Breast cancer Ki67, tumor size and axillary nodes relationship: it's complicated

Background

The cell proliferation labeling index Ki67 is a discussed parameter for treatment decisions in breast cancer (BC). Prior works have not settled the question whether Ki67 is independent of other tumor features. Herein, we investigated the relationship between Ki67, tumor size (T-size) and age with axillary lymph node metastases (ALNM) in early BC patients (pts).

Methods

We analyzed 1,785 pts treated for T1-T2 N0-N1 BC from 01/11/2011 to 30/09/2015 at Istituto Nazionale dei Tumori in Milan. Correlation between Ki67 and T-size was calculated by Spearman's coefficient, &rgr;. Associations of ALNM with Ki67 and other tumor characteristics were investigated by logistic regression. Fully adjusted odds ratio (OR) with 95% confidence intervals (CIs) were estimated in all cases, and separately analyzed according to T-size and age.

Results

Higher T-size was associated with higher Ki67 values in pts ≥50 years (ys) (&rgr; 0.343, p 

Conclusions

Our analysis seems to exclude significant relation between Ki67 and ALNM, while T-size and ALNM were confirmed to be highly related in all BCs but TN. Given these data it is appropriate to discuss if axillary surgery may be redundant in cases with exceptionally good prognosis and in pts with poor prognosis that will be offered systemic therapy and radiotherapy anyway. Hence BC pts aged > 50 with small tumors and low Ki67 and most TN pts represent ideal candidates for current clinical trials evaluating the potential for eliminating axillary surgery and sentinel node biopsy.

Clinical trial identification

Legal entity responsible for the study

Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy

Funding

Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy

Disclosure

All authors have declared no conflicts of interest.