| 1. |
- Ahearn, Thomas U., et al.
(author)
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Common variants in breast cancer risk loci predispose to distinct tumor subtypes
- 2022
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In: Breast Cancer Research. - : Springer Nature. - 1465-5411 .- 1465-542X. ; 24:1
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Journal article (peer-reviewed)abstract
- BackgroundGenome-wide association studies (GWAS) have identified multiple common breast cancer susceptibility variants. Many of these variants have differential associations by estrogen receptor (ER) status, but how these variants relate with other tumor features and intrinsic molecular subtypes is unclear.MethodsAmong 106,571 invasive breast cancer cases and 95,762 controls of European ancestry with data on 173 breast cancer variants identified in previous GWAS, we used novel two-stage polytomous logistic regression models to evaluate variants in relation to multiple tumor features (ER, progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and grade) adjusting for each other, and to intrinsic-like subtypes.ResultsEighty-five of 173 variants were associated with at least one tumor feature (false discovery rate < 5%), most commonly ER and grade, followed by PR and HER2. Models for intrinsic-like subtypes found nearly all of these variants (83 of 85) associated at p < 0.05 with risk for at least one luminal-like subtype, and approximately half (41 of 85) of the variants were associated with risk of at least one non-luminal subtype, including 32 variants associated with triple-negative (TN) disease. Ten variants were associated with risk of all subtypes in different magnitude. Five variants were associated with risk of luminal A-like and TN subtypes in opposite directions.ConclusionThis report demonstrates a high level of complexity in the etiology heterogeneity of breast cancer susceptibility variants and can inform investigations of subtype-specific risk prediction.
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| 2. |
- Barnekow, Elin, et al.
(author)
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A Swedish Familial Genome-Wide Haplotype Analysis Identified Five Novel Breast Cancer Susceptibility Loci on 9p24.3, 11q22.3, 15q11.2, 16q24.1 and Xq21.31
- 2023
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 24:5
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Journal article (peer-reviewed)abstract
- Most breast cancer heritability is unexplained. We hypothesized that analysis of unrelated familial cases in a GWAS context could enable the identification of novel susceptibility loci. In order to examine the association of a haplotype with breast cancer risk, we performed a genome-wide haplotype association study using a sliding window analysis of window sizes 1–25 SNPs in 650 familial invasive breast cancer cases and 5021 controls. We identified five novel risk loci on 9p24.3 (OR 3.4; p 4.9 × 10−11), 11q22.3 (OR 2.4; p 5.2 × 10−9), 15q11.2 (OR 3.6; p 2.3 × 10−8), 16q24.1 (OR 3; p 3 × 10−8) and Xq21.31 (OR 3.3; p 1.7 × 10−8) and confirmed three well-known loci on 10q25.13, 11q13.3, and 16q12.1. In total, 1593 significant risk haplotypes and 39 risk SNPs were distributed on the eight loci. In comparison with unselected breast cancer cases from a previous study, the OR was increased in the familial analysis in all eight loci. Analyzing familial cancer cases and controls enabled the identification of novel breast cancer susceptibility loci.
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| 3. |
- Barnekow, Elin, et al.
(author)
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A Swedish Genome-Wide Haplotype Association Analysis Identifies a Novel Breast Cancer Susceptibility Locus in 8p21.2 and Characterizes Three Loci on Chromosomes 10, 11 and 16
- 2022
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In: Cancers. - : MDPI AG. - 2072-6694. ; 14:5
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Journal article (peer-reviewed)abstract
- Background: The heritability of breast cancer is partly explained but much of the genetic contribution remains to be identified. Haplotypes are often used as markers of ethnicity as they are preserved through generations. We have previously demonstrated that haplotype analysis, in addition to standard SNP association studies, could give novel and more detailed information on genetic cancer susceptibility.Methods: In order to examine the association of a SNP or a haplotype to breast cancer risk, we performed a genome wide haplotype association study, using sliding window analysis of window sizes 1-25 and 50 SNPs, in 3200 Swedish breast cancer cases and 5021 controls.Results: We identified a novel breast cancer susceptibility locus in 8p21.1 (OR 2.08; p 3.92 x 10(-8)), confirmed three known loci in 10q26.13, 11q13.3, 16q12.1-2 and further identified novel subloci within these three loci. Altogether 76 risk SNPs, 3302 risk haplotypes of window size 2-25 and 113 risk haplotypes of window size 50 at p < 5 x 10(-8) on chromosomes 8, 10, 11 and 16 were identified. In the known loci haplotype analysis reached an OR of 1.48 in overall breast cancer and in familial cases OR 1.68.Conclusions: Analyzing haplotypes, rather than single variants, could detect novel susceptibility loci even in small study populations but the method requires a fairly homogenous study population.
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| 4. |
- Borgquist, Signe, et al.
