Factors influencing axillary node metastasis in breast cancer

The status of the axillary lymph nodes at the time of diagnosis has been accepted as one of the most important prognostic factors for the overall and disease-free survival of patients with breast cancer. The aim of our study was to determine which factors influence axillary node involvement in invasive breast cancer.

The data presented here were obtained from 344 patients who were treated for invasive breast cancer at the Department of Radiation Oncology, Uludağ University Medical College, Bursa, Turkey. Possible prognostic factors were categorized as patient related and tumor related. The Mann-Whitney U test was used for univariate analysis and logistic regression was used for multivariate analysis.

In univariate analysis, a familial cancer history (P = 0.0042), age < 40 years (P = 0.0276), higher T stage (P < 0.0000), nipple involvement (P = 0.0345), skin involvement (P = 0.0270), perineural invasion (P = 0.0231), and lymphatic vessel invasion (P < 0.0000) were correlated with increased axillary node involvement. A higher incidence of > or = 4 involved lymph nodes was associated with higher T stage (P = 0.0004), nipple involvement (P = 0.0292), presence of an extensive intraductal component (P = 0.0023), skin involvement (P = 0.0008), perineural invasion (P = 0.0523), and lymphatic vessel invasion (P < 0.0000) in univariate analysis. In multivariate analysis, age < 40 years (P = 0.0454), cancer history within the family (P = 0.0024), higher T stage (P = 0.0339), lymphatic vessel invasion (P = 0.0003), and perineural invasion (P = 0.0408) were found to be independent factors for axillary lymph node positivity. Age < 40 years (P = 0.0221), perineural invasion (P = 0.0408), and an extensive intraductal component (P = 0.0132) were associated with an increased incidence of > or = 4 involved nodes in the logistic regression analysis. In patients with breast cancer, the incidence of axillary lymph node involvement was independently influenced by age < 40 years, presence of cancer history within the family, higher T stage, lymphatic vessel invasion, and perineural invasion.

In conclusion, absence of familial cancer history, presence of lymphatic vessel invasion, higher T stage, and age below 40 years independently increased the risk of axillary node involvement. Presence of perineural invasion and lymphatic vessel invasion, age below 40, and an extensive intraductal component of more than 25% independently affected the risk of having > or = 4 nodes involved. Patients characterized by these factors may be classified into a higher risk group for nodal involvement, but more data are needed to define factors that can help in the decision-making regarding the omission of axillary treatment.