Prognostic Significance of Lobular Carcinoma In-Situ (LCIS) Diagnosed Alongside Invasive Breast Cancer

PURPOSE: Women with lobular carcinoma in-situ (LCIS) have an increased risk for developing breast cancer (BC) compared with the general population. However, little is known about the clinical implication of diagnosing LCIS concurrently with an invasive breast cancer. We aimed to define the rate of LCIS diagnosed concurrently with an invasive breast cancer and investigate the risk of contralateral breast cancer (CBC) during survivorship care. MATERIALS AND METHODS: A single center retrospective review over 6 years identified women with stage I-III BC who underwent lumpectomy or unilateral mastectomy. Patients with or without concurrent LCIS were compared using Chi-squared analyses to assess for differences in clinicopathologic factors and risk of future CBC (including invasive and in-situ disease). RESULTS: Of 1808 patients, 16.6% (n = 301) had LCIS concurrent with their index breast cancer. Patients with LCIS had a higher rate of subsequent CBC development than those without LCIS (3.3% versus 1.0%, P = .004). The risk ratio for patients with LCIS developing subsequent CBC compared with those without LCIS was 3.3 (95% confidence interval [CI]: 1.5-7.3). CONCLUSIONS: Patients with LCIS diagnosed concurrently with their index breast cancer at surgery are at higher risk for subsequent CBC than those without LCIS. The evidence from this study suggest that it may be appropriate for women with LCIS diagnosed alongside an index breast cancer to consider on-going high-risk screening during survivorship care.