Pathologic findings from the national surgical adjuvant breast project (protocol no. 4).V. significance of axillary nodal micro- and macrometastases

Abstract

Two-hundred seventy eight of 565 patients treated by radical mastectomy for invasive breast cancer in a prospective, randomized clinical trial exhibited axillary nodal metastases. Patients in whom the largest nodal metastasis measured ≤2 mm in its greatest diameter were regarded as having micrometastases and those in whom the lesions were ≤2 mm as having macrometastases. Contingency table analysis disclosed that the group with macrometastases had a greater likelihood that they would be clinically assessed as stage II, their primary tumors would be ≤2 cm, they would have 4 or more positive nodes, extension of the metastasis through the nodal capsule would have occurred and uninvolved nodes would exhibit a germinal center predominance pattern. Life table analyses failed to reveal any significant difference in survival between patients with micrometastases and those without nodal metastases although both of these groups exhibited significantly greater survival than patients with macrometastases. On the other hand, treatment failure rates were more comparable in patients with micrometastases to those with macrometastases rather than absent nodal involvement. Multivariate analysis revealed that these apparent effects on survival and treatment failure rates in patients with micro and macrometastases were more directly related to the number of nodes involved with metastases rather than the size of the latter. A subset of patients with micrometastases in whom the metastases measured ≥1.3 mm was identified who exhibited survival and treatment failure rates similar to those of the negative node patients. The data, although based on a relatively small sample size, suggest metastases ≥1.3 mm may exert an influence independent of number of nodes involved. The excellent prognosis of patients with these occult nodal metastases (≥1.3 mm) warrants the designation of the stage of their disease as 1 1/2. Cancer 42:2032–2038, 1978.