Breast Cancer In Korean Women Research Articles

Hormone replacement therapy and breast cancer incidence in Korean women

ObjectivesAfter the 2002 Women's Health Initiative (WHI) study, the global use of menopausal hormone therapy (MHT) declined, and despite subsequent studies indicating a low risk of breast cancer, concerns about MHT usage persist. We examined the relationship between changes in MHT use and changes in the incidence of breast cancer from 2002 to 2020 in South Korea. Study designThis study used tumor registry information from 2002 to 2020 from the Korean Statistical Information Service and analyzed the incidence rate of invasive breast cancer in women, who were divided into two age groups: <50 and >50 years. The numbers of MHT prescriptions in Korea between 2002 and 2020 was determined from pharmacy data. ResultsThe incidence of breast cancer per 100,000 women in South Korea increased from 34.3 in 2002 to 96.4 in 2020. Breast cancer incidence rates increased annually in both groups of women (those aged under and over 50 years), with no significant difference between the two (p = 0.614). Prescriptions for estrogen therapy (ET) in 2020 were 52.7 % lower than those in 2002. Prescriptions for estrogen-progesterone therapy (EPT) decreased by 27.9 % over the same period. Conversely, tibolone prescriptions, which had initially decreased by 25.4 % in 2004, subsequently showed a steady increase and were 93.6 % higher in 2020 than in 2002. ConclusionThe incidence of breast cancer increased annually in Korean women of all ages; however, the use of ET and EPT for MHT has declined since 2002, particularly the use of EPT after 2010. MHT, especially EPT, did not significantly increase the incidence of breast cancer in Korean women.

Comparison of cardiovascular disease risk in women with and without breast cancer: secondary data analysis with the 2014–2018 korean national health and nutrition examination survey

BackgroundAging breast cancer survivors may be at an elevated risk of cardiovascular disease (CVD), but little is known about CVD risk assessment and breast cancer in Korean women. We hypothesized that Korean breast cancer survivors would have higher risks of future CVD within the next 10 years (i.e., Framingham Risk Score [FRS]) than women without cancer.Objectives(1) To compare FRS-based CVD risks in women with and without breast cancer based on propensity score matching; and (2) To explore adiposity-related measures in relation to FRS in Korean women with breast cancer.MethodsUsing the cross-sectional data from the 2014–2018 Korean National Health and National Survey (KNHANES), we identified 136 women with breast cancer aged 30–74 years who had no other cancer and no CVD. The comparison group of 544 women with no cancer were selected by 1:4 nearest-neighbor propensity score matching based on breast cancer diagnosis. CVD risk was assessed by FRS based on multiple traditional risk factors (e.g., cholesterol, blood pressure, diabetes, and smoking). Adiposity was measured by physical examination, including body mass index (BMI) and waist-to-height ratio (WHtR). Physical activity and health behaviors were assessed by self-reports.ResultsWomen with breast cancer (mean age of 57 years) had similar FRS levels at a low-risk category (< 10%) to women with no cancer (4.9% vs. 5.5%). Breast cancer survivors (mean 8.5 survival years) presented at significantly lower levels of total cholesterol, BMI, and WHtR (all p values < 0.05) than their counterpart. Within the breast cancer group, WHtR ≥ 0.5 was associated with higher FRS, compared to WHtR < 0.5. FRS was not different by survival < 5 years or ≥ 5 years after breast cancer diagnosis.ConclusionsFRS-based CVD risks were not different in Korean, mostly postmenopausal, women by breast cancer status. Whereas breast cancer survivors had even lower levels of lipid and adiposity measures than women without cancer, those values indicating borderline cardiometabolic risk suggest continued screening and management efforts for these aging women. Future studies are needed to examine longitudinal trajectories of CVD risk factors and CVD outcomes among Korean breast cancer survivors.

Development of a Breast Cancer Risk Prediction Model Incorporating Polygenic Risk Scores and Nongenetic Risk Factors for Korean Women.

