Imprint cytology of axillary lymph nodes as an intraoperative diagnostic tool.

AIMS: Frozen section histology of lymph nodes intraoperatively is associated with a false negative rate of twenty-five per cent. Imprint cytology is reported to have greater accuracy than frozen section. Accurate intraoperative examination of lymph nodes could help to prevent some patients from having a second axillary operation in breast cancer. This study assesses the sensitivity of imprint cytology to lymph node metastases using two different staining techniques. METHODS: Imprint cytology of 238 freshly excised axillary lymph nodes in 53 patients with stage T1-2, N0, M0 breast cancer was performed. Imprints were stained using toluidine blue dye and anti-pancytokeratin immunoglobulin to compare the two staining methods. A consultant histopathologist blinded to the routine histology results examined each set of imprints. A non-pathologist also examined each set of imprints to determine whether a technician could be used to screen slides in order to decrease the workload of the pathologist. RESULTS: Sensitivity was 82% with toluidine blue and 36.4% with anti-pancytokeratin immunoglobulin. Positive predictive values were 100% and 57% respectively for toluidine blue and anti-pancytokeratin. The false-negative rate was 18% for toluidine blue and 63.6% for anti-pancytokeratin antibody when examined by a consultant histopathologist. CONCLUSIONS: Imprint cytology using toluidine blue is as sensitive as frozen section in the detection of axillary lymph node metastases. A positive result may be acted upon with acceptable safety. Immunohistochemistry using antibody to pancytokeratin did not improve imprint sensitivity in this study. Imprint cytology could help to prevent a second operation in 80% of breast cancer patients with positive lymph nodes.

Occult lymph node metastases in patients with 'node negative' breast carcinoma treated with conservation surgery and axillary node sample and who subsequently developed axillary recurrence.

We examined axillary lymph nodes from 26 patients with node-negative breast cancer managed by axillary node sampling and no further axillary treatment, but who subsequently developed axillary recurrence after a mean follow-up of 7 years to determine the incidence of micrometastatic disease in these patients. Twenty-six matched controls with an identical length of follow-up who were node-negative on an axillary node sample, but have not developed axillary recurrence, also underwent node examination and the incidence of metastases in the two groups were compared. Lymph nodes were sectioned at two additional levels 100 microm apart. Sections at each level were stained with haematoxylin and eosin (H&E) and antibodies to PanCK and MUC1 protein. The original H&E section from each node was reviewed and additional sections from each lymph node were examined by a pathologist who was blinded to outcome. Review of the original H&E sections of the nodes revealed metastases that had been overlooked at the time of diagnosis in two (8%) patients from the recurrence group. A further two (8%) patients from the recurrence group and three (12%) from the control group had axillary nodes which contained micrometastases. Immunocytochemistry was important in identifying all micrometastases. There was no significant difference in the incidence of axillary node micrometastases between patients with and without axillary node recurrence. Although the number of cases was small, this study suggests that axillary recurrence following a negative sampling procedure is not commonly due to missed axillary node metastases.