Importance of the level of axillary involvement in relation to traditionalvariables in the prognosis of breast cancer

Survival in breast cancer correlates with the presence of metastatic lymph nodes, so that removal and pathological examination of the axillary nodes p rovides the most important prognostic information and basis for planning su bsequent therapy. However as the size of primary tumours at diagnosis is de creasing, the likelihood of axillary involvement is also declining, so that the indications for axillary dissection are undergoing radical revision. T o definitively establish the value of removing all three axillary lymph nod e levels (as defined by Berg) in node positive breast cancer, retrospective analysis of a large series receiving complete dissection was carried out. Consecutive breast cancer patients (n = 1003) with positive axillary nodes were analyzed: all received identical axillary treatment and the three leve ls were tagged with metal disks to facilitate recognition and pathological examination. Follow-up (mean 97 months) was exceptionally complete. The len gth of disease-free and overall survival were taken as the primary endpoint s. The variables considered in the statistical analysis were tumour size, n umber of metastatic nodes, axillary invasion by level (the three classic le vels), perilymphnodal invasion and age. By univariate analysis, overall and disease-free survival decreased significantly as tumour diameter, number o f involved lymph nodes, and involvement by axillary level increased. Multiv ariate. analysis assessing the relative importance of these variables when all were considered together found that they were all important independent predictive factors for survival. This study confirms the importance of tum our size and number of metastatic axillary nodes as predictors of outcome i n breast cancer. In addition, the level of axillary invasion as a third ind ependent factor of equal importance to the established indicators was ident ified. When axillary dissection is performed it should be complete, and all three Berg levels tagged separately, so that involvement by level can be a scertained. This provides additional important prognostic information on wh ich to base subsequent treatment decisions.