Department of Breast Surgery, Herlev and Gentofte Hospital, Copenhagen University Hospital, 2730, Herlev, Denmark.
Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.
Breast Cancer Res Treat. 2020 Jul;182(1):229-238. doi: 10.1007/s10549-020-05689-0. Epub 2020 May 21.
The aim of the present study was to describe histopathologic characteristics of synchronous bilateral breast cancer (SBBC), and by comparing SBBC to unilateral breast cancer (UBC), identify possible etiological mechanisms of SBBC.
Patients with primary SBBC (diagnosed within 4 months) and UBC diagnosed in Denmark between 1999 and 2015 were included. Detailed data on histopathology were retrieved from the Danish Breast Cancer Group database and the Danish Pathology Register. Associations between bilateral disease and the different histopathologic characteristics were evaluated by odds ratios and estimated by multinomial regression models.
1214 patients with SBBC and 59,221 with UBC were included. Patients with SBBC more often had invasive lobular carcinomas (OR 1.29; 95% CI 1.13-1.47), a clinically distinct subtype of breast cancer, than UBC patients. Further, they were older than UBC patients, more often had multifocal cancer (OR 1.13; 95% CI 1.01-1.26), and a less aggressive subtype than UBC patients. Invasive lobular carcinoma was associated with having multiple tumors in breast tissue-both in the form of bilateral disease and multifocal disease, and this association was independent of laterality. No similar pattern was observed for other tumor characteristics.
We identified two etiological mechanisms that could explain some of the occurrence of SBBC. The high proportion of less aggressive carcinomas and higher age of SBBC compared to UBC patients suggests that many are diagnosed at a subclinical stage as slow-growing tumors have a higher probability of simultaneous diagnosis. The high proportion of invasive lobular carcinoma observed in bilateral and multifocal disease, being independent of laterality, suggests that these patients have an increased propensity to malignant tumor formation in breast tissue.
本研究旨在描述双侧乳腺癌（SBBC）的组织病理学特征，并通过比较 SBBC 与单侧乳腺癌（UBC），确定 SBBC 可能的病因机制。
纳入丹麦在 1999 年至 2015 年间诊断的原发性 SBBC（在 4 个月内诊断）和 UBC 患者。从丹麦乳腺癌组数据库和丹麦病理学登记处获取有关组织病理学的详细数据。通过比值比评估双侧疾病与不同组织病理学特征之间的关联，并通过多项回归模型进行估计。
共纳入 1214 例 SBBC 患者和 59221 例 UBC 患者。与 UBC 患者相比，SBBC 患者更常患有浸润性小叶癌（OR 1.29；95%CI 1.13-1.47），这是一种临床特征明显的乳腺癌亚型。此外，SBBC 患者年龄大于 UBC 患者，更常患有多灶性癌症（OR 1.13；95%CI 1.01-1.26），且肿瘤侵袭性低于 UBC 患者。浸润性小叶癌与乳腺组织中存在多个肿瘤相关-无论是双侧疾病还是多灶性疾病，这种关联与肿瘤侧别无关。对于其他肿瘤特征，未观察到类似的模式。
我们确定了两种可能解释部分 SBBC 发生的病因机制。与 UBC 患者相比，SBBC 患者中侵袭性较低的癌比例较高且年龄较大，这表明许多患者在亚临床阶段被诊断出，因为生长缓慢的肿瘤同时诊断的可能性更高。在双侧和多灶性疾病中观察到的浸润性小叶癌比例较高，且与肿瘤侧别无关，这表明这些患者在乳腺组织中恶性肿瘤形成的倾向增加。