To develop a breast cancer prediction model for Korean women using published polygenic risk scores (PRS) combined with nongenetic risk factors (NGRF). Thirteen PRS models generated from single or multiple combinations of the Asian and European PRSs were evaluated among 20,434 Korean women. The AUC and increase in OR per SD were compared for each PRS. The PRSs with the highest predictive power were combined with NGRFs; then, an integrated prediction model was established using the Individualized Coherent Absolute Risk Estimation (iCARE) tool. The absolute breast cancer risk was stratified for 18,142 women with available follow-up data. PRS38_ASN+PRS190_EB, a combination of Asian and European PRSs, had the highest AUC (0.621) among PRSs, with an OR per SD increase of 1.45 (95% confidence interval: 1.31-1.61). Compared with the average risk group (35%-65%), women in the top 5% had a 2.5-fold higher risk of breast cancer. Incorporating NGRFs yielded a modest increase in the AUC of women ages >50 years. For PRS38_ASN+PRS190_EB+NGRF, the average absolute risk was 5.06%. The lifetime absolute risk at age 80 years for women in the top 5% was 9.93%, whereas that of women in the lowest 5% was 2.22%. Women at higher risks were more sensitive to NGRF incorporation. Combined Asian and European PRSs were predictive of breast cancer in Korean women. Our findings support the use of these models for personalized screening and prevention of breast cancer. Our study provides insights into genetic susceptibility and NGRFs for predicting breast cancer in Korean women.

Characteristics and chronologically changing patterns of late-onset breast cancer in Korean women of age ≥ 70 years: A hospital based-registry study

BackgroundWomen from Asian and western countries have vastly different ages of onset of breast cancer, with the disease tending to occur at an older age in the West. Through an investigation of the patterns of old-onset breast cancer (OBC) in Korean women, we aimed to identify the characteristics of Korean OBC and evaluate whether these patterns are changing in relation to increasing westernization.MethodsThis study retrospectively evaluated 102,379 patients who underwent surgical treatment of primary breast cancer between January 1, 2000 and December 31, 2013 in Korea. We used hospital -based breast cancer registry and analyzed data from these patients using multiple linear regression analysis to compare the characteristics and chronologically changing patterns between OBC (70 years of age or older) and non-OBC (40–69 years of age) patients in Korea.ResultsA total of 6% of the 102,379 patients had OBC. Overall, OBC had more favorable biological features, such as a higher incidence of luminal A subtype, than did non-OBC, except for a higher incidence rate of triple-negative breast cancer (TNBC). However, OBC also presented with a higher overall disease stage, including higher T and M stages. Although the incidence rates of both OBC and non-OBC have increased overtime, the relative proportion of OBC patients has slightly increased, whereas that of non-OBC has slightly decreased. The increase in the incidence of both OBC and non-OBC was primarily due to the luminal A subtype.ConclusionsBased on a hospital-based registry, overall, Korean OBC had favorable biological features but showed a higher rate of TNBC and advanced cancer stages. The incidence trend of breast cancer in Korea is slowly shifting toward an older age at onset, largely due to the luminal A subtype. Our results may provide novel insights into OBC in Asia, and aid in the development of optimal management of the disease in Asia.Trial registrationRetrospectively registered.

Polygenic risk scores for prediction of breast cancer in Korean women.

Polygenic risk scores (PRSs) for breast cancer, developed using European and Asian genome-wide association studies (GWAS), have been shown to have good discrimination in Asian women. However, prospective calibration of absolute risk prediction models, based on a PRS or PRS combined with lifestyle, clinical and environmental factors, in Asian women is limited. We consider several PRSs trained using European and/or Asian GWAS. For each PRS, we evaluate the discrimination and calibration of three absolute risk models among 41 031 women from the Korean Cancer Prevention Study (KCPS)-II Biobank: (i) a model using incidence, mortality and risk factor distributions (reference inputs) among US women and European relative risks; (ii) a recalibrated model, using Korean reference but European relative risks; and (iii) a fully Korean-based model using Korean reference and relative risk estimates from KCPS. All Asian and European PRS improved discrimination over lifestyle, clinical and environmental (Qx) factors in Korean women. US-based absolute risk models overestimated the risks for women aged ≥50 years, and this overestimation was larger for models that only included PRS (expected-to-observed ratio E/O = 1.2 for women <50, E/O = 2.7 for women ≥50). Recalibrated and Korean-based risk models had better calibration in the large, although the risk in the highest decile was consistently overestimated. Absolute risk projections suggest that risk-reducing lifestyle changes would lead to larger absolute risk reductions among women at higher PRS. Absolute risk models incorporating PRS trained in European and Asian GWAS and population-appropriate average age-specific incidences may be useful for risk-stratified interventions in Korean women.

