Synchronous bilateral breast cancer: a nationwide study on histopathology and etiology
- 21 May 2020
- journal article
- research article
- Published by Springer Science and Business Media LLC in Breast Cancer Research and Treatment
- Vol. 182 (1), 229-238
- https://doi.org/10.1007/s10549-020-05689-0
Abstract
Purpose 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. Methods 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. Results 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. Conclusion 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.Keywords
Funding Information
- Kræftens Bekæmpelse (R124-A7440-15-S2)
This publication has 35 references indexed in Scilit:
- Characteristics of Multifocal and Multicentric Breast CancersAnnals of Surgical Oncology, 2015
- Risk Assessment of Multistate Progression of Breast Tumor with State‐Dependent Genetic and Environmental CovariatesRisk Analysis, 2013
- Survival From Synchronous Bilateral Breast Cancer: The Experience of Surgeons Participating in the Breast Audit of the Society of Breast Surgeons of Australia and New ZealandAsian Pacific Journal of Cancer Prevention, 2012
- Prognosis of early-stage synchronous bilateral invasive breast cancerEuropean Journal of Surgical Oncology, 2011
- Clinical characteristics and outcomes of bilateral breast cancer in an Australian cohortThe Breast, 2011
- Survival after bilateral breast cancer: results from a population-based studyBreast Cancer Research and Treatment, 2006
- Clinicopathologic characteristics of 143 patients with synchronous bilateral invasive breast carcinomas treated in a single institutionCancer, 2004
- Bilateral synchronous breast cancer: A population-based study of characteristics, method of detection, and survivalSurgery, 2003
- Histological grade, p53, HER2 and hormone receptor status of synchronous bilateral breast carcinomaBreast Cancer, 2002
- A case-control study of unilateral and bilateral breast carcinoma patientsCancer, 2001