Feasibility of the use of touch imprint cytology for the assessment of axillary lymph nodes in breast cancer in the rural setting

Background Sentinel lymph node (SLN) biopsy for the assessment of axillary lymph nodes (ALN) is the gold standard in the management of breast cancer. Patients with a positive SLN will undergo an axillary clearance on a later date. Intra-operative assessment of the SLN is a valuable tool and often performed using Frozen section (FS) in certain tertiary centres. Most rural centres do not have access to this facility due to lack of resources. As patients often travel long distances for specialist treatments within the rural networks, having access to an easy-to-perform intra-operative SLN assessment tool is invaluable. Aims The aim of this study was to assess the feasibility and sensitivity of touch imprint cytology (TIC) and if it can be applied in the rural setting in assessment of SLN in invasive breast cancer. Methods 100 patients with newly diagnosed breast cancer were recruited in this cross-sectional study. The management of these patients was not altered in any manner. SLNs were assessed intra-operatively by TIC prior to being sent for formal histological (FH) analysis. We compared the intra-operative TIC assessment with the formal histopathology. This gave an indication of whether TIC assessment was comparable to alternative intra-operative SLN assessment. Results From the 100 patients selected, seventeen patients were found to be true positive, and 78 were found to be true negative. This gave TIC assessment a positive predictive value (PPV) of 0.89 and a Negative predictive value (NPV) of 0.96. The limitations of TIC were its lack of sensitivity with micrometastasis. Conclusion Our trial was limited by the small number of patients enrolled. TIC lacks the sensitivity in assessing micrometastasis and therefore we do not recommend its use in the intra-operative assessment of SLN.