Occult metastases in the axillary lymph nodes of patients with breast cancer node negative by clinical and histologic examination and conventional histology.

We examined axillary lymph nodes from 80 women with node-negative breast cancer, by immunohistochemistry, utilizing polyclonal antibodies to cytokeratins and carcino-embryonic antigen and monoclonal antibodies to cytokeratins and milk fat globulin. Occult metastatic tumor, undetectable in hematoxylin and eosin stained slides, but visible by immunohistochemistry, was detected in 23 of 80 patients (29 per cent). Occult tumor was observed in patients with invasive ductal carcinoma (21/76-28 per cent) and in individuals with invasive lobular carcinoma (2/4-50 per cent). In patients with occult metastases the primary tumors were slightly larger (mean 2.39 cm, range 1.00-5.00 cm) than those of patients whose nodes were negative for tumor cells (mean, 2.03 cm, range, 0.60-4.50 cm). Information concerning clinical outcome is available for 61 patients followed for between 1 and 7 years (mean 3.2 years). Three of 17 patients (18 per cent) who had occult tumor in the nodes developed distant metastases, all less than 3 years after initial surgery. One of the 44 patients (2 per cent) whose nodes were free of occult tumor developed distant metastases 5 years following surgery. Local recurrences in the area of the mastectomy occurred in one of 17 patients with occult nodal tumor (6 per cent), less than 1 year after surgery. Local recurrences were seen in three of 44 patients without occult metastases (7 per cent), in two patients 5 years after mastectomy and in one patient 7 years after mastectomy.