Determinants of positive histologic margins and residual tumor after lumpectomy for early breast cancer: a prospective study with special reference to touch preparation cytology.

BACKGROUND AND OBJECTIVES: Removal of the entire tumor by breast-conserving surgery is important, but the determinants of adequate excision have not been established.
METHODS: A prospective study of 55 consecutive lumpectomies for early breast cancer was performed to study the correlation between touch preparation cytology and histologic margins and the determinants of positive histologic margins and residual disease after the initial excision.
RESULTS: The correlation between touch preparation cytology and histologic margins was poor: sensitivity and specificity were 37.5% and 85.1%, respectively. The histologic margins were positive in 8 cases (14.5%) and were related to the presence of intraductal carcinoma and to the large pathologic size of the index tumor. Re-excision specimen of the tumor bed (34 of 55 cases) contained residual cancer in seven cases (20.6%). Multifocal and nonpalpable index tumors predicted residual cancer. Residual disease was found in 37.5% of the cases (3 of 8) with positive and in 15.4% of the cases (4 of 26) with negative histologic margins.
CONCLUSIONS: Touch preparation cytology cannot be recommended as a method of assessing lumpectomy margins for early breast cancer. Histologic margins are misleading in predicting residual cancer in re-excision specimens. To minimize the risk of residual cancer, wide excision or mastectomy should be considered in the management of multifocal and nonpalpable tumors.