(author)
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Long-term exposure to insulin and volumetric mammographic density : Observational and genetic associations in the Karma study
- 2018
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In: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 20:1
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Journal article (peer-reviewed)abstract
- Background: Long-term insulin exposure has been implicated in breast cancer etiology, but epidemiological evidence remains inconclusive. The aims of this study were to investigate the association of insulin therapy with mammographic density (MD) as an intermediate phenotype for breast cancer and to assess associations with long-term elevated circulating insulin levels using a genetic score comprising 18 insulin-associated variants. Methods: We used data from the KARolinska MAmmography (Karma) project, a Swedish mammography screening cohort. Insulin-treated patients with type 1 (T1D, n = 122) and type 2 (T2D, n = 237) diabetes were identified through linkage with the Prescribed Drug Register and age-matched to 1771 women without diabetes. We assessed associations with treatment duration and insulin glargine use, and we further examined MD differences using non-insulin-treated T2D patients as an active comparator. MD was measured using a fully automated volumetric method, and analyses were adjusted for multiple potential confounders. Associations with the insulin genetic score were assessed in 9437 study participants without diabetes. Results: Compared with age-matched women without diabetes, insulin-treated T1D patients had greater percent dense (8.7% vs. 11.4%) and absolute dense volumes (59.7 vs. 64.7 cm3), and a smaller absolute nondense volume (615 vs. 491 cm3). Similar associations were observed for insulin-treated T2D, and estimates were not materially different in analyses comparing insulin-treated T2D patients with T2D patients receiving noninsulin glucose-lowering medication. In both T1D and T2D, the magnitude of the association with the absolute dense volume was highest for long-term insulin therapy (≥ 5 years) and the long-acting insulin analog glargine. No consistent evidence of differential associations by insulin treatment duration or type was found for percent dense and absolute nondense volumes. Genetically predicted insulin levels were positively associated with percent dense and absolute dense volumes, but not with the absolute nondense volume (percentage difference [95% CI] per 1-SD increase in insulin genetic score = 0.8 [0.0; 1.6], 0.9 [0.1; 1.8], and 0.1 [- 0.8; 0.9], respectively). Conclusions: The consistency in direction of association for insulin treatment and the insulin genetic score with the absolute dense volume suggest a causal influence of long-term increased insulin exposure on mammographic dense breast tissue.
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| 5. |
- Brand, Judith S, et al.
(author)
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Chemotherapy, genetic susceptibility, and risk of venous thromboembolism in breast cancer patients
- 2016
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In: Clinical Cancer Research. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1078-0432. ; 22:21, s. 5249-5255
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Journal article (peer-reviewed)abstract
- Purpose: Venous thromboembolism (VTE) is highly heritable and a serious complication of cancer and its treatment. We examined the individual and joint effects of chemotherapy and genetic susceptibility on VTE risk in patients with breast cancer. Experimental design: A Swedish population-based study including 4,261 women diagnosed with primary invasive breast cancer between 2001 and 2008 in Stockholm, followed until 2012. Risk stratification by chemotherapy and genetic susceptibility [a polygenic risk score (PRS), including nine established VTE loci] was assessed using Kaplan-Meier and flexible parametric survival analyses, adjusting for patient, tumor, and treatment characteristics. Results: In total, 276 patients experienced a VTE event during a median follow-up of 7.6 years. Patients receiving chemotherapy [HR (95% CI) = 1.98; 1.40-2.80] and patients in the highest 5% of the PRS [HR (95% CI) = 1.90; 1.24-2.91] were at increased risk of developing VTE. Chemotherapy and PRS acted independently on VTE risk and the 1-year cumulative incidence in patients carrying both risk factors was 9.5% compared with 1.3% in patients not having these risk factors (P < 0.001). Stratified analyses by age showed that the risk-increasing effect of PRS was stronger in older patients (P interaction = 0.04), resulting in an excess risk among genetically susceptible patients receiving chemotherapy aged ≥ 60 years (1-year cumulative incidence = 25.0%). Conclusions: Risk stratification by chemotherapy and genetic susceptibility identifies patients with breast cancer at high VTE risk, who could potentially benefit from thromboprophylaxis. Our results further suggest that genetic testing is more informative in older patients with breast cancer.
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| 6. |
- Brand, Judith S, et al.
(author)
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Infection-related hospitalizations in breast cancer patients : risk and impact on prognosis
- 2016
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In: Journal of Infection. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0163-4453 .- 1532-2742.