Consecutive gain and loss in body weight and waist circumference with risk of subsequent breast cancer in Korean women.

This study investigated the association between longitudinal changes in weight and waist circumference and breast cancer risk according to menopausal status. This retrospective cohort study used data from the population-based Korean National Health Insurance Service (NHI) database. The study population included women aged ≥40 years who consecutively underwent three biennial breast cancer screenings between 2009-2014 and were followed up until 2020. The percentage changes in weight and waist circumference during the three screenings were calculated and categorized into five groups based on the level of increase or decrease in these two factors. Hazard ratios (HRs) and 95% confidence intervals (95% CI) for breast cancer risk were calculated and adjusted for other factors. Of 691,253 premenopausal and 1,519,211 postmenopausal women, 9485 and 12,553 breast cancer cases were identified, respectively, during a median 6.9 follow-up years. Postmenopausal women with two consecutive weight gains had an increased risk of breast cancer risk (HR = 1.11, 95% CI = 1.01 to 1.22); meanwhile, consecutive weight loss was associated with a decreased risk (HR = 0.84, 95% CI = 0.76 to 0.93). Single time and continuous decreases in waist circumference were associated with a decreased risk (HR = 0.91, 95% CI = 0.85 to 0.98, and HR = 0.84, 95% CI = 0.76-0.93), while single time and continuous increases were associated with an increased risk (HR = 1.08, 95% CI = 1.01 to 1.15, and HR = 1.13, 95% CI = 1.04 to 1.22). Single weight gain was associated with the increased breast cancer risk in premenopausal women (HR = 1.07, 95% CI = 1.01 1.13). Our findings suggest a dose-response relationship between weight, waist circumference change, and the risk of future breast cancer.

Do lifestyle factors influence risk of breast cancer recurrence in Korean women?: a cross-sectional survey.

PurposeThis study aimed to investigate the influencing factors of breast cancer recurrence by comparing the risk factors and lifestyle patterns related to breast cancer in Korean women with and without recurrence.MethodsThis cross-sectional survey comprised 241 Korean women diagnosed with breast cancer who had received follow-up treatment. Participants were recruited from a university hospital in Seoul and an online social media platform for breast cancer patients. Data were collected either via online or a paper survey, using a structured questionnaire that included general and disease-related characteristics and lifestyle behaviors. Data were analyzed using descriptive statistics, univariate analysis, and logistic regression.ResultsRecurrence of breast cancer was influenced by four factors; childbirth experience, consumption of green/yellow vegetables, drinking behavior, and recovery from fatigue after sleep.Prevalence of recurrent breast cancer was associated with no childbirth experience (OR=2.29, p=.010), fewer green/yellow vegetables (OR=0.71, p=.008), drinking behavior (OR=0.24, p=.001), and a lower level of recovery from fatigue after sleep (OR=0.51, p<.001).ConclusionAside from having experienced childbirth, this study identified several modifiable factors that influence breast cancer recurrence. Increasing green/yellow vegetable intake, alleviating fatigue, and reducing alcohol intake are important. Intervention strategies in clinical research and practice can be applied to address risk factors and reduce the prevalence of recurrent breast cancer.

Abstract 5903: Polygenic risk scores for prediction of breast cancer in Korean women

