Intraoperative imprint cytology for breast cancer sentinel nodes: is it worth it?

Re-operative surgery is stressful for patients and is an additional burden to an already stretched public health system. Intraoperative confirmation of breast cancer metastases in sentinel lymph nodes (SLNs) provides the necessary information for the surgeon to proceed with immediate axillary dissection, avoiding the need for a second operation, its associated cost, morbidity and adjuvant treatment delays. Our challenge was to implement a technique that was rapid, inexpensive and had a negligible false positive rate. The aim of this study was to determine whether touch imprint cytology (TIC) could reduce returns to theatre without compromising patient safety and pathology department and operating theatre efficiency.

Intraoperative TIC was performed on bisected SLNs from 134 patients. Post-operatively, specimens were examined as haematoxylin and eosin-stained, paraffin-embedded 2-mm sections. Further sectioning and immunohistochemisty was performed on negative SLNs.

The sensitivity of TIC for metastases was 23.8%, the specificity was 100% and the accuracy was 76.1%. Ten patients with macrometastases and none with micrometastastes were detected intraoperatively. The sensitivity of TIC for detecting macrometastases was 34.5%, the accuracy was 78.4% and the specificity was 100%.

Ten patients avoided a subsequent surgery. The technique caused no theatre delays and the minimal cost was compensated for by the avoidance of a second procedure for a third of patients who definitively required axillary clearance. No patients had an unnecessary axillary clearance and no patients with micrometastases or isolated tumour cells were subjected to an immediate axillary clearance. It would be justifiable to continue this simple, low-cost and non-disruptive approach.