The potential value of intraoperative imprint cytology of axillary sentinel lymph nodes in breast cancer patients.

Axillary sentinel nodes predict the node status and may allow dissection of the axilla on a selective basis. Seventy-two sentinel nodes from 60 patients identified with Patent blue and/or the high radioactivity due to the uptake of 99m-Tc-labeled colloidal albumin were bisected for hematoxylin and eosin-stained touch preparations. The sentinel nodes were submitted in toto for permanent step sections and immunostained for cytokeratins. The imprints had a sensitivity of 83 per cent, a negative predictive value of 86 per cent, and a false negative rate of 17 per cent when the cut surface histology was considered. These corresponding values were 59, 68, and 41 per cent on a patient basis when the whole sentinel node histology was considered as many micrometastases did not appear in the cut surface sampled by the imprints. Although up to two-fifths of patients with tumor cells in the sentinel lymph nodes may be undetected by the method imprint cytology is valuable in the intraoperative assessment of sentinel nodes. This series suggests that 78 per cent of the patients can be adequately selected for a one-step axillary operation on the basis of intraoperative imprints. Results may be improved if the surface sampled is appropriately large and well selected.