Objective:To investigate the incidence of non-alcoholic fatty liver disease(NAFLD)in breast cancer patients and healthy individuals,and assess liver fibrosis in breast cancer patients with NAFLD.Methods:Propensity score matching(PSM)was used to match 194 breast cancer patients who were treated in the Department of Thyroid and Breast Surgery of Huai'an No.1 People's Hospital between May 2021 and December 2021,with 1 138 people who underwent physical examination during the same period.The effect of NAFLD on the risk of breast cancer was investigated by univariate and multivariate logistic regression analysis.Liver fibrosis in NAFLD patients with breast cancer was assessed by serum fibrosis markers.Differences in NAFLD status were compared in patients of different breast cancer molecular subtypes,expression of human epidermal growth factor receptor 2(HER2)and clinical staging.Results:The PSM successfully matched 164 pairs.Whether or not in menopause,the prevalence of NAFLD in the breast cancer group was significantly higher than that in the health examination group(premenopausal:12/61 vs 5/67,P=0.042;postmenopausal:27/103 vs 9/97,P=0.002).Multivariate logistic regression analysis showed that the risk of breast cancer in premenopausal NAFLD patients was 4.05 times higher than that without NAFLD[relative risk(RR)=4.05,95％confidence interval(CI):1.22-13.47,P=0.023].The same phenomenon can be observed in postmenopausal patients(RR=5.86,95％CI:2.06-16.62,P＜0.001).For patients with NAFLD,those with concurrent breast cancer have a higher risk of liver fibrosis than those without breast cancer.The incidence of NAFLD is not related to breast cancer molecular subtypes and HER2 expression,but exhibits a higher incidence in stage Ⅱ patients.Conclusion:NAFLD is closely associated with breast cancer.Patients with breast cancer have a higher proportion of NAFLD than healthy people,and NAFLD patients have an increased risk of breast cancer compared with non-NAFLD patients.Attention should be paid to the screening and management of NAFLD in breast cancer patients to prevent the incidence and progression of liver fibrosis in early stage.

Objective:To investigate the incidence of non-alcoholic fatty liver disease(NAFLD)in breast cancer patients and healthy individuals,and assess liver fibrosis in breast cancer patients with NAFLD.Methods:Propensity score matching(PSM)was used to match 194 breast cancer patients who were treated in the Department of Thyroid and Breast Surgery of Huai'an No.1 People's Hospital between May 2021 and December 2021,with 1 138 people who underwent physical examination during the same period.The effect of NAFLD on the risk of breast cancer was investigated by univariate and multivariate logistic regression analysis.Liver fibrosis in NAFLD patients with breast cancer was assessed by serum fibrosis markers.Differences in NAFLD status were compared in patients of different breast cancer molecular subtypes,expression of human epidermal growth factor receptor 2(HER2)and clinical staging.Results:The PSM successfully matched 164 pairs.Whether or not in menopause,the prevalence of NAFLD in the breast cancer group was significantly higher than that in the health examination group(premenopausal:12/61 vs 5/67,P=0.042;postmenopausal:27/103 vs 9/97,P=0.002).Multivariate logistic regression analysis showed that the risk of breast cancer in premenopausal NAFLD patients was 4.05 times higher than that without NAFLD[relative risk(RR)=4.05,95％confidence interval(CI):1.22-13.47,P=0.023].The same phenomenon can be observed in postmenopausal patients(RR=5.86,95％CI:2.06-16.62,P＜0.001).For patients with NAFLD,those with concurrent breast cancer have a higher risk of liver fibrosis than those without breast cancer.The incidence of NAFLD is not related to breast cancer molecular subtypes and HER2 expression,but exhibits a higher incidence in stage Ⅱ patients.Conclusion:NAFLD is closely associated with breast cancer.Patients with breast cancer have a higher proportion of NAFLD than healthy people,and NAFLD patients have an increased risk of breast cancer compared with non-NAFLD patients.Attention should be paid to the screening and management of NAFLD in breast cancer patients to prevent the incidence and progression of liver fibrosis in early stage.