Intraoperative examination of sentinel lymph nodes using scrape cytology
Background. In breast cancer, sentinel lymph node biopsy (SLNB) is widely used to assess the axilla when the nodes appear normal on palpation and ultrasonography. When the sentinel lymph nodes (SLNs) are negative, no further dissection is required. Surgical dissection or radiotherapy of the axilla is indicated for macrometastases, as well as adjuvant therapy for macrometastases and micrometastasic spread.
Aim. To determine the accuracy of scrape cytology (SC) for intraoperative examination of the SLNs.
Methods. SLNB was performed in 100 patients with early breast cancer in whom the axillary nodes appeared normal on clinical examination and ultrasonography. None of the patients with negative SLNs or SLNs with micrometastases only (N1mic, 0.2 - 2 mm) had further axillary dissection. Patients with SLNs containing macrometastases (N1, >2 mm) underwent axillary lymph node dissection. The results of intraoperative cytology were compared with the histopathological findings on examination of serial paraffin-embedded sections of the SLNs.
Results. Intraoperative SC identified SLN metastases in 20 patients: 17 had macrometastases and 3 micrometastases. Histopathological examination of the SLNs found macrometastases in 18 patients and micrometastases in 6. SC had a sensitivity of 94% and specificity of 100%
for the detection of macrometastases. For micrometastatic spread, the sensitivity and specificity were 50% and 100%, respectively.
Conclusion. SC is a rapid, sensitive technique for detection of macrometastases in the SLNs of women with breast cancer. The overall accuracy in identification of any metastatic spread (N1mic, N1) to the SLNs was 85%, rising to 94% in SLNs with macrometastases.