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Infections are a common cause of hospitalization in breast cancer patients. We studied the risk, clinical characteristics and outcomes of infection-related hospitalizations in this patient population. METHODS: A Swedish registry-based study including 8338 breast cancer patients diagnosed between 2001 and 2008, followed prospectively for infection-related hospitalizations until 2010. Standardized incidence ratios (SIRs) were calculated using background rates from the general female population. Associations with clinical characteristics and mortality were analyzed using flexible parametric survival models. RESULTS: In total, 720 patients experienced an infection-related hospitalization during a median follow-up of 4.9 years. Infection rates were highest within the first year of diagnosis (SIR = 5.61, 95% CI; 4.98-6.32), and site-specific risks were most pronounced for sepsis (SIR = 3.14, 95% CI; 2.66-3.71) and skin infections (SIR = 2.80, 95% CI; 2.24-3.50). Older age at diagnosis, comorbidities, markers of tumor aggressiveness, chemotherapy and axillary node dissection were independent predictors of infectious disease risk. Infection-related hospitalizations were also independently associated with overall and breast cancer-specific death. CONCLUSIONS: A significant number of breast cancer patients are hospitalized with an infection following diagnosis, which in turn predicts poor prognosis. The risk profile of infection-related hospitalizations is multifactorial, including patient, tumor and treatment-related factors.
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| 7. |
- Brand, Judith S, et al.
(author)
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Time-dependent risk and predictors of venous thromboembolism in breast cancer patients: a population-based cohort study
- 2016
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In: Cancer. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0008-543X .- 1097-0142.
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Journal article (peer-reviewed)abstract
- BACKGROUND: Venous thromboembolism (VTE) is a serious complication of cancer and its treatment. The current study assessed the risk and clinical predictors of VTE in breast cancer patients by time since diagnosis. METHODS: This Swedish population-based study included 8338 breast cancer patients diagnosed from 2001 to 2008 in the Stockholm-Gotland region with complete follow-up until 2012. Their incidence of VTE was compared with the incidence among 39,013 age-matched reference individuals from the general population. Cox and flexible parametric models were used to examine associations with patient, tumor, and treatment characteristics, accounting for time-dependent effects. RESULTS: Over a median follow-up of 7.2 years, 426 breast cancer patients experienced a VTE event (cumulative incidence, 5.1%). The VTE incidence was 3-fold increased (hazard ratio [HR], 3.28; 95% confidence interval [CI], 2.87-3.74) in comparison with the incidence in the general population and was highest 6 months after diagnosis (HR, 8.62; 95% CI, 6.56-11.33) with a sustained increase in risk thereafter (HR at 5 years, 2.19; 95% CI, 1.80-2.67). Independent predictors of VTE included the following: older age, being overweight, preexisting VTE, comorbid disease, tumor size > 40 mm, progesterone receptor (PR)-negative status, more than 4 affected lymph nodes, and receipt of chemo- and endocrine therapy. The impact of chemotherapy was limited to early-onset VTE, whereas comorbid disease and PR-negative status were more strongly associated with late-onset events. CONCLUSIONS: This study confirms the long-term risk of VTE in breast cancer patients and identifies a comprehensive set of clinical risk predictors. Temporal associations with patient, tumor, and treatment characteristics provide insight into the time-dependent etiology of VTE.
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| 8. |
- Byström, Sanna, et al.
(author)
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Affinity proteomic profiling of plasma for proteins associated to area-based mammographic breast density
- 2018
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In: Breast Cancer Research. - : BIOMED CENTRAL LTD. - 1465-5411 .- 1465-542X. ; 20
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Journal article (peer-reviewed)abstract
- Background: Mammographic breast density is one of the strongest risk factors for breast cancer, but molecular understanding of how breast density relates to cancer risk is less complete. Studies of proteins in blood plasma, possibly associated with mammographic density, are well-suited as these allow large-scale analyses and might shed light on the association between breast cancer and breast density. Methods: Plasma samples from 1329 women in the Swedish KARMA project, without prior history of breast cancer, were profiled with antibody suspension bead array (SBA) assays. Two sample sets comprising 729 and 600 women were screened by two different SBAs targeting a total number of 357 proteins. Protein targets were selected through searching the literature, for either being related to breast cancer or for being linked to the extracellular matrix. Association between proteins and absolute area-based breast density (AD) was assessed by quantile regression, adjusting for age and body mass index (BMI). Results: Plasma profiling revealed linear association between 20 proteins and AD, concordant in the two sets of samples (p < 0.05). Plasma levels of seven proteins were positively associated and 13 proteins negatively associated with AD. For eleven of these proteins evidence for gene expression in breast tissue existed. Among these, ABCC11, TNFRSF10D, F11R and ERRF were positively associated with AD, and SHC1, CFLAR, ACOX2, ITGB6, RASSF1, FANCD2 and IRX5 were negatively associated with AD. Conclusions: Screening proteins in plasma indicates associations between breast density and processes of tissue homeostasis, DNA repair, cancer development and/or progression in breast cancer. Further validation and follow-up studies of the shortlisted protein candidates in independent cohorts will be needed to infer their role in breast density and its progression in premenopausal and postmenopausal women.
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| 9. |
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| 10. |
- Chen, Ruoqing, et al.
