The impact of lifestyle and reproductive factors on the risk of a second new primary cancer in the contralateral breast: a systematic review and meta-analysis.
Cancer Causes Control
; 31(5): 403-416, 2020 May.
Article
in En
| MEDLINE
| ID: mdl-32130573
ABSTRACT
PURPOSE:
The risk of being diagnosed with contralateral breast cancer (CBC) is an important health issue among breast cancer survivors. There is an increasing interest in the effect of lifestyle and reproductive factors on CBC risk, since these factors may partly be modifiable. We performed a systematic review and meta-analysis and aimed to evaluate the impact of lifestyle and reproductive factors on CBC risk in population-based breast cancer studies.METHODS:
The PubMed electronic database was searched up to 2nd November 2019, for relevant publications. Of the included studies, a meta-analysis per lifestyle or reproductive factor was performed.RESULTS:
Thirteen out of 784 publications were used for the meta-analysis. Body mass index (≥ 25 vs. < 25 kg/m2; RR = 1.22; 95% CI 1.01-1.47) was associated with increased CBC risk. The estimates for alcohol use (ever vs. never; RR = 1.15; 95% CI 1.02-1.31) and age at primiparity (≥ 25 vs. < 25 years; RR = 1.06; 95% CI 1.02-1.10) also showed an association with increased CBC risk. For parity (≥ 4 vs. nulliparous; RR = 0.56; 95% CI 0.42-0.76) and age at menopause (< 45 vs ≥ 45 years; RR = 0.79; 95% CI 0.67-0.93), results from two studies suggested a decreased CBC risk. We observed no association between CBC and smoking, age at menarche, oral contraceptive use, gravidity, breastfeeding, or menopausal status. Overall, the number of studies per risk factor was limited (n = 2-5).CONCLUSIONS:
BMI is a modifiable risk factor for CBC. Data on the effect of other modifiable lifestyle and reproductive factors are limited. For better counseling of patients on lifestyle effects, more studies are urgently needed.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Breast Neoplasms
/
Neoplasms, Second Primary
/
Life Style
Type of study:
Etiology_studies
/
Risk_factors_studies
/
Systematic_reviews
Limits:
Adult
/
Female
/
Humans
/
Middle aged
/
Pregnancy
Language:
En
Journal:
Cancer Causes Control
Journal subject:
EPIDEMIOLOGIA
/
NEOPLASIAS
Year:
2020
Type:
Article
Affiliation country:
Netherlands