BACKGROUND: Previous studies of patients with invasive breast cancer examined, with mixed results, tumour location as a predictor of axillary lymph node metastasis. This study assessed whether tumour location in relation to the nipple impacts the presence of axillary lymph node metastasis at the time of diagnosis. METHODS: A retrospective review was undertaken of the medical records and available imaging of 285 patients diagnosed with invasive breast cancer between January 2001 to June 2007 at Boston University Medical Center. The incidence of axillary lymph node metastasis was correlated with tumour location in relation to the posterior nipple line to control for variation in breast size. Bivariate analysis identified significant variables that were applied to a multiple logistic regression model. RESULTS: Axillary lymph node metastasis was not significantly associated with tumour proximity to the nipple. In the multivariate logistic regression analysis, known prognostic factors for axillary metastasis, such as surgical size, lymphovascular invasion, and age of diagnosis, were significant, whereas breast density, palpability, and histologic grade were no longer significant. CONCLUSIONS: Our study found that there was no evidence that correlates intramammary tumour proximity to the nipple with the presence of axillary lymph node metastasis at diagnosis. However, known prognostic factors, such as lymphovascular invasion, surgical size, and younger age at diagnosis, are strong independent predictors for axillary lymph node involvement.
BACKGROUND: Previous studies of patients with invasive breast cancer examined, with mixed results, tumour location as a predictor of axillary lymph node metastasis. This study assessed whether tumour location in relation to the nipple impacts the presence of axillary lymph node metastasis at the time of diagnosis. METHODS: A retrospective review was undertaken of the medical records and available imaging of 285 patients diagnosed with invasive breast cancer between January 2001 to June 2007 at Boston University Medical Center. The incidence of axillary lymph node metastasis was correlated with tumour location in relation to the posterior nipple line to control for variation in breast size. Bivariate analysis identified significant variables that were applied to a multiple logistic regression model. RESULTS: Axillary lymph node metastasis was not significantly associated with tumour proximity to the nipple. In the multivariate logistic regression analysis, known prognostic factors for axillary metastasis, such as surgical size, lymphovascular invasion, and age of diagnosis, were significant, whereas breast density, palpability, and histologic grade were no longer significant. CONCLUSIONS: Our study found that there was no evidence that correlates intramammary tumour proximity to the nipple with the presence of axillary lymph node metastasis at diagnosis. However, known prognostic factors, such as lymphovascular invasion, surgical size, and younger age at diagnosis, are strong independent predictors for axillary lymph node involvement.