(author)
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Childhood injury after a parental cancer diagnosis
- 2015
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In: eLIFE. - Stockholm : eLife Sciences Publications Ltd. - 2050-084X. ; 4
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Journal article (peer-reviewed)abstract
- A parental cancer diagnosis is psychologically straining for the whole family. We investigated whether a parental cancer diagnosis is associated with a higher-than-expected risk of injury among children by using a Swedish nationwide register-based cohort study. Compared to children without parental cancer, children with parental cancer had a higher rate of hospital contact for injury during the first year after parental cancer diagnosis (hazard ratio [HR]=1.27, 95% confidence interval [CI]=1.22-1.33), especially when the parent had a comorbid psychiatric disorder after cancer diagnosis (HR=1.41, 95% CI=1.08-1.85). The rate increment declined during the second and third year after parental cancer diagnosis (HR=1.10, 95% CI=1.07-1.14) and became null afterwards (HR=1.01, 95% CI=0.99-1.03). Children with parental cancer also had a higher rate of repeated injuries than the other children (HR=1.13, 95% CI= 1.12-1.15). Given the high rate of injury among children in the general population, our findings may have important public health implications.
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| 11. |
- Chen, Ruoqing, et al.
(author)
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Impact of parental cancer on IQ, stress resilience, and physical fitness in young men
- 2018
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In: Clinical Epidemiology. - : DOVE Medical Press Ltd.. - 1179-1349. ; 10, s. 593-602
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Journal article (peer-reviewed)abstract
- Background: A parental cancer diagnosis is a stressful life event, potentially leading to increased risks of mental and physical problems among children. This study aimed to investigate the associations of parental cancer with IQ, stress resilience, and physical fitness of the affected men during early adulthood.Materials and methods: In this Swedish population-based study, we included 465,249 men born during 1973-1983 who underwent the military conscription examination around the age of 18 years. We identified cancer diagnoses among the parents of these men from the Cancer Register. IQ, stress resilience, and physical fitness of the men were assessed at the time of conscription and categorized into three levels: low, moderate, and high (reference category). We used multinomial logistic regression to assess the studied associations. Results: Overall, parental cancer was associated with higher risks of low stress resilience (relative risk ratio [RRR]: 1.09 [95% confidence interval (CI) 1.04-1.15]) and low physical fitness (RRR: 1.12 [95% CI 1.05-1.19]). Stronger associations were observed for parental cancer with a poor expected prognosis (low stress resilience: RRR: 1.59 [95% CI 1.31-1.94]; low physical fitness: RRR: 1.45 [95% CI 1.14-1.85]) and for parental death after cancer diagnosis (low stress resilience: RRR: 1.29 [95% CI 1.16-1.43]; low physical fitness: RRR: 1.40 [95% CI 1.23-1.59]). Although there was no overall association between parental cancer and IQ, parental death after cancer diagnosis was associated with a higher risk of low IQ (RRR: 1.11 [95% CI 1.01-1.24]).Conclusion: Parental cancer, particularly severe and fatal type, is associated with higher risks of low stress resilience and low physical fitness among men during early adulthood. Men who experienced parental death after cancer diagnosis also have a higher risk of low IQ.
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| 12. |
- Chen, Ruoqing, et al.
(author)
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Parental cancer diagnosis and child mortality : a population-based cohort study in Sweden
- 2015
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In: Cancer Epidemiology. - Stockholm : American Diabetes Association. - 1877-7821 .- 1877-783X. ; 39:1, s. 79-85
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Journal article (peer-reviewed)abstract
- Objective: Cancer diagnosis is known to induce severe psychological stress for the diagnosed patients; however, how it affects the next-of-kin is less well documented. This study aimed to assess the impact of parental cancer on the risk of childhood death.Methods: A population-based cohort study was conducted using the Swedish national registries, including 2,871,242 children followed during the period of 1991-2009. Parental cancer diagnosis was defined as a time-varying exposure. We used Cox proportional hazards regression to calculate the hazard ratio (HR) and its corresponding 95% confidence interval (CI) as an estimate of the association between parental cancer and childhood mortality. We adjusted for attained age, sex, gestational age, mode of delivery and birth weight of the child, maternal age at child's birth, as well as educational level and socioeconomic classification of the parents in the analyses.Results: Among 113,555 children with parental cancer, 127 deaths occurred during 561,198 person-years of follow-up. A parental cancer diagnosis was associated with an increased rate of death among children at the age of 1-18 (HR for all-cause death: 1.39; 95% CI: 1.16-1.66). For young children (aged 112), an increased rate was only noted for death due to cancer (HR: 2.06; 95% CI: 1.13-3.75) after parental cancer diagnosis. Among adolescents (aged 13-18), an increased rate was noted for all-cause death (HR: 1.52; 95% CI: 1.25-1.86), and for both non-cancer-related (HR: 1.43; 95% CI: 1.14-1.79) and cancer-related (HR: 2.07; 95% CI: 1.33-3.24) death in the exposed children.Conclusion: Children have an increased rate of death if they have a parent diagnosed with cancer as compared to children without such experience; this association appears to be slightly stronger among adolescents. (C) 2014 Elsevier Ltd. All rights reserved.
