Distance Between the Tumour and Nipple as a Predictor of Axillary Lymph Node Involvement in Breast Cancer

Purpose: The possibility of axillary node metastasis via the lymphatics might be related to a cancer's location within the breast. Previous studies of this topic had small sample sizes, inaccuracies because of subjective differences, and the inability to depict the entire three-dimensional structure of the breast. Here, we aimed to improve upon these existing drawbacks by retrospectively analysing whether tumour location (quadrants) and tumour-nipple distance can predict axillary node positivity. Patients and Methods: We identified 961 patients with invasive breast cancer between January 2000 and April 2016. The tumour-nipple distance was objectively measured intraoperatively and clinicopathological information was extracted from hospital database. The distance was measured radially from the nipple to the epicentre rather than the edge of tumour to obviate confounders resulting from tumour size variations. Results: A total of 847 breast cancers (839 patients) met the eligibility criteria and were included in the statistical analysis. The tumour-nipple distance was smaller in node-positive patients (n = 307; 2.76 +/- 2.07 cm) than in node-negative patients (n = 297; 3.41 +/- 2.18 cm) (p < 0.001). Tumour-nipple distance was an independent predictor of axillary involvement on logistic regression analysis. However, no statistically significant relationship was detected between node positivity and breast quadrant tumour location. Conclusion: Tumour-nipple distance can be used to predict axillary lymph node metastasis and assist in surgical decision-making and therapy planning. However, exploratory studies are required to increase our understanding of the mechanism.