Abstract Background: Polygenic risk scores (PRS) developed in large European GWAS have been shown to perform well in Asian women relative to PRS developed in smaller Asian studies. However, prospective validation of absolute risk prediction models combining lifestyle and PRS in Asian women is limited. We evaluate the calibration of four PRS developed using Asian or European training samples; two PRS were restricted to genome-wide significant SNPs (GRS-11ASN, GRS-136EUR) and two included sub-genome-wide significant SNPs (PRS-42ASN, PRS-209EUR). Methods: For each PRS, we compared discrimination (area under the curve [AUC]) and calibration (expected-to-observed ratio [E/O]) of three absolute risk models among 41,031 women from the Korean Cancer Prevention Study-II Biobank: (i) a model using incidence, mortality, and risk factor distributions (reference inputs) among U.S. women and European relative risks; (ii) a recalibrated model, using Korean reference but European relative risks; and (iii) a fully Korean-based model using Korean reference and relative risk estimates from KCPS. Results: All Asian and European PRS improved risk prediction for breast cancer in Korean women (Qx: AUC=0.65, Qx+PRS-42ASN: AUC=0.68, Qx+PRS-209EUR: AUC=0.69 in Korean-based model for age less than 50). We found that the U.S.-based absolute risk models overestimated the risks for women age ≥50 years (PRS-42ASN: E/O=1.93, 95% CI=1.69, 2.19, PRS-209EUR: E/O = 1.92, 95% CI=1.69, 2.19). Our absolute risk projections suggest that risk-reducing lifestyle changes would lead to larger absolute risk reductions among women at higher PRS. Conclusions: Incorporation of PRS previously developed in Asian and European-ancestry populations can improve discrimination in Korean women. Our finding suggests that PRS may be useful for prioritizing individuals for targeted intervention on their lifestyle such as alcohol intake and obesity. Larger Asian training samples should improve PRS discrimination among Korean women. Further studies are needed to evaluate the value of incorporating additional information on factors into a model in ancestrally diverse populations. Citation Format: Yon Ho Jee, Weang-Kee Ho, Sohee Park, Douglas Easton, Soo-Hwang Teo, Keum Ji Jung, Peter Kraft. Polygenic risk scores for prediction of breast cancer in Korean women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5903.

Evaluation of the Value of Multiplex MicroRNA Analysis as a Breast Cancer Screening in Korean Women under 50 Years of Age with a High Proportion of Dense Breasts.

This study was conducted to confirm the performance of the microRNA (miRNA) biomarker combination as a new breast cancer screening method in Korean women under the age of 50 with a high percentage of dense breasts. To determine the classification performance of a set of miRNA biomarkers (miR-1246, 202, 21, and 219B) useful for breast cancer screening, we determined whether there was a significant difference between the breast cancer and healthy control groups through box plots and the Mann–Whitney U-test, which was further examined in detail by age group. To verify the classification performance of the 4 miRNA biomarker set, 4 classification methods (logistic regression, random forest, XGBoost, and generalized linear model plus random forest) were applied, and 10-fold cross-validation was used as a validation method to improve performance stability. We confirmed that the best breast cancer detection performance was achievable in patients under 50 years of age when the set of 4 miRNAs were used. Under the age of 50, the 4 miRNA biomarkers showed the highest performance with a sensitivity of 85.29%, specificity of 93.33%, and area under the curve (AUC) of 0.961. Examining the results of 4 miRNA biomarkers was found to be an effective strategy for diagnosing breast cancer in Korean women under 50 years of age with dense breasts, and hence has the potential as a new breast cancer screening tool. Further validation in an appropriate screening population with large-scale clinical trials is required.

Microbiota of Breast Tissue and Its Potential Association with Regional Recurrence of Breast Cancer in Korean Women.

Recent studies have reported dysbiosis of the microbiome in breast tissue collected from patients with breast cancer and the association between the microbiota and disease progression. However, the role of the microbiota in breast tissue remains unclear, possibly due to the complexity of breast cancer and various factors, including racial and geographical differences, influencing microbiota in breast tissue. Here, to determine the potential role of microbiota in breast tumor tissue, we analyzed 141 tissue samples based on three different tissue types (tumor, adjacent normal, and lymph node tissues) from the same patients with breast cancer in Korea. The microbiota was not simply distinguishable based on tissue types. However, the microbiota could be divided into two cluster types, even within the same tissue type, and the clinicopathologic factors were differently correlated in the two cluster types. Risk of regional recurrence was also significantly different between the microbiota cluster types (p = 0.014). In predicted function analysis, the pentose and glucuronate interconversions were significantly different between the cluster types (q < 0.001), and Enterococcus was the main genus contributing to these differences (q < 0.01). Results showed that the microbiota of breast tissue could interact with the host and influence the risk of regional recurrence. Although further studies would be recommended to validate our results, this study could expand our understanding on the breast tissue microbiota, and the results might be applied to develop novel prediction methods and treatments for patients with breast cancer.

