Is lobular carcinoma in situ as a component of breast carcinoma a risk factor for local failure after breast-conserving therapy? Results of a matched pair analysis

BACKGROUND. The goals of the current study were to compare the clinicopathologic presentations of patients with lobular carcinoma in situ (LCIS) as a component of breast carcinoma who were treated with breast conserving surgery (BCS) and radiation therapy (RT) with those of patients without LCIS as part of their primary tumor and to report rates of local control by overall cohort and specifically in patients with positive margins for LCIS and multifocal LCIS. METHODS. Sixty-four patients with Stages 0-II breast carcinoma with LCIS (LCIS-containing tumor group, LCTG) that had received BCS+RT treatment at the University of Michigan between 1989 and 2003 were identified. These patients were matched to 121 patients without LCIS (control group) in a 1:2 ratio. RESULTS. The median follow-up time was 3.9 years (range, 0.3-18.9 yrs). There were no significant differences between the two groups with regard to clinical, pathologic, or treatment-related variables or in mammographic presentation, with the exception of a higher proportion of the LCTG patients who received adjuvant hormonal therapy (P = 0.01). The rates of local control at 5 years were 100% in the LCTG group and 99.1% in the control group (P = 0.86). The presence of LCIS at the margins and the size and presence of multifocal LCIS did not alter the rate of local control. CONCLUSIONS. The extent of LCIS and its presence at the margins did not reduce the excellent rates of local control after BCS+RT. The data suggest that LCIS in the tumor specimen, even when multifocal, should not affect selection of patients for BCS and whole-breast RT.