Clinicopathologic implications of E-cadherin reactivity in patients with lobular carcinoma in situ of the breast

BACKGROUND. The current study addressed two questions pertaining to lobular carcinoma in situ (LCIS) of the breast. First, does the risk of a subsequent carcinoma decrease over time after an LCIS biopsy and second, what is the clinical significance of E-cadherin-reactive LCIS? METHODS. Eighty-two consecutive patients with a biopsy containing LCIS only, no prior history of breast carcinoma, and follow-up information available for the period 1955-1976 were reviewed. No patients underwent a mastectomy for LCIS. Four hundred eighty-six sections were stained with E-cadherin. E-cadherin reactivity was correlated with clinicopathologic features of the LCIS and subsequent tumors. The mean number of blocks stained per case was 5.9. The mean follow-up period was 21.6 years. RESULTS. Sixteen patients (19.5%) developed 21 subsequent invasive carcinomas (9 ipsilateral, 2 contralateral, and 5 bilateral carcinomas). The 10-year and 20-year actuarial rates of developing subsequent carcinoma were 7.8% and 15.4%, respectively. Six of the 21 carcinomas (29%) developed after 20 years. Nine LCIS cases (10.9%) had focal E-cadherin reactivity. When compared with patients with nonreactive LCIS, patients with E-cadherin-reactive LCIS more frequently developed a subsequent ipsilateral carcinoma that had a ductal component (55.5% vs. 12.3%; P < 0.01). The subsequent carcinomas also developed after significantly shorter time periods (mean of 7.6 years vs. 19.6 years; P < 0.01). CONCLUSIONS. LCIS appears to confer a persistent, increased risk of subsequent breast carcinoma that does not appear to decrease over time. E-cadherin reactivity appears to identify a subset of LCIS patients with risk factors for subsequent carcinoma similar to those of patients with low-grade intraductal carcinoma. <(c)> 2001 American Cancer Society.