Background: Invasive lobular carcinoma (ILC), the most common special type of breast cancer (BC), has unique clinical behaviour and is different from invasive ductal carcinoma of no special type (IDC-NST). However, ILC further comprises a diverse group of tumours with distinct features. This study aims to examine the clinicopathological and prognostic features of different variants of ILC, with a particular focus on characterising aggressive subtypes. Methods: A large (n = 7140) well-characterised and histologically reviewed BC cohort with treatment and long-term follow-up data was investigated. The cohort was classified based on the WHO classification of tumours into main histological subtypes, including ILC and IDC-NST. ILCs were further classified into variants. Clinicopathological parameters and patient outcomes in terms of BC-specific survival (BCSS) and disease-free survival (DFS) were evaluated. Results: ILC constituted 11% of the cohort. The most common non-classic ILC variants were pleomorphic (pILC) and solid (sILC), constituting 19% of ILC. Compared to classic and related variants (alveolar, trabecular, papillary, and tubulolobular; cILC), pILC and sILC variants were associated with aggressive tumour characteristics. The histologic grade of ILC was an important prognostic variable. The survival patterns identified an aggressive ILC subtype encompassing pILC and high-grade sILC. These tumours, which comprised 14% of the cases, were associated with clinicopathological characteristics of poor prognosis and had high BC-specific death and recurrence rates compared not only to cILC (p< 0.001) but also to IDC-NST (p= 0.02) patients. Contrasting this, cILC patients had significantly longer BCSS and DFS than IDC-NST patients in the first 10 to 15 years of follow-up. Adjuvant chemotherapy did not improve the outcome of patients with aggressive ILC subtypes. Conclusions: pILC and high-grade sILC variants comprise an aggressive ILC subtype associated with poor prognostic characteristics and a poor response to chemotherapy. These results warrant confirmation in randomised clinical trials.
背景：浸润性小叶癌（ILC）作为乳腺癌（BC）中最常见的特殊类型，具有独特的临床行为，与无特殊类型的浸润性导管癌（IDC-NST）存在差异。然而，ILC本身还包含一组具有不同特征的异质性肿瘤。本研究旨在探讨ILC不同亚型的临床病理学特征及预后特点，特别关注侵袭性亚型的特征分析。 方法：研究基于一个大规模（n=7140）、特征明确且经过组织学复核的乳腺癌队列，该队列包含治疗及长期随访数据。根据世界卫生组织肿瘤分类标准，将队列划分为主要组织学亚型，包括ILC和IDC-NST。进一步对ILC进行亚型分类。评估了各亚型的临床病理学参数及患者结局，包括乳腺癌特异性生存期（BCSS）和无病生存期（DFS）。 结果：ILC占队列总数的11%。最常见的非经典型ILC亚型为多形性ILC（pILC）和实性ILC（sILC），占ILC病例的19%。与经典型及相关亚型（包括腺泡状、小梁状、乳头状及管状小叶型；cILC）相比，pILC和sILC亚型与侵袭性肿瘤特征相关。ILC的组织学分级是重要的预后变量。生存分析识别出一个侵袭性ILC亚型，包括pILC和高级别sILC。这些肿瘤占病例总数的14%，不仅与cILC患者相比（p<0.001），甚至与IDC-NST患者相比（p=0.02），均表现出不良预后的临床病理学特征，且具有更高的乳腺癌特异性死亡率和复发率。与此形成对比的是，在随访的前10至15年内，cILC患者的BCSS和DFS显著长于IDC-NST患者。辅助化疗未能改善侵袭性ILC亚型患者的预后。 结论：pILC和高级别sILC亚型构成了一种侵袭性ILC亚型，该亚型与不良预后特征相关，且对化疗反应不佳。这些结果需要在随机临床试验中进一步验证。
肿瘤(癌症)患者之家