Predictors for extensive nodal involvement in breast cancer patients with axillary lymph node metastases

Various prediction models have been developed to predict the risk of having no additional axillary metastases in patients with a positive sentinel lymph node biopsy (SLNB), thereby disregarding patients with a positive ultrasound-guided lymph node biopsy (UGLNB). However, in the post-Z0011 trial era it is important to identify all patients with extensive nodal involvement for whom axillary treatment might still be beneficial. Therefore, the aim of this study is to identify factors predicting extensive nodal involvement (≥3 positive nodes) in the axilla, with the emphasis on the method of axillary staging: node positivity by UGLNB versus SLNB.

All patients diagnosed with invasive breast cancer between January 2006 and December 2011 at the Máxima Medical Center were included. Univariate and multivariate logistic regression analyses were performed.

We included 302 cases, representing 301 node positive patients, of whom 177 cases had 1 or 2 positive lymph nodes and 125 cases had ≥3 positive lymph nodes. Multivariate analyses showed that a positive UGLNB (OR = 5.10; 95%CI = 2.78-9.36), lymphovascular invasion (OR = 3.60; 95%CI = 1.79-7.23) and a larger tumor size (OR = 1.03 per mm increase; 95%CI = 1.00-1.06) were significantly associated with extensive nodal involvement in patients with invasive breast cancer.

This study shows that a positive axilla, determined by UGLNB, is the most important factor for predicting further extensive nodal involvement. Hence, the role of axillary staging by ultrasound should be redefined since it might play an important role in selecting patients who may still benefit from axillary treatment.