Ductal carcinoma in situ (DCIS) is widely accepted as a precursor of invasive ductal carcinoma (IDC). Lobular carcinoma in situ (LCIS) is considered a risk factor for invasive lobular carcinoma (ILC), and it is unclear whether LCIS is also a precursor. Therefore, it would be expected that similar risk factors predispose to both DCIS and IDC, but not necessarily LCIS and ILC. This study examined associations with risk factors using data from 3075 DCIS cases, 338 LCIS cases, and 1584 controls aged 35–60, recruited from the UK-based GLACIER and ICICLE case-control studies between 2007 and 2012. Analysis showed that breastfeeding in parous women was protective against DCIS and LCIS, which is consistent with research on invasive breast cancer (IBC). Additionally, long-term use of HRT in post-menopausal women increased the risk of DCIS and LCIS, with a stronger association in LCIS, similar to the association with ILC. Contrary to findings with IBC, parity and the number of births were not protective against DCIS or LCIS, while oral contraceptives showed an unexpected protective effect. These findings suggest both similarities and differences in risk factors for DCIS and LCIS compared to IBC and that there may be justification for increased breast surveillance in post-menopausal women taking long-term HRT.
导管原位癌（DCIS）被广泛认为是浸润性导管癌（IDC）的前期病变。小叶原位癌（LCIS）被视为浸润性小叶癌（ILC）的风险因素，但其是否同样属于前期病变尚不明确。因此可以预期，DCIS与IDC具有相似的风险因素，而LCIS与ILC之间则未必存在这种关联。本研究基于2007年至2012年间英国GLACIER和ICICLE病例对照研究的数据，纳入35-60岁的3075例DCIS患者、338例LCIS患者及1584例对照者，对相关风险因素进行了分析。研究发现，经产女性的母乳喂养对DCIS和LCIS具有保护作用，这与浸润性乳腺癌（IBC）的研究结果一致。此外，绝经后女性长期使用激素替代疗法（HRT）会增加DCIS和LCIS风险，其中与LCIS的关联性更强，这与HRT和ILC的关联模式相似。与IBC研究结果相反，产次和生育数量对DCIS或LCIS并无保护作用，而口服避孕药则显示出意外的保护效应。这些发现表明，DCIS和LCIS的风险因素与IBC既存在共性也存在差异，同时提示有必要加强对长期使用HRT的绝经后女性的乳腺监测。
DCIS and LCIS: Are the Risk Factors for Developing In Situ Breast Cancer Different?
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