The Relationship Between Breast Density Change During Menopause and the Risk of Breast Cancer in Korean Women.

The aim of this study was to investigate the relationship between changes in breast density during menopause and breast cancer risk. This study was a retrospective, longitudinal cohort study for women over 30 years of age who had undergone breast mammography serially at baseline and postmenopause during regular health checkups at Samsung Medical Center. None of the participants had been diagnosed with breast cancer at baseline. Mammographic breast density was measured using the American College of Radiology Breast Imaging Reporting and Data System. During 18,615 person-years of follow-up (median follow-up 4.8 years; interquartile range 2.8-7.5 years), 45 participants were diagnosed with breast cancer. The prevalence of dense breasts was higher in those who were younger, underweight, had low parity or using contraceptives. The cumulative incidence of breast cancer increased 4 years after menopause in participants, and the consistently extremely dense group had a significantly higher cumulative incidence (CI) of breast cancer compared with other groups [CI of extremely dense vs. others (incidence rate per 100,000 person-years): 375 vs. 203, P < 0.01]. Korean women whose breast density was extremely dense before menopause and who maintained this density after menopause were at two-fold greater risk of breast cancer. Extremely dense breast density that is maintained persistently from premenopause to postmenopause increases risk of breast cancer two fold in Korean women. Therefore, women having risk factors should receive mammography frequently and if persistently extremely dense breast had been detected, additional modalities of BC screening could be considered.

Enhanced Susceptibility to Breast Cancer in Korean Women With Elevated Serum Gamma-Glutamyltransferase Levels: A Nationwide Population-Based Cohort Study.

BackgroundThe incidence of breast cancer has been gradually increasing in Korea. Recently, the elevated level of serum gamma-glutamyltransferase (GGT) has emerged to be associated with the development and progression of some malignancies. This study aimed to determine the effect of serum GGT levels on the risk of developing breast cancer in Korean women.MethodsWe used National Health Insurance Service Health Checkup data to examine the association between serum GGT levels and breast cancer development in Korean women. Women aged 40 years or older who participated in the Korean National Health Screening Examination between January 2009 and December 2009 and who did not develop any cancer within 1-year post examination were included in this analysis (n = 3,109,506). Cox proportional hazard regression analysis was conducted to calculate hazard ratios (HRs) with 95% confidence intervals (CIs).ResultsOverall, an elevated serum GGT level was associated with the increased risk of developing breast cancer; compared to the Q1 group, the Q4 group showed a significantly increased breast cancer risk (HR: 1.120,95% CI: 1.08–1.162). Such a relationship was stronger in post-menopausal women than pre-menopausal women (HR: 1.173, 95% CI: 1.107–1.243; HR: 1.070, 95% CI:1.019–1.124). Women with a high GGT level (Q4) were also at an increased risk of developing carcinoma in situ (CIS) (HR: 1.114, 95% CI: 1.04–1.192). In post-menopausal women, the Q4 group also exhibited higher CIS risk (HR: 1.266, 95% CI: 1.132–1.416). However, no significant difference in the risk of developing CIS was observed between the Q1 and Q4 groups in pre-menopausal women. Further analysis revealed that obese, post-menopausal women with a high GGT level (Q4) were associated with an increased risk of developing breast cancer (HR: 1.214, 95% CI: 1.125–1.31) and CIS (HR: 1.348, 95% CI: 1.159–1.569).ConclusionsOur study results demonstrate that increased serum GGT level is a risk factor for developing breast cancer. The post-menopausal women group with obesity and elevated serum GGT level showed the highest incidence of breast cancer. Thus, serum GGT concentration could be a novel and potential risk factor for breast cancer. Further validation in different ethnic groups would be warranted.

A Nationwide Study on the Incidence of Breast Cancer in Korean Women with Osteoporosis Receiving Raloxifene Treatment.