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| 13. |
- Chen, Ruoqing, et al.
(author)
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Psychiatric disorders among children of parents with cancer : a Swedish register-based matched cohort study
- 2018
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In: Psycho-Oncology. - : John Wiley & Sons. - 1057-9249 .- 1099-1611. ; 27:7, s. 1854-1860
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To investigate the risk of psychiatric disorders among children of parents with cancer in a nationwide population-based setting.METHODS: Based on Swedish national registers, the study included 101,339 children with parental cancer diagnosed either during pregnancy (N=1,047) or after birth (N=100,292) that were born during 1983-2000. For each exposed child, we randomly selected 10 unexposed children from the general population after individual matching by year of birth and sex. The matched cohort was followed during 2001-2010. Clinical diagnoses of psychiatric disorders and use of prescribed psychiatric medications were identified for all children. Cox regression and logistic regression were used to evaluate the associations of parental cancer with psychiatric disorder diagnosis and psychiatric medication use respectively.RESULTS: Parental cancer during pregnancy was not associated with the risk of psychiatric disorders overall, although paternal cancer during pregnancy was associated with a higher risk of psychiatric medication use among females. Parental cancer after birth was associated with higher risks of psychiatric disorder diagnoses, particularly stress reaction and adjustment disorders (males:hazard ratio[HR]:1.24, 95% confidence interval[CI]:1.08-1.43; females:HR:1.27, 95%CI:1.14-1.41), and use of psychiatric medication (males:odds ratio[OR]:1.09, 95%CI:1.04-1.13;females:OR:1.14, 95%CI:1.10-1.18). The positive associations were stronger for parental cancer with poor expected survival and for parental death after cancer diagnosis.CONCLUSIONS: Parental cancer, primarily the life-threatening cancer, might confer a higher risk of psychiatric disorders among children. These findings have potential implications for healthcare professionals in providing targeted support to children living with a parent with cancer.
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| 14. |
- Colzani, Edoardo, et al.
(author)
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Risk of hospitalization and death due to bone fractures after breast cancer: a registry-based cohort study
- 2016
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In: British Journal of Cancer. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 0007-0920 .- 1532-1827.
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Journal article (peer-reviewed)abstract
- BACKGROUND: Bone fractures may have an impact on prognosis of breast cancer. The long-term risks of bone fracture in breast cancer patients have not been thoroughly studied. METHODS: Poisson regression was used to investigate the incidence of hospitalisation due to bone fracture comparing women with and without breast cancer based on Swedish National registers. Cox regression was used to investigate the risk of being hospitalised with bone fracture, and subsequent risk of death, in a regional cohort of breast cancer patients. RESULTS: For breast cancer patients, the 5-year risk of bone fracture hospitalisation was 4.8% and the 30-day risk of death following a bone fracture hospitalisation was 2.0%. Compared with the general population, breast cancer patients had incidence rate ratios of 1.25 (95% CI: 1.23-1.28) and 1.18 (95% CI: 1.14-1.22) for hospitalisation due to any bone fracture and hip fracture, respectively. These ratios remained significantly increased for 10 years. Comorbidities (Charlson Comorbidity Index 1) were associated with the risk of being hospitalised with bone fracture. Women taking aromatase inhibitors were at an increased risk as compared with women taking tamoxifen (HR=1.48; 95% CI: 0.98-2.22). Breast cancer patients hospitalised for a bone fracture showed a higher risk of death (HR=1.83; 95% CI: 1.50-2.22) compared with those without bone fracture. CONCLUSIONS: Women with a previous breast cancer diagnosis are at an increased risk of hospitalisation due to a bone fracture, particularly if they have other comorbidities.
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| 15. |
- Couch, Fergus J., et al.
(author)
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Identification of four novel susceptibility loci for oestrogen receptor negative breast cancer
- 2016
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In: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 7:11375, s. 1-13
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Journal article (peer-reviewed)abstract
- Common variants in 94 loci have been associated with breast cancer including 15 loci with genome-wide significant associations (P<5 x 10(-8)) with oestrogen receptor (ER)-negative breast cancer and BRCA1-associated breast cancer risk. In this study, to identify new ER-negative susceptibility loci, we performed a meta-analysis of 11 genome-wide association studies (GWAS) consisting of 4,939 ER-negative cases and 14,352 controls, combined with 7,333 ER-negative cases and 42,468 controls and 15,252 BRCA1 mutation carriers genotyped on the iCOGS array. We identify four previously unidentified loci including two loci at 13q22 near KLF5, a 2p23.2 locus near WDR43 and a 2q33 locus near PPIL3 that display genome-wide significant associations with ER-negative breast cancer. In addition, 19 known breast cancer risk loci have genome-wide significant associations and 40 had moderate associations (P<0.05) with ER-negative disease. Using functional and eQTL studies we implicate TRMT61B and WDR43 at 2p23.2 and PPIL3 at 2q33 in ER-negative breast cancer aetiology. All ER-negative loci combined account for similar to 11% of familial relative risk for ER-negative disease and may contribute to improved ER-negative and BRCA1 breast cancer risk prediction.
