Staging nodal growth in breast cancer on a histological basis

This study describes the axillary tumour-load in 484 women with breast carcinoma with spread to one or more nodes. The aim was to relate tumour-load to nodal histology. The tumour area and that of residual lymphoid tissue was measured from standardised nodal sections. The presence/absence of tumor cells in the efferent vessels (EV) defined their nodal status as EV+ or EV-. The former has a poor prognosis. While the number of EV+ cases increased with the total tumour-load, the number of EV- cases decreased. In the EV+ there was high positive correlation between tumour-load and number of deaths from breast cancer, with a corresponding negative correlation in the EV-. Twice as many patients with EV+ nodes died of breast cancer compared to the EV- group. Investigation of 164 consecutive tumour-bearing nodes showed a similar pattern. Irrespective of EV status the area of residual lymphoid tissue remained constant. Although the lymphoid area was similar the tumour-load was twice as high in the EV+ cases. These findings stress basic biological differences in the growth of breast carcinoma in the nodes. Patients with the smallest micrometastases that are found in the afferent lymphatics of the node and the EV+ patients in which tumour cells are present in the efferent nodal vessels have a poor short-term prognosis. The patients with larger micrometastases in the nodal lymphoid tissue and also EV- patients with the next highest tumour-load are both of low prognostic risk, with the exception of the few EV- with an exceptionally high tumour-load.