Lobular carcinoma in situ (LCIS) of the breast: is long-term outcome similar to ductal carcinoma in situ (DCIS)? Analysis of 200 cases

Lobular carcinomas in situ (LCIS) represent 1-2% of all breast cancers. Both significance and treatment remain widely debated, as well as the possible similarities with DCIS. Two hundred patients with pure LCIS were retrospectively analyzed in seven centres from 1990 to 2008. Median age was 52 years; 176 patients underwent breast-conserving surgery (BCS) and 24 mastectomy. Seventeen patients received whole breast irradiation (WBRT) after BCS and 20 hormonal treatment (15 by tamoxifen). With a 144-month median follow-up (FU), there were no local recurrences (LR) among 24 patients treated by mastectomy. With the same FU, 3 late LR out of 17 (17%) occurred in patients treated by BCS and WBRT (with no LR at 10 years). Among 159 patients treated by BCS alone, 20 developed LR (13%), but with only a 72-month FU (17.5% at 10 years). No specific LR risk factors were identified. Three patients developed metastases, two after invasive LR; 22 patients (11%) developed contralateral BC (59% invasive) and another five had second cancer. LCIS is not always an indolent disease. The long-term outcome is quite similar to most ductal carcinomas in situ (DCIS). The main problems are the accuracy of pathological definition and a clear identification of more aggressive subtypes, in order to avoid further invasive LR. BCS + WBRT should be discussed in some selected cases, and the long-term results seem comparable to DCIS.