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| 16. |
- Dixon-Suen, Suzanne C, et al.
(author)
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Physical activity, sedentary time and breast cancer risk : a Mendelian randomisation study
- 2022
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In: British Journal of Sports Medicine. - : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 56:20, s. 1157-1170
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Physical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using genotype, may be causally associated with breast cancer risk overall, pre/post-menopause, and by case-groups defined by tumour characteristics.METHODS: We performed two-sample inverse-variance-weighted MR using individual-level Breast Cancer Association Consortium case-control data from 130 957 European-ancestry women (69 838 invasive cases), and published UK Biobank data (n=91 105-377 234). Genetic instruments were single nucleotide polymorphisms (SNPs) associated in UK Biobank with wrist-worn accelerometer-measured overall physical activity (nsnps=5) or sedentary time (nsnps=6), or accelerometer-measured (nsnps=1) or self-reported (nsnps=5) vigorous physical activity.RESULTS: Greater genetically-predicted overall activity was associated with lower breast cancer overall risk (OR=0.59; 95% confidence interval (CI) 0.42 to 0.83 per-standard deviation (SD;~8 milligravities acceleration)) and for most case-groups. Genetically-predicted vigorous activity was associated with lower risk of pre/perimenopausal breast cancer (OR=0.62; 95% CI 0.45 to 0.87,≥3 vs. 0 self-reported days/week), with consistent estimates for most case-groups. Greater genetically-predicted sedentary time was associated with higher hormone-receptor-negative tumour risk (OR=1.77; 95% CI 1.07 to 2.92 per-SD (~7% time spent sedentary)), with elevated estimates for most case-groups. Results were robust to sensitivity analyses examining pleiotropy (including weighted-median-MR, MR-Egger).CONCLUSION: Our study provides strong evidence that greater overall physical activity, greater vigorous activity, and lower sedentary time are likely to reduce breast cancer risk. More widespread adoption of active lifestyles may reduce the burden from the most common cancer in women.
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| 17. |
- Eriksson, Louise, et al.
(author)
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Time from breast cancer diagnosis to therapeutic surgery and breast cancer prognosis : A population-based cohort study
- 2018
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In: International Journal of Cancer. - Stockholm : John Wiley & Sons. - 0020-7136 .- 1097-0215. ; 143:5, s. 1093-1104
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Journal article (peer-reviewed)abstract
- Theoretically, time from breast cancer diagnosis to therapeutic surgery should affect survival. However, it is unclear whether this holds true in a modern healthcare setting in which breast cancer surgery is carried out within weeks to months of diagnosis. This is a population- and register-based study of all women diagnosed with invasive breast cancer in the Stockholm-Gotland healthcare region in Sweden, 2001-2008, and who were initially operated. Follow-up of vital status ended 2014. 7,017 women were included in analysis. Our main outcome was overall survival. Main analyses were carried out using Cox proportional hazards models. We adjusted for likely confounders and stratified on mode of detection, tumor size and lymph node metastasis. We found that a longer interval between date of morphological diagnosis and therapeutic surgery was associated with a poorer prognosis. Assuming a linear association, the hazard rate of death from all causes increased by 1.011 (95% CI 1.006-1.017) per day. Comparing, for example, surgery 6 weeks after diagnosis to surgery 3 weeks after diagnosis, thereby confers a 1.26-fold increased hazard rate. The increase in hazard rate associated with surgical delay was strongest in women with largest tumors. Whilst there was a clear association between delays and survival in women without lymph node metastasis, the association may be attenuated in subgroups with increasing number of lymph node metastases. We found no evidence of an interaction between time to surgery and mode of detection. In conclusion, unwarranted delays to primary treatment of breast cancer should be avoided. What's new? Theoretically, an increase in the interval between breast-cancer diagnosis and therapeutic surgery should affect survival, but it is uncertain whether that holds true in a modern healthcare setting. In this prospective study, the authors found that even fairly short delays (on the order of days or weeks) from diagnosis to surgery are associated with decreased survival. These results suggest that the time between diagnosis and therapeutic surgery should be kept as short as possible without hampering diagnostic work-up and preoperative patient optimization.
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| 18. |
- Eriksson, Mikael, et al.
