Background: Lymphatic drainage of the breast is via subareolar and dermal lymphatics. The aim of this study was to determine whether distance of breast cancers from the skin and/or distance from the nipple impacts the likelihood of axillary nodal metastases. Methods: A retrospective review was performed of sonographically visible T1 and T2 breast cancers with breast and axillary surgery performed at Mayo Clinic, Rochester, MN. Distance of tumor from the nipple was reviewed. Ultrasounds were reviewed to measure the distance of tumor from the skin. Results: Data were collected on 233 eligible T1 or T2 breast cancers, of which 177 (76%) were node negative and 56 (24%) were node positive. On multivariable analysis, tumor stage and lymphovascular invasion, as well as decreasing distance of the tumor from the nipple and decreasing distance of the tumor from the skin, were significantly associated with axillary lymph node positivity. Each 1-cm decrease in the distance of the tumor from the nipple was associated with a 23% increased likelihood of positive lymph nodes (odds ratio 1.23; P =.003). Each 1-mm decrease in the distance of the tumor from the skin was associated with a 15% increased likelihood of positive lymph nodes (odds ratio 1.15; P =.003). Conclusion: T1 and T2 breast cancers located closer to the skin and those located closer to the nipple have a higher incidence of metastases to axillary lymph nodes. Distance from the skin and distance from the nipple should be considered when estimating a patient's likelihood of axillary nodal positivity.
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