Comparison of Overall Survival Between Invasive Lobular Breast Carcinoma and Invasive Ductal Breast Carcinoma: A Propensity Score Matching Study Based on SEER Database.

Weijun Pan,Fei Ji,Yi Zhang,Chuqian Lei,Kun Wang,Mei Yang,Ciqiu Yang,Liulu Zhang,Jieqing Li,Hongfei Gao,Junsheng Zhang

doi:10.3389/fonc.2020.590643

Abstract

ObjectiveInvasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) account for most breast cancers. However, the overall survival (OS) differences between ILC and IDC remain controversial. This study aimed to compare nonmetastatic ILC to IDC in terms of survival and prognostic factors for ILC.MethodsThis retrospective cohort study used data from the Surveillance, Epidemiology and End Results (SEER) Cancer Database (www.seer.cancer.gov). Women diagnosed with nonmetastatic ILC and IDC between 2006 and 2016 were included. A propensity score matching (PSM) method was used in our analysis to reduce baseline differences in clinicopathological characteristics and survival outcomes. Kaplan-Meier curves and log-rank test were used for survival analysis.ResultsCompared to IDC patients, ILC patients were diagnosed later in life with poorly differentiated and larger lesions, as well as increased expression of estrogen receptors (ERs) and/or progesterone receptors (PRs). A lower rate of radiation therapy and chemotherapy was observed in ILC. After PSM, ILC, and IDC patients exhibited similar OS (HR=1.017, p=0.409, 95% CI: 0.967–1.069). In subgroup analysis of HR-negative, AJCC stage III, N2/N3 stage patients, or those who received radiotherapy, ILC patients exhibited worse OS compared to IDC patients. Furthermore, multivariate analysis revealed a 47% survival benefit for IDC compared to ILC in HR-negative patients who received chemotherapy (HR=1.47, p=0.01, 95% CI: 1.09–1.97).ConclusionsOur results demonstrated that ILC and IDC patients had similar OS after PSM. However, ILC patients with high risk indicators had worse OS compared to IDC patients by subgroup analysis.

Highlights

Invasive lobular carcinoma (ILC) is the second most common histological subtype of invasive breast cancer and contributes to 5%–15% of all breast cancer cases [1,2,3,4]
Most of the systemic therapy decisions for ILC are derived from randomized clinical trials based on invasive ductal carcinoma (IDC), which may explain why the St Gallen International Expert Consensus guidelines and the National Comprehensive Cancer Network (NCCN) still recommend that ILC be treated with the same treatment paradigms as IDC; ILC has many unique features
The SEER tumor registry database was used to identify 1,097,908 patients diagnosed with ILC and IDC

Summary

Introduction

Invasive lobular carcinoma (ILC) is the second most common histological subtype of invasive breast cancer and contributes to 5%–15% of all breast cancer cases [1,2,3,4]. Compared to IDC, ILC has better prognosis, being almost invariably positive for hormone receptors, with low histological grade, negative for HER2 and with a generally good response to endocrine therapy [1, 3]. ILC tends to grow in a multicentric or multifocal pattern, which makes resection for negative margins difficult when performing breast-conserving surgery [7,8,9,10]. ILC is considered to be less chemo-sensitive for either adjuvant or neoadjuvant chemotherapy compared to IDC, which is thought to be mediated by molecular features, such as lowgrade and estrogen receptor (ER) positivity [1, 3, 4, 9, 14, 15]

Methods

Results

Conclusion