Intraoperative touch preparation cytology for margin assessment in breast-conservation surgery: Does it work for lobular carcinoma?

Background: Breast carcinoma is the most frequently diagnosed malignancy in women of the North America. The combination of breast-conservation surgery and radiotherapy has become a standard of treatment for most breast cancers. It is critical to obtain clear margins to minimize local recurrence. The literature suggests that intraoperative touch preparation cytology (IOTPC) can be useful in evaluation of margins. Invasive lobular carcinoma (ILC) accounts for 10% to 15% of all breast cancers. Obtaining clear margins in ILC can be more challenging. Literature shows the positive margin rate for ILC to be as high as 60%. This report describes our experience with IOTPC for margin assessment in ILC by a single surgeon at Beth Israel Medical Center. The purpose of this study is to determine whether IOTPC is reliable for ILC. Methods: A prospective review of 73 patients who underwent breast-conservation surgery with the use of IOTPC for margin assessment at Beth Israel Medical Center was performed. Pathology revealed ILC in 12 of these patients (16.4%), who are the subjects of this study. The lumpectomy specimens were oriented by the surgeon intraoperatively and were submitted fresh to pathology for cytologic assessment. IOTPC consisted of touching the corresponding margin onto the glass slide. The principle of this technique is that if cancer cells are present, they will stick to the slide, whereas fat cells will not. Six slides were prepared for each lumpectomy specimen. Air-dried samples were stained immediately by the Diff-Quik method and examined under the microscope by a cytopathologist. Results: Twelve patients with ILC underwent breast-conservation surgery with IOTPC for assessment of 72 margins. Ten patients had lobular carcinoma only, and the remaining two patients had a combination of lobular and ductal carcinoma. There was a correlation between IOTPC and final pathology in 60 of 72 margins, which accounted for 83.3% of the cases. IOTPC for assessment of margins in patients undergoing breast-conservation surgery for ILC has a sensitivity of 8.3%, specificity of 98.3%, positive predictive value of 50%, and negative predictive value of 84.3%. Conclusions: On the basis of our experience, IOTPC is of limited value for intraoperative assessment of margins for ILC.