PurposeRaloxifene is a selective estrogen receptor modulator (SERM), and raloxifene treatment for osteoporosis is reimbursable under the Korean National Health Insurance. Evidence suggests that SERMs use reduces the risk of breast cancer in Asian population. Herein, we retrospectively investigated the protective effect of raloxifene on breast cancer rates in Korean population.MethodsUsing the Health Insurance Review and Assessment Service database, we selected women with osteoporosis aged 50 years and above. Patients treated for at least 2 years with raloxifene were assigned to the user group, whereas the remaining patients were assigned to the non-user group. The effect on breast cancer risk was assessed using the Cox proportional-hazards model with a time-dependent covariate to adjust for immortal time bias.ResultsA total of 322,870 women who were registered between 2010 and 2011 were included. The user group comprised 0.7% (n = 2,307) of the total population. The mean age was 65.7 ± 8.0 years and 67.2 ± 8.6 years in the user and non-user groups, respectively (p < 0.001). There was no difference in the previous use of estrogen replacement between the 2 groups (p = 0.087). The incidence of breast cancer per 1,000 person-years was 0.49 (n = 8) and 0.68 (n = 1,714) in the user and non-user groups, respectively (hazard ratio [HR], 0.63, 95% confidence interval [CI], 0.32–1.27). HR decreased with increase in the treatment duration, but this change was not statistically significant (HR, 1.00, 95% CI, 0.32–3.11 in 2–3 years; HR, 0.63, 95% CI, 0.20–1.94 in 3–4 years; and HR, 0.41, 95% CI, 0.10–1.65 in 4–5 years).ConclusionLong-term treatment with raloxifene in women with osteoporosis was not significantly associated with a reduction in breast cancer rates. However, further investigation is required for a conclusive proof.

Abstract LB-279: Multi-grain rice diet decreases risk of breast cancer in Korean women: Results from the Health Examinees study

Abstract Background: Several studies have examined associations between breast cancer risk and individual foods and nutrients. Most studies have evaluated risks associated with individual foods and nutrients, rather than measures of whole-diet. The objective of this study was to investigate the association between dietary patterns and the risk for breast cancer. Methods: A total of 93,306 women aged 40-69 years were enrolled in the prospective cohort study in the Health Examinees-Gem (HEXA-G) study between 2004 and 2013. Information on cancer diagnosis in the eligible cohort was retrieved from the Korea Central Cancer Registry through 31 December 2014. Dietary patterns were identified using factor analysis of data from a 106-item validated food frequency questionnaire. We conducted a multivariable Cox regression model to obtain the hazard ratio (HR) and 95% confidence interval (CI) for the risk of breast cancer according to the dietary pattern scores. Results: A total of 359 incident cases of breast cancer occurred over an average follow-up period of 6.3 years. Using a factor analysis, we identified three major dietary patterns, which explained 23.9% of the total variance, based on the daily total food intake (g/day) from 37 food groups: the Vegetables and seaweed pattern (greater intake of yellow-green and other vegetables, seaweed, lean fish, and shellfish), the Flour and meat pattern (greater intake of bread, pizza and hamburger, red meat, and poultry), the White rice and salt fermented fish pattern (greater intake of white rice and salt fermented fish). We found that the women who had higher white rice and salt fermented fish pattern scores tend to have higher risk of breast cancer. Multivariate HR (95% CI) comparing the highest with the lowest quintiles of White rice and salt fermented fish pattern scores was 1.35 (1.00, 1.84) (p for trend = 0.0384). Other two dietary patterns, the Vegetables and seaweed pattern and the Flour and meat pattern, showed no significant association with the breast cancer risk for women. Conclusion: The White rice and salt fermented fish pattern was associated with a increased risk of breast cancer, but further investigation involving subgroup analysis is warranted. Citation Format: Woo-Kyoung Shin, Hwi-Won Lee, Aesun Shin, Jong-koo Lee, Daehee Kang. Multi-grain rice diet decreases risk of breast cancer in Korean women: Results from the Health Examinees study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-279.

Multi-Grain Rice Diet Decreases Risk of Breast Cancer in Korean Women: Results from the Health Examinees Study.

