Background: Sentinel lymph node (SLN) biopsy is the preferred method for diagnosing axillary nodal involvement in breast cancer. Touch imprint cytology (TIC) and frozen section (FS) are two intraoperative techniques used to assess SLNs. Both methods have their disadvantages, and the superior technique remains uncertain.
Aim: To determine the accuracy of TIC compared to FS in identifying metastases in SLNs in preoperatively node-negative axilla.
Methods: Forty-six females with breast cancer and clinically and radiologically negative axillary lymph nodes were included in the study. For TIC, SLNs were bisected, imprinted onto clean slides, stained, and evaluated. For FS, tissue slices of the same lymph nodes were embedded in an appropriate medium and frozen to -25ºC. Tissue sections were prepared using a cryostat, stained, and evaluated.
Results: The patients' ages ranged from 30 to 71 years. There was a strong agreement between TIC and FS results (κ=0.864; p < 0.0001). Both TIC and FS findings strongly correlated with the final nodal evaluation of SLNs by paraffin section (κ=0.909; p < 0.0001 and κ=0.955; p < 0.0001, respectively). The sensitivity, specificity, positive predictive value, and negative predictive value of TIC for detecting axillary lymph node metastasis were 96.4%, 94.4%, 96.4%, and 94.4%, respectively. For FS, these values were 96.4%, 100%, 100%, and 94.7%, respectively.
Conclusion: Touch imprint cytology is a feasible, quick, and cost-effective alternative to frozen section for intraoperative evaluation of SLNs in breast cancer.