Lobular carcinoma in situ increases the risk of local recurrence in selected patients with stages I and II breast carcinoma treated with conservativesurgery and radiation

BACKGROUND. Lobular carcinoma in situ (LCIS) is a known risk factor for the development of invasive breast carcinoma, However, little is known regardi ng the impact of LC IS in association with an invasive carcinoma on the ris k of an ipsilateral breast tumor recurrence (IBTR) in patients who are trea ted with conservative surgery (CS) and radiation therapy (RT). The purpose of this study was to er;amine the influence of LCIS on the local recurrence rate in patients with early stage breast carcinoma after breast-conserving therapy, METHODS. Between 1979 and 1995, 1274 patients with Stage I or Stage II inva sive breast carcinoma were treated with CS and RT, The median follow-up tim e was 6.3 veers. RESULTS. LCIS was present in 65 of 1274 patients (5%) in the study populati on. LCIS was more likely to be associated with an invasive lobular; carcino ma (30 of 59 patients; 51%) than with invasive ductal carcinoma (26 of 1125 patients; 2%). Ipsilateral breast tumor recurrence (IBTR) occurred in 57 o f 1209 patients (5%) without LCIS compared with 10 of 65 patients (15%) wit h LCIS (P = 0.001). The 10-year cumulative incidence rate of IBTR was 6% in women without LCIS compared with 29% in women with LCIS (P = 0.0003). In b oth groups, the majority of recurrences were invasive. The 10-year cumulati ve incidence rate of IBTR in patients who received tamoxifen was 8% when LC IS was present compared with 6% when LCIS was absent (P = 0.46). Subsets of patients in which the presence of LCIS was associated with an increased ri sk of breast recurrence included tumor size < 2 cm (T1), age < 50 years, in vasive ductal carcinoma, negative lymph node status, and the absence of any adjuvant systemic treatment (chemotherapy or hormonal therapy) (P < 0.001) , LCIS margin status, invasive lobular carcinoma histology, T2 tumor size, and positive axillary lymph nodes were not associated with an increased ris k of breast recurrence in these women. CONCLUSIONS, The authors conclude that the presence of LCIS significantly i n creases the risk of an ipsilateral breast tumor recurrence in certain sub sets of patients who are treated with breast-conserving therapy The risk of local recurrence appears to be modified by the use of tamoxifen. Fur ther studies are needed to address this issue. (C) 2001 American Cancer Society.