Copyright
©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
Human epidermal growth factor receptor 2 positive rates in invasive lobular breast carcinoma: The Singapore experience
Ga-Jing Kee, Ryan Ying-Cong Tan, Sultana Rehena, Joycelyn Jie-Xin Lee, Ma Wai-Wai Zaw, Wei-Xiang Lian, Joe Yeong, Su-Ming Tan, Swee-Ho Lim, Benita Kiat-Tee Tan, Yoon-Sim Yap, Rebecca Alexandra Dent, Fuh-Yong Wong, Guek-Eng Lee
Ga-Jing Kee, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
Ryan Ying-Cong Tan, Joycelyn Jie-Xin Lee, Yoon-Sim Yap, Rebecca Alexandra Dent, Guek-Eng Lee, Division of Medical Oncology, National Cancer Centre, Singapore 169610, Singapore
Sultana Rehena, Centre for Quantitative Medicine, Duke-NUS Medical School, Singapore 169857, Singapore
Ma Wai-Wai Zaw, Department of Anaesthesiology, Singapore General Hospital, Singapore 169608, Singapore
Wei-Xiang Lian, Fuh-Yong Wong, Division of Radiation Oncology, National Cancer Centre, Singapore 169610, Singapore
Joe Yeong, Division of Pathology, Singapore General Hospital, Singapore 169608, Singapore
Su-Ming Tan, Division of Breast Surgery, Changi General Hospital, Singapore, 529889, Singapore
Su-Ming Tan, Swee-Ho Lim, Benita Kiat-Tee Tan, SingHealth Duke-NUS Breast Centre, Singapore 169610, Singapore
Swee-Ho Lim, Kandang Kerbau Breast Centre, Kandang Kerbau Women’s and Children’s Hospital, Singapore 229899, Singapore
Benita Kiat-Tee Tan, Department of Breast Surgery, Singapore General Hospital, Singapore 169608, Singapore
Author contributions: Kee GJ and Tan RYC designed research and wrote the paper; Zaw MWW, Kee GJ and Tan RYC collected data; Sultana R analyzed data; Lee JXJ, Lian WX, Yeong J, Tan SM, Lim SH, Tan BKT, Yap YS, Dent RA, Wong FH and Lee GE provided feedback on the paper.
Institutional review board statement: The study was reviewed and approved for publication by our Institutional Reviewer (IRB 2019/2419).
Informed consent statement: Informed consent was not required by the International Review Board (IRB 2019/2419) as our study did not require collection of personal/identifiable data from subjects or investigators.
Conflict-of-interest statement: All the Authors have no conflict of interest related to the manuscript.
Data sharing statement: The original anonymous dataset is available on request from the corresponding author at ryan.shea.tan.y.c@singhealth.com.sg.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Ryan Ying-Cong Tan, MBBS, MRCP, Attending Doctor, Medical Oncologist, Division of Medical Oncology, National Cancer Centre, 11 Hospital Drive, Singapore 169610, Singapore. ryan.shea.tan.y.c@singhealth.com.sg
Received: December 31, 2019
Peer-review started: December 31, 2019
First decision: March 15, 2020
Revised: April 16, 2020
Accepted: May 16, 2020
Article in press: May 16, 2020
Published online: May 24, 2020
BACKGROUND
Invasive lobular carcinomas (ILC) form 5%-10% of breast cancer and rarely show overexpression of human epidermal growth factor receptor 2 (HER2).
AIM
To describe the prevalence and prognostic factors of HER2 positive (HER2+) ILC in an Asian population.
METHODS
A retrospective review of patients with ILC seen between January 1985 and March 2018 at various SingHealth medical institutions was conducted. Demographic and clinical data were collected from medical records. We examined clinicopathological characteristics and survival in relation to HER2 status.
RESULTS
A total of 864 patients were included. Prevalence of HER2 positivity was 10.1% (87 patients). Compared with HER2 negative (HER2-) ILC, HER2+ ILC was associated with a higher proportion of estrogen receptor negative (24.4% vs 5.9%, P < 0.001), progesterone receptor negative (PR-) (40.2% vs 24%, P = 0.002) and grade 3 tumours (Grade 3, 29.0% vs 10.2%, P < 0.001). Overall survival rate was poorer in patients with HER2+ compared to HER2- ILC (56.7% vs 72.9% alive at 10 years; hazard ratio 1.87, 95% confidence interval: 1.21-2.90, P = 0.004). Based on multivariate analysis, negative prognostic factors for overall survival included HER2 positivity, PR negativity, older age, Indian ethnicity and higher tumour stage.
CONCLUSION
Prevalence of HER2+ ILC was 10.1%. HER2+ ILC was more likely to have poorer prognostic features such as estrogen receptor negative, PR- and higher tumour grade, and have a poorer survival.
Core tip: We conducted a retrospective review of 864 patients with invasive lobular breast carcinoma (ILC) and examined the clinicopathological characteristics and survival in relation to human epidermal growth factor receptor 2 (HER2) status. Interestingly, our cohort reports a higher prevalence of HER2 positive ILC (10.1%) as compared to some previous studies. HER2 positive ILC was more likely to have poorer prognostic features such as estrogen receptor negative, progesterone receptor negative and higher tumour grade, and these patients have a poorer survival compared to those with HER2 negative ILC.
