Predictors of nonsentinel lymph node metastasis in breast cancer patients

Background: In order to define a future subset of breast cancer patients in whom the axilla may be staged by sentinel lymph node biopsy alone, the conditions under which nonsentinel axillary lymph node metastases occur must be delineated. Methods: A prospective database including 212 breast cancer patients who underwent sentinel lymph node biopsy followed by completion axillary dissection at our institution was reviewed. A multivariate, logistic, stepwise regression was performed to evaluate the relationship between nonsentinel lymph node metastasis and patient age, primary tumor size, presence of lymphatic invasion, use of radioisotope to identify the sentinel node and degree of metastasis in the sentinel node. Results: Tumor size greater than 2 cm, lymphatic invasion of the primary tumor, macrometastasis in the sentinel node, and use of radioisotope all positively correlated independently with metastasis in the nonsentinel lymph node (P = 0.0001, P = 0.0483, P = 0.0008, P = 0.0271, respectively). Conclusions: Predictors of nonsentinel axillary node metastasis exist and are important in defining those patients in whom a sentinel lymph node biopsy alone may not be adequate.