Although a number of studies explain the association between dietary patterns, which take into account that foods are eaten in combination, and breast cancer risk, the findings are inconsistent. We examined the association between dietary patterns and multi-grain rice intake, and the risk of breast cancer in a large-scale prospective cohort study in Korean women. A total of 93,306 women aged 40–69 years from the Health Examinees-Gem (HEXA-G) study (2004 and 2013) were included. We obtained Information on cancer diagnosis via linkage to the Korea Central Cancer Registry. Factor analysis was conducted to obtain dietary patterns, and Cox proportional models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (95% CI) for breast cancer risk. For 494,490 person-years, 359 new cases of breast cancer occurred. We identified three major dietary patterns, that explained 23.9% of the total variance based on daily total food intake (g/day) from 37 food groups: the meat dietary pattern (higher intake of bread and red meat), the white rice dietary pattern (higher intake of white rice and lower intake of multi-grain rice), and the other pattern. Women who had higher white rice dietary pattern scores had a 35% higher risk of breast cancer, than did women with lower white rice dietary pattern scores (multivariable HR 1.35; 95% CI 1.00–1.84 for the highest vs. lowest quartile of the white rice dietary pattern scores, p for trend = 0.0384). We found that women who consumed three or more servings of multi-grain rice per day had 33% lower risk of breast cancer than did those who consumed one or less multi-grain rice serving per day among women under 50 years of age (multivariable HR 0.67; 95% CI 0.45–0.99, p for trend = 0.0204). Our study suggests that a multi-grain rice diet may be associated with lower risk of breast cancer in Korean women.

Serum Levels and Glycosylation Changes of Alpha-1-Acid Glycoprotein According to Severity of Breast Cancer in Korean Women.

Elevated serum levels of alpha-1-acid glycoprotein (AGP) are known to be associated with several types of cancer. In addition, some reports have indicated that changes in glycosylation of AGP are associated with cancer progression. However, changes in AGP levels of serum and changes in glycosylation of AGPs in breast cancer have not been specifically studied. In the present study, serum AGP levels in benign (BN) cancer and breast cancer stage I (BC I), BC IIA, BC IIB, and BC III in Korean women were measured using an enzyme-linked immunosorbent assay (ELISA). AGP was purified from individual sera by hot phenol extraction and then subjected to AGP glycosylation analysis. Three types of AGP glycosylation (fucosylation, high-mannose-type and sialylation) were detected using enzyme-linked lectin assays (ELLAs). Serum AGP levels were higher in BC I, BC IIA, BC IIB, and BC III, than in the BN group, and the level in BC I and BC IIA was high enough to be distinguished from BN. Meanwhile, terminal fucosylation and high-mannose-type glycans appeared to be lowest in BC I. The glycosylation levels of BC I provide sensitivity and specificity that make BC I clearly distinguishable from BC IIA, BC IIB, and BC III as well as BN. Therefore, determination of serum AGP or AGP glycosylation level could be useful for detecting the early stages of breast cancer.

Milk Consumption Decreases Risk for Breast Cancer in Korean Women under 50 Years of Age: Results from the Health Examinees Study.

Epidemiologic studies regarding breast cancer risk related to milk consumption remain controversial. The aim of this study was to evaluate the association between milk consumption and the risk for breast cancer. A total of 93,306 participants, aged 40–69 years, were included in the prospective cohort study in the Health Examinees-Gem (HEXA-G) study between 2004 and 2013. Dietary intake was assessed using a validated food frequency questionnaire. Information on cancer diagnosis in the eligible cohort was retrieved from the Korea Central Cancer Registry through 31 December 2014. The Cox proportional hazards model was used to estimate multivariate hazard ratios (HRs) and 95% confidence intervals (CIs). A total of 359 breast cancer cases were observed over a median follow-up period of 6.3 years. Milk consumption was not associated with decreased risk for breast cancer in the total population (p for trend = 0.0687). In women under 50 years of age, however, milk consumption was inversely associated with breast cancer risk. In the comparison between highest (≥1 serving/day) and lowest (<1 serving/week) intake categories of milk, the multivariate HR (95% CI) was 0.58 (0.35–0.97, p for trend = 0.0195)) among women under 50 years of age. In conclusion, our findings show that milk consumption in Korean women aged 50 or younger is associated with a decreased risk for breast cancer, when compared to those who never or rarely consumed milk. Further studies need to be conducted to assess this relationship and confirm these results.

