Touch preparations for the intraoperative evaluation of sentinel lymph nodes after neoadjuvant therapy have high false-negative rates in patients with breast cancer

Context.-The use of a touch preparation for intraoperative sentinel lymph node diagnosis has become a preferred method of many pathologists because of its reported high sensitivity and rapid turnaround time. However, after neoadjuvant chemotherapy many lymph nodes have significant treatment-related changes that may affect the diagnostic accuracy of the intraoperative evaluation. Objective.-To determine the accuracy of touch preparation for the intraoperative diagnosis of metastatic breast carcinoma in the neoadjuvant setting. Design.-We reviewed retrospectively the results of intraoperative evaluations for 148 different sentinel lymph nodes from 63 patients who had undergone neoadjuvant chemotherapy for invasive breast cancer at our institution. The intraoperative touch preparation results were compared with the final pathology reports in conjunction with relevant clinical data. Results.-Use of touch preparation for the evaluation of sentinel lymph nodes intraoperatively after neoadjuvant therapy was associated with a low sensitivity of 38.6% (95% confidence interval [CI], 24.4-54.5) but high specificity of 100% (95% CI, 96.5-100). There was no difference in sensitivity rates between cytopathologists and noncytopathologists in this cohort (P = .40). Patients with invasive lobular carcinoma and those who had a clinically positive axilla before the initiation of neoadjuvant therapy were the most likely to have a false-negative result at surgery. Conclusions.-Intraoperative touch preparations should not be used alone for the evaluation of sentinel lymph nodes in the setting of neoadjuvant therapy for breast cancer because of low overall sensitivity.