Predicting axillary lymph node metastases in patients with T1 infiltrating ductal carcinoma of the breast

Factors which can predict an increased risk of axillary metastases in cases of T1 breast cancer could help to identify those patients most likely to benefit from axillary surgery. This pragmatic study aimed to examine the ability of commonly reported tumour pathological features to predict axillary metastases. All cases of T1 infiltrating ductal carcinoma excised with ipsilateral axillary nodes over a 7 year period were reviewed retrospectively. Of the 639 cases, 197 (30.8%) had positive nodes. Axillary metastases were found with 66.3% of tumours showing vascular invasion but only 16.0% of those without vascular invasion. Following multivariate analysis, vascular invasion and tumour size were found to be independent predictors of positive nodes but tumour grade was not. The decision to perform axillary dissection in T1 breast cancer could be based on the presence of vascular invasion and the size of the primary tumour.