Outcomes of Pregnancy after Breast Cancer in Korean Women: A Large Cohort Study

PurposeThe purpose of this study was to determine the rate and outcomes of pregnancies subsequent to breast cancer in Korea, and the effect of such pregnancies on the prognosis of women who survived breast cancer and subsequently conceived.Materials and MethodsWe followed a total of 31,761 Korean women 45 years of age or younger who were treated for primary breast cancer from 2002 to 2010. We also included follow-up surveys that were conducted through December 2011. We identified recurrence and mortality from breast cancer using data linked to the Korea National Health Insurance database. We used propensity score matching of the study cohort to analyze the risks of recurrence and mortality from breast cancer depending on pregnancy.ResultsWithin our sample, 992 women (3.1%) became pregnant after receiving treatment for breast cancer. Of those, 622 (67.5%) successfully delivered; the remaining 370 (32.5%) failed to deliver. After propensity score matching, we found that the women who became pregnant after breast cancer did not have a different risk of recurrence (hazard ratio [HR], 0.503; 95% confidence interval [CI], 0.434 to 0.584) and death (HR, 0.520; 95% CI, 0.397 to 0.681), compared with those who did not conceive after breast cancer treatment.ConclusionOur study is the first to report outcomes for Korean women who survived breast cancer and subsequently conceived. Women who survived breast cancer and subsequently became pregnant did not show a poorer survival outcome, compared with those who did not become pregnant.

Dietary Inflammatory Index and Risk of Breast Cancer Based on Hormone Receptor Status: A Case-Control Study in Korea.

Breast cancer is the most common cancer in women globally, and the risk of developing breast cancer is associated with inflammation. The present study aimed to examine the association between the Dietary Inflammatory Index (DII®) and breast cancer in Korean women and investigate whether the tumor’s hormone receptor status affects this association. In this case-control study, we enrolled 364 breast cancer patients and 364 age-matched controls. DII scores were calculated from dietary intake evaluated by a 106-item food frequency questionnaire. The DII score was significantly higher in cases than in controls. After adjusting for potential confounders, the odds ratio (OR) of breast cancer was higher in the highest DII tertile (OR = 3.68, 95% confidence interval (CI): 2.34–5.80, p for trend < 0.0001) than in the lowest tertile. We found that higher DII scores were related to an increased risk of breast cancer for estrogen receptor (ER)+/progesterone receptor (PR)+ tumors regardless of menopausal status (OR = 2.59, 95% CI: 1.37–4.88 in the highest DII category, p for trend = 0.01 for premenopausal women; OR = 11.00, 95% CI: 2.93–41.30 in the highest DII category, p for trend = 0.0004 for postmenopausal women), but not for ER−/PR− status. Our results suggested that the DII scores are positively associated with breast cancer risk in Korean women and that this relationship is more robust in ER+/PR+ tumors.

Night-shift work and risk of breast cancer in Korean women.

PurposeThis study evaluated the association between night-shift work (NSW) and breast cancer risk as well as subtypes of breast cancer in Korean women.Patients and methodsThe study population included 1721 female breast cancer cases and 1721 female controls matched by age. The subtypes of breast cancer were determined based on estrogen, progesterone, and human epidermal growth factor receptor 2 statuses by reviewing pathology reports. Odds ratios (ORs) for NSW experience, age at commencement of NSW, frequency, and duration were estimated using conditional logistic regression and were adjusted for confounders such as parity and socioeconomic status–related factors.ResultsAmong 1721 pairs, 10.58% of cases and 9.59% of controls had ever engaged in NSW. NSW was not associated with breast cancer risk in terms of ever having night-shift exposure (adjusted OR was 1.11, 95% confidence interval [CI] =0.89–1.40), duration, frequency, or cumulative working time. The OR for >10 years of lifetime duration of NSW was 1.55 (95% CI 0.89–2.69, P=0.124). In addition, the OR for >35,000 hrs for cumulative frequency of night work was OR=1.42 (95% CI=0.73–2.74, P=0.304). There was no heterogeneity in ORs of ever having NSW and cumulative duration of NSW between four subtypes of breast cancer.ConclusionNSW including long-term and heavy working exposure was not associated with breast cancer risk.