Parity and risk of developing breast cancer according to tumor subtype: A systematic review and meta-analysis.
Breast cancer subtypes
Meta-analysis
Parity
Systematic review
Journal
Cancer epidemiology
ISSN: 1877-783X
Titre abrégé: Cancer Epidemiol
Pays: Netherlands
ID NLM: 101508793
Informations de publication
Date de publication:
12 2021
12 2021
Historique:
received:
20
06
2021
revised:
08
10
2021
accepted:
12
10
2021
pubmed:
28
10
2021
medline:
15
12
2021
entrez:
27
10
2021
Statut:
ppublish
Résumé
Clinical breast cancer subtypes are categorized basing on the expression of hormone receptors and overexpression of the human epidermal growth factor receptor 2 (HER2). It is still unclear whether parity impact the risk of different breast cancer subtypes. We searched eight mainstream databases for published epidemiologic studies that assessed the relationship between parity and risk of breast cancer subtypes up to January 12, 2021. Parity number were unified into nulliparity and ever parity. The random-effects or fixed-effect models were used to calculate the pooled odds ratios (ORs) and 95% confidence intervals (CIs) among different subtypes. Restricted cubic spline analysis with four knots was applied to determine the relationship of parity number and risk of breast cancer subtypes. We pooled sixteen case-control and four cohort studies, and performed an analysis including 7795 luminal A, 3576 luminal B, 1794 HER2-overexpressing, and 5192 triple-negative breast cancer cases among 1135131 participants. The combined ORs for ever parity versus nulliparity indicated a 34% reduction in luminal A risk (OR=0.66, 95% CI: 0.56-0.78), and a 29% reduction in luminal B risk (OR=0.71, 95% CI: 0.63-0.81), there was no significant association in HER2-overexpressing or TNBC risk. In the dose-response analysis, we observed a potentially non-linear and gradually increasing protective relationship between the number of parity and luminal breast cancer risk. The effect of parity on breast cancer seems to vary among breast tumor subtypes, and it plays a protective role in luminal breast cancer.
Sections du résumé
BACKGROUND
Clinical breast cancer subtypes are categorized basing on the expression of hormone receptors and overexpression of the human epidermal growth factor receptor 2 (HER2). It is still unclear whether parity impact the risk of different breast cancer subtypes.
METHODS
We searched eight mainstream databases for published epidemiologic studies that assessed the relationship between parity and risk of breast cancer subtypes up to January 12, 2021. Parity number were unified into nulliparity and ever parity. The random-effects or fixed-effect models were used to calculate the pooled odds ratios (ORs) and 95% confidence intervals (CIs) among different subtypes. Restricted cubic spline analysis with four knots was applied to determine the relationship of parity number and risk of breast cancer subtypes.
RESULTS
We pooled sixteen case-control and four cohort studies, and performed an analysis including 7795 luminal A, 3576 luminal B, 1794 HER2-overexpressing, and 5192 triple-negative breast cancer cases among 1135131 participants. The combined ORs for ever parity versus nulliparity indicated a 34% reduction in luminal A risk (OR=0.66, 95% CI: 0.56-0.78), and a 29% reduction in luminal B risk (OR=0.71, 95% CI: 0.63-0.81), there was no significant association in HER2-overexpressing or TNBC risk. In the dose-response analysis, we observed a potentially non-linear and gradually increasing protective relationship between the number of parity and luminal breast cancer risk.
CONCLUSIONS
The effect of parity on breast cancer seems to vary among breast tumor subtypes, and it plays a protective role in luminal breast cancer.
Identifiants
pubmed: 34706325
pii: S1877-7821(21)00167-3
doi: 10.1016/j.canep.2021.102050
pii:
doi:
Substances chimiques
Biomarkers, Tumor
0
Receptors, Estrogen
0
Receptors, Progesterone
0
Receptor, ErbB-2
EC 2.7.10.1
Types de publication
Journal Article
Meta-Analysis
Research Support, Non-U.S. Gov't
Review
Systematic Review
Langues
eng
Sous-ensembles de citation
IM
Pagination
102050Informations de copyright
Copyright © 2021 Elsevier Ltd. All rights reserved.