Touch imprint cytology of axillary lymph nodes after neoadjuvant chemotherapy in patients with breast carcinoma

BACKGROUND Neoadjuvant chemotherapy (NC) reportedly downstages axilla in approximately one-third of patients with locally advanced breast carcinoma (LABC). Postchemotherapy axillary lymph node status is an important prognostic factor. In the current study, the authors evaluated the reliability of touch imprint cytology (TIC) in detecting axillary lymph node metastasis after NC and identified chemotherapy-induced changes that may influence this assessment. METHODS Thirty-three patients with LABC were studied. Seventeen patients had received chemotherapy before surgery (NC group) and 16 patients had not (non-NC group). Touch imprints were made from either the largest axillary lymph node (in 13 patients from the NC group and 16 patients from the non-NC) or the sentinel lymph node (in 4 patients from the NC group). Imprints from the NC group were evaluated for metastasis and were correlated with histopathology. Touch imprints from both groups were compared for cellularity, tumor load, necrosis/degeneration, and histiocytes. RESULTS Cytologic evaluation for metastasis was 100% concordant with histopathology in all 17 patients from the NC group (9 positive results [53%] and 8 negative results [47%]). The presence of few tumor cells in sparsely cellular imprints that exhibited necrosis (two patients) and the presence of only degenerating/necrotic tumor cells (two patients) were two cytologic patterns unique to post-NC imprints that may have influenced their accurate assessment. CONCLUSIONS TIC was found to be reliable for the intraoperative evaluation of axillary lymph node metastasis after NC. However, a careful examination is warranted in sparsely cellular imprints, because there is the possibility of overlooking a small group of tumor cells. To the authors' knowledge, the significance of finding extensive necrosis in axillary lymph nodes after NC is not known and may be investigated. Cancer (Cancer Cytopathol) 2003;99:346–51. © 2003 American Cancer Society.