(author)
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Identification of Women at High Risk of Breast Cancer Who Need Supplemental Screening
- 2020
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In: Radiology. - : Radiological Society of North America (RSNA). - 1527-1315 .- 0033-8419. ; 297:2, s. 327-333
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Journal article (peer-reviewed)abstract
- Background Mammography screening reduces breast cancer mortality, but a proportion of breast cancers are missed and are detected at later stages or develop during between-screening intervals. Purpose To develop a risk model based on negative mammograms that identifies women likely to be diagnosed with breast cancer before or at the next screening examination. Materials and Methods This study was based on the prospective screening cohort Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA), 2011-2017. An image-based risk model was developed by using the Stratus method and computer-aided detection mammographic features (density, masses, microcalcifications), differences in the left and right breasts, and age. The lifestyle extended model included menopausal status, family history of breast cancer, body mass index, hormone replacement therapy, and use of tobacco and alcohol. The genetic extended model included a polygenic risk score with 313 single nucleotide polymorphisms. Age-adjusted relative risks and tumor subtype specific risks were estimated by using logistic regression, and absolute risks were calculated. Results Of 70 877 participants in the KARMA cohort, 974 incident cancers were sampled from 9376 healthy women (mean age, 54 years ± 10 [standard deviation]). The area under the receiver operating characteristic curve (AUC) for the image-based model was 0.73 (95% confidence interval [CI]: 0.71, 0.74). The AUCs for the lifestyle and genetic extended models were 0.74 (95% CI: 0.72, 0.75) and 0.77 (95% CI: 0.75, 0.79), respectively. There was a relative eightfold difference in risk between women at high risk and those at general risk. High-risk women were more likely to be diagnosed with stage II cancers and with tumors 20 mm or larger and were less likely to have stage I and estrogen receptor-positive tumors. The image-based model was validated in three external cohorts. Conclusion By combining three mammographic features, differences in the left and right breasts, and optionally lifestyle factors and family history and a polygenic risk score, the model identified women at high likelihood of being diagnosed with breast cancer within 2 years of a negative screening examination and in possible need of supplemental screening.
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| 19. |
- Eriksson, Mikael, et al.
(author)
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Low-Dose Tamoxifen for Mammographic Density Reduction : A Randomized Controlled Trial
- 2021
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In: Journal of Clinical Oncology. - 0732-183X. ; 39:17, s. 1899-
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Journal article (peer-reviewed)abstract
- PURPOSE: Tamoxifen prevents breast cancer in high-risk women and reduces mortality in the adjuvant setting. Mammographic density change is a proxy for tamoxifen therapy response. We tested whether lower doses of tamoxifen were noninferior to reduce mammographic density and associated with fewer symptoms.PATIENTS AND METHODS: Women, 40-74 years of age, participating in the Swedish mammography screening program were invited to the 6-month double-blind six-arm randomized placebo-controlled noninferiority dose-determination KARISMA phase II trial stratified by menopausal status (EudraCT 2016-000882-22). In all, 1,439 women were accrued with 1,230 participants accessible for intention-to-treat analysis. The primary outcome was proportion of women treated with placebo, 1, 2.5, 5, and 10 mg whose mammographic density decreased at least as much as the median reduction in the 20 mg arm. The noninferior margin was 17%. Secondary outcome was reduction of symptoms. Post hoc analyses were performed by menopausal status. Per-protocol population and full population were analyzed in sensitivity analysis.RESULTS: The 1,439 participants, 566 and 873 pre- and postmenopausal women, respectively, were recruited between October 1, 2016, and September 30, 2019. The participants had noninferior mammographic density reduction following 2.5, 5, and 10 mg tamoxifen compared with the median 10.1% decrease observed in the 20 mg group, a reduction confined to premenopausal women. Severe vasomotor symptoms (hot flashes, cold sweats, and night sweats) were reduced by approximately 50% in the 2.5, 5, and 10 mg groups compared with the 20 mg group.CONCLUSION: Premenopausal women showed noninferior magnitude of breast density decrease at 2.5 mg of tamoxifen, but fewer side effects compared with the standard dose of 20 mg. Future studies should test whether 2.5 mg of tamoxifen reduces the risk of primary breast cancer.
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| 20. |
- Escala-Garcia, Maria, et al.
(author)
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A network analysis to identify mediators of germline-driven differences in breast cancer prognosis
- 2020
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In: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 11:1
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Journal article (peer-reviewed)abstract
- Identifying the underlying genetic drivers of the heritability of breast cancer prognosis remains elusive. We adapt a network-based approach to handle underpowered complex datasets to provide new insights into the potential function of germline variants in breast cancer prognosis. This network-based analysis studies similar to 7.3 million variants in 84,457 breast cancer patients in relation to breast cancer survival and confirms the results on 12,381 independent patients. Aggregating the prognostic effects of genetic variants across multiple genes, we identify four gene modules associated with survival in estrogen receptor (ER)-negative and one in ER-positive disease. The modules show biological enrichment for cancer-related processes such as G-alpha signaling, circadian clock, angiogenesis, and Rho-GTPases in apoptosis.
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| 21. |
- Gabrielson, Marike, et al.
(author)
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Baseline breast tissue characteristics determine the effect of tamoxifen on mammographic density change
- 2024
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In: International Journal of Cancer. - 0020-7136 .- 1097-0215.
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Journal article (peer-reviewed)abstract
- Tamoxifen prevents recurrence of breast cancer and is also approved for preventive, risk-reducing, therapy. Tamoxifen alters the breast tissue composition and decreases the mammographic density. We aimed to test if baseline breast tissue composition influences tamoxifen-associated density change. This biopsy-based study included 83 participants randomised to 6 months daily intake of placebo, 20, 10, 5, 2.5, or 1 mg tamoxifen. The study is nested within the double-blinded tamoxifen dose-determination trial Karolinska Mammography Project for Risk Prediction of Breast Cancer Intervention (KARISMA) Study. Ultrasound-guided core-needle breast biopsies were collected at baseline before starting treatment. Biopsies were quantified for epithelial, stromal, and adipose distributions, and epithelial and stromal expression of proliferation marker Ki67, oestrogen receptor (ER) and progesterone receptor (PR). Mammographic density was measured using STRATUS. We found that greater mammographic density at baseline was positively associated with stromal area and inversely associated with adipose area and stromal expression of ER. Premenopausal women had greater mammographic density and epithelial tissue, and expressed more epithelial Ki67, PR, and stromal PR, compared to postmenopausal women. In women treated with tamoxifen (1–20 mg), greater density decrease was associated with higher baseline density, epithelial Ki67, and stromal PR. Women who responded to tamoxifen with a density decrease had on average 17% higher baseline density and a 2.2-fold higher PR expression compared to non-responders. Our results indicate that features in the normal breast tissue before tamoxifen exposure influences the tamoxifen-associated density decrease, and that the age-associated difference in density change may be related to age-dependant differences in expression of Ki67 and PR.
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| 22. |
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| 23. |
- Gabrielson, Marike, et al.
(author)
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Effects of tamoxifen on normal breast tissue histological composition : Results from a randomised six-arm placebo-controlled trial in healthy women
- 2023
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 152:11, s. 2362-2372
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Journal article (peer-reviewed)abstract
- Tamoxifen prevents recurrence of breast cancer and is suggested for preventive risk-reducing therapy. Tamoxifen reduces mammographic density, a proxy for therapy response, but little is known about its effects in remodelling normal breast tissue. Our study, a substudy within the double-blinded dose-determination trial KARISMA, investigated tamoxifen-specific changes in breast tissue composition and histological markers in healthy women. We included 83 healthy women randomised to 6 months daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. The groups were combined to “no dose” (0-1 mg), “low-dose” (2.5-5 mg) or “high-dose” (10-20 mg) of tamoxifen. Ultrasound-guided biopsies were collected before and after tamoxifen exposure. In each biopsy, epithelial, stromal and adipose tissues was quantified, and expression of epithelial and stromal Ki67, oestrogen receptor (ER) and progesterone receptor (PR) analysed. Mammographic density using STRATUS was measured at baseline and end-of-tamoxifen-exposure. We found that different doses of tamoxifen reduced mammographic density and glandular-epithelial area in premenopausal women and associated with reduced epithelium and increased adipose tissue. High-dose tamoxifen also decreased epithelial ER and PR expressions in premenopausal women. Premenopausal women with the greatest reduction in proliferation also had the greatest epithelial reduction. In postmenopausal women, high-dose tamoxifen decreased the epithelial area with no measurable density decrease. Tamoxifen at both low and high doses influences breast tissue composition and expression of histological markers in the normal breast. Our findings connect epithelial proliferation with tissue remodelling in premenopausal women and provide novel insights to understanding biological mechanisms of primary prevention with tamoxifen.
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| 24. |
- Gabrielson, Marike, et al.
(author)
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Hormonal determinants of mammographic density and density change
- 2020
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In: Breast Cancer Research. - : BMC. - 1465-5411 .- 1465-542X. ; 22:1
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Journal article (peer-reviewed)abstract
- Background Mammographic density (MD) is a strong risk factor for breast cancer. We examined how endogenous plasma hormones are associated with average MD area (cm(2)) and annual MD change (cm(2)/year). Methods This study within the prospective KARMA cohort included analyses of plasma hormones of 1040 women. Hormones from the progestogen (n = 3), androgen (n = 7), oestrogen (n = 2) and corticoid (n = 5) pathways were analysed by ultra-performance supercritical fluid chromatography-tandem mass spectrometry (UPSFC-MS/MS), as well as peptide hormones and proteins (n = 2). MD was measured as a dense area using the STRATUS method (mean over the left and right breasts) and mean annual MD change over time. Results Greater baseline mean MD was associated with overall higher concentrations of progesterone (average + 1.29 cm(2)per doubling of hormone concentration), 17