Mixed invasive ductal and lobular carcinoma has distinct clinical features and predicts worse prognosis when stratified by estrogen receptor status

Yi Xiao,Shen Zhao,Miao Ruan,Ding Ma,Xi-Yu Liu,Yi-Zhou Jiang,Zhi-Ming Shao

doi:10.1038/s41598-017-10789-x

Abstract

In order to investigate clinicopathological characteristics and prognosis of mixed invasive ductal and lobular carcinoma (IDC-L), 209,109 primary breast cancer patients diagnosed with invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC) or IDC-L were included. It was found that IDC-L patients had lower tumor grade and higher hormone receptor positive proportions than IDC patients. Moreover, IDC-L patients were younger and had a similar hormone receptor status compared with ILC patients. Kaplan-Meier plots showed that the breast cancer-specific survival (BCSS) of IDC-L patients was significantly better than IDC patients (P < 0.001) and tended to be better than ILC patients (P = 0.166). However, after adjusting for clinicopathological factors, survival advantage of IDC-L disappeared. Subgroup analysis indicated that IDC-L had higher hazard ratios (HRs) than IDC in grade 1, grade 2, ER-positive and ER-negative subgroups. Survival analysis in ER-positive and ER-negative subgroups showed that IDC-L predicted a worse prognosis than IDC. In conclusion, IDC-L is a distinct histological subtype compared with IDC and ILC. Lower grade and higher ER-positive proportions mainly contribute to its better prognosis. In both ER-positive and ER-negative subgroups, IDC-L predicts worse prognosis than IDC, which suggested the inadequacy of IDC-based therapy and the need of escalated therapy.

Highlights

Breast cancer is a heterogeneous entity with over 20 histological types[1,2,3]
We retrospectively investigated the clinicopathological characteristics and prognostic features of invasive ductal and lobular carcinoma (IDC-L) through a comparison of invasive ductal carcinoma (IDC)-L with IDC and invasive lobular carcinoma (ILC)
The results suggested that IDC-L has baseline characteristics that are distinct from those of IDC and ILC

Summary

Introduction

Breast cancer is a heterogeneous entity with over 20 histological types[1,2,3]. Of these distinct histological types, invasive ductal carcinoma (IDC) is the most common one, accounting for approximately 80% of all breast cancer cases, while invasive lobular carcinoma (ILC) accounts for another 5% to 15%4–6. ILC differs from IDC in many respects; for example, ILC is more multifocal and bilateral and is associated with a larger tumor size, lower histological grade, higher expression of estrogen receptor (ER) and progesterone receptor (PR), lower expression of human epidermal growth factor receptor 2 (HER2) and the loss of E-cadherin expression[7,8,9,10,11,12,13,14]. Previous studies of IDC-L are limited and contradictory because of small sample sizes, inadequate follow-up periods, a lack of adjustment for confounding factors and a lack of subgroup analyses[19,20,21,22, 25,26,27] These limitations may lead to misunderstandings and inappropriate therapies for IDC-L. We conducted a subgroup analysis to compare the survival outcome of IDC-L patients with IDC and ILC in each subgroup

Methods

Results

Conclusion