistically significant in either. Only the presence of MAM in SLNs displayed a statistically significantly association in the compromise of non-SLNs.