Factors affecting the incidence of lymph node metastases in small cancers of the breast.

Six hundred twenty-six cases of breast cancer treated at the Mason Clinic during the period from January 1, 1977 to December 31, 1987 were retrospectively reviewed. The review included only tumors 2 cm or less in maximal diameter and sought to determine the degree of correlation between axillary lymph node metastases in each of the following: patient age, estrogen receptor status, tumor location, degree of histologic differentiation, and tumor size. Only tumor size correlated significantly with the incidence of axillary lymph node metastases (p = 0.000001). The degree of differentiation appeared to correlate with the incidence of lymph node involvement but was not statistically significant (p = 0.17). No other subset of the above factors could be identified in association with axillary lymph node metastases. Forty-five noninvasive tumors were encountered in this series; none were associated with axillary lymph node metastases. The findings of this review lend support to the importance of screening mammography in the detection of breast cancer.