Usefulness of imprint cytology and frozen section examination of the sentinel lymph node in patients with breast cancer

The accuracy of sentinel lymph node biopsy in patients with breast cancer should be both accurate and rapid, but unfortunately the false negative rate ranges between 10% and 20%. The aim of this study was to evaluate the usefulness of intraoperative imprint cytology and frozen section examination together in improving the sensitivity of sentinel lymph node procedure in patients undergoing curative surgery for primary breast cancer. Patients and Methods: A series of 86 consecutive women (median age 53 years, range 34−70) with breast cancer confirmed by fine-needle aspiration biopsy, core biopsy or open biopsy and clinically negative nodes (T1N0) underwent sentinel lymph node procedure using a combined radioisotope and blue dye method. One or more sentinel lymph node were identified in all patients. A total of 126 axillary node were processed by both intraoperative imprint cytology and frozen section examination, and the results were compared against the final pathology. Results: Permanent hematoxylin-eosin specimens reveled 44 (34.9%) metastasized axillary nodes, and confirmed breast cancer in all patients. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were the following: 88.6%, 86.4%, 86.7%, 93.9%, and 91.3% for intraoperative imprint cytology; 86.4%, 100%, 100%, 93.2%, and 95.2% for frozen section examination; 97.7%, 100%, 100%, 98.8%, 99.2% for intraoperative imprint cytology and frozen section examination together. Conclusions: Although the difference is not significant (p = NS, chisquared test) the combination of intraoperative imprint cytology and frozen section examination may improve both the sensitivity and accuracy of sentinel lymph node procedure, with a very low (<1%) false-negative rate, and should be suggested in all patients undergoing surgery for breast cancer in whom the sentinel lymph node procedure is required.