Because a positive margin is an important risk factor for decreased survival of patients with breast cancer after breast-conserving surgery (BCS), we examined the rate of positive surgical margins after BCS, determined from intraoperative frozen and preserved sections, and we assessed factors that influence the incidence of positive margins in surgical specimens. The cases of 172 patients who underwent BCS between June 1989 and March 2001 were studied. The pathologic features and positive margins were evaluated by microscopic examination of frozen and preserved sections. The grade of each positive margin was arbitrarily classified into one of four groups: i) cancer involved; ii) closed margin (<2 mm); iii) partially closed margin (>3 mm and <5 mm) and iv) free margin (>5 mm). Biomarkers were estimated by immunohistochemistry and DNA ploidy, and the relationship of clinical parameters was statistically analyzed using the χ2 test. In 59 of 172 cases (34.3%), the surgical margin was positive: horizontal in 47 cases (27.3%) and vertical in 12 cases (6.9%). The free margin was significantly correlated with positive status of estrogen and progesterone receptors and middle age (35-50 years) in the patients, while clinicopathologic factors were not correlated with positive margins in surgical specimens. Although 17 cases of cancer were found in 9 frozen specimens and 8 preserved sections, the mammographic findings showed spiculated masses in 7 of the 9 frozen specimens (77.7%) and 4 of the 8 preserved sections (50%), and microcalcification in 2 frozen specimens (22.2%) and 4 preserved sections (50%). The overexpression (2+ or 3+) of the HER-2 protein was found in 8 of the 9 frozen specimens (87.5%) and in 7 of the 8 preserved sections (88.8%). In the 11 cases with spiculated masses, extensive intraductal components (EICs) of various grades were found; the presence of EICs in a spiculated lesion was observed in 5 of the 7 frozen specimens and in all 4 of the preserved sections. The local extension of breast carcinoma cells in BCS is associated in part with the findings of spiculation and microcalcification, which are associated with EICs. The overexpression of HER-2 protein appears to play a role in EICs in positive margins, and needs to be considered for avoiding positive margins in BCS on patients with breast carcinoma.

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