Local recurrence in lumpectomy patients after imprint cytology margin evaluation

Background This is a follow-up study to our previously reported data on local recurrence rates in patients whose lumpectomy margins were evaluated by intraoperative imprint cytology (IICM). The purpose of this study was to compare local recurrence rates for patients whose lumpectomy margins were evaluated with IICM with local recurrence rates of those not evaluated by IICM. Methods A total of 1713 patients underwent lumpectomy treatment for breast cancer from 1988 to 2001 were prospectively entered into a computerized database and subsequently included in this study. Of the patients, 520 (group 1) had their surgery performed at an outside institution where conventional margin analysis was performed. Another 1193 (group 2) had their surgery performed at our institution where margins were evaluated by IICM. For each histologic type and for the overall sample, probabilities of recurrence with time were estimated using the method of Kaplan and Meier. Results IICM overcomes sampling error inherent in the frozen section analysis and results in a diminished incidence of overall 5-year local recurrence from 8.8% to 2.8% (P <0.0001). The recurrence rates for each respective histologic subtype are reported for both absolute recurrences and probability of recurrence with time. Conclusions IICM provides an accurate evaluation of lumpectomy margins for patients undergoing breast-conservation treatment. IICM was associated with an overall lower local recurrence rate. This series defined the utility of intraoperative imprint cytology for evaluation of margins in patients undergoing breast-conservation treatment.