Intra-operative touch preparation cytology; does it have a role in re-excision lumpectomy?

OBJECTIVE: Breast carcinoma is the most frequently diagnosed malignancy in women of North America. The combination of breast conservation surgery and radiotherapy has become a standard of treatment for the majority of breast cancers. It is critical to obtain clear margins to minimize local recurrence. However, avoiding multiple re-excisions for margin clearance helps optimize cosmetic results in patients undergoing breast conservation surgery. Intra-operative touch preparation cytology (IOTPC) may decrease the need for multiple re-excisions and thereby improve cosmesis. The literature suggests that IOTPC can be useful in evaluation of margins. Klimberg et al. evaluated the touch preparation technique prospectively in 428 patients undergoing breast biopsy for undiagnosed breast masses. Margin evaluation was correct in 100% of the lesions and was used to re-excise the margins when touch prep results were positive. They reported a diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 100% for the touch prep technique. To the best of our knowledge, there has been no published data on the role of IOTPC for evaluation of margins in re-excision cases. This report describes our experience with IOTPC for margin assessment for re-excision partial mastectomy at Beth Israel Medical Center (BIMC). The purpose of this study is to determine whether IOTPC is reliable for evaluating margins in patients undergoing re-excision for involved or close margins.

METHODS: A prospective study of 30 patients, who have undergone re-excision partial mastectomy for involved or close margins after breast conservation surgery with the use of IOTPC for margin assessment at BIMC was performed. The re-excision lumpectomy specimens were oriented by the surgeon intra-operatively and were submitted fresh to pathology for cytologic assessment. The touch prep method 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, while fat cells will not. A slide was prepared for each re-excision specimen. Air-dried samples were stained immediately using the Diff-Quik method and examined under the microscope by a cytopathologist.

RESULTS: Thirty patients underwent re-excision lumpectomy for involved or close margins with touch preparation cytology for assessment of 68 margins. Twenty-six patients had invasive ductal carcinoma and/or ductal carcinoma in situ, three patients had invasive lobular carcinoma and the remaining one patient had a combination of invasive lobular and ductal carcinoma. There was a correlation between touch prep cytology and final pathology in 56/68 margins, which accounts for 82.4% of the cases.

CONCLUSION: Intra-operative touch preparation cytology for assessment of margins in patients undergoing re-excision lumpectomy for involved or close margins has a sensitivity of 75%, specificity of 82.8%, positive predictive value of 21.4%, and negative predictive value of 98.2%. This high negative predictive value and a single false negative margin are quite significant. Therefore, based on our experience, IOTPC can be a useful tool for intra-operative assessment of margins for patients undergoing re-excision partial mastectomy.