<p>Synergistic Effect Between Full-Term Pregnancy/Breastfeeding And Familial Susceptibility On Breast Cancer Risk</p>

Abstract

BackgroundBreast cancer is the most common cancer in women worldwide, and reproductive factors and family history of malignancy are considered as high risk factors. The present study aimed to evaluate the synergistic effect of reproductive factors and family history on breast cancer.MethodA total of 1215 breast cancer patients and 1215 control participants from two medical centers were enrolled, and reproductive factor history and family cancer history information was collected. Multivariate logistic regression analyses were performed to estimate the adjusted odds ratio (OR), and synergy index (SI) was used to assess the combined effect of potential factors.ResultsCompared to the controls, a negative association between full-term pregnancy/breastfeeding and breast cancer was observed regardless of the status of family cancer history (OR: 0.675, 95% CI: 0.560–0.814 and OR: 0.631, 95% CI: 0.503–0.789 respectively) after adjustment of other confounders, while the risk effect of abortion was unproven. The synergistic effect of history of full-term pregnancy and family history of malignancy was indicated in the combined analyses with SI as 9.429 (95% CI:1.248–71.245).ConclusionFull-term pregnancy/breastfeeding were protective factors against breast cancer and synergistic additive effect was demonstrated between no full-term pregnancy/breastfeeding and a family history of malignancy on the risk of breast cancer.

Hereditary and breastfeeding factors are positively associated with the aetiology of mammary gland hyperplasia: a case–control study

“… 16 Based on these results, women with a family history of breast cancer may reduce their risk of HMG through adjustments in reproductive choices. 17 Third, since the additive model might be better to explain the biologic interaction, we also estimated the RERI, API and SI by additive models, but we did not find a statistical difference. Sample sizes may have led to a reduction in statistical power.…”

Breastfeeding and its Association with Breast Cancer: a Systematic Review of the Literature

“…In the studies conducted by Eren SK et al (2022) (19), Lopez MT et al (2017) (26), Liaw YY et al (2020) (24) and Babiker S et al (2020) (18), breastfeeding was found to have no protective effect on breast cancer incidence, but in those carried out by Lin H et al (2019) (20) and Fortner RT et al (2019) (25), breastfeeding was evaluated as a protective factor. In the study by Fortner RT et al (2019), breastfeeding was linked to a lower risk of breast cancer with negative hormone receptors.…”

“…The effect of reproductive risk factors on breast cancer incidence may be much weaker than the impact of socioeconomic factors (23). In the study carried out by Liaw et al (2020), breastfeeding was observed to have no protective effect on women with a positive family history (24), while Lin et al (2019) found that breastfeeding and full-term pregnancy exerted a protective effect, and a family history of malignancy was associated with a higher risk of breast cancer (25).…”

“…In the study by Fortner RT et al (2019), breastfeeding was linked to a lower risk of breast cancer with negative hormone receptors. Additionally, women who had given birth to three or more children and breastfed had a significantly lower risk of breast cancer with luminal A than did childless women (25). In a study by Lin H et al (2019), full-term pregnancy and breastfeeding were regarded as preventive variables because breastfeeding seemed to lower the incidence of breast cancer by almost 32% (20).…”

Temporal Trends in the Incidence and Mortality of Major Reproductive-Related Cancers in Women in Guangzhou From 2010 to 2020: A Joinpoint and Age-Period-Cohort Study

“…Reports show that the implementation rate of the 10-year plan for the development of women and children in Guangzhou (2011–2020) is 98.26%, related to the fact that by 2021, the rate of exclusive breastfeeding of infants in Guangzhou was 65.54% ( 53 ). Adherence to breastfeeding can reduce the incidence of breast cancer ( 54 ). At the same time, Guangzhou has pioneered a three-stage screening system, which has improved the sensitivity and specificity of breast cancer screening programs, better achieving “three early prevention and control” and reducing the risk of death ( 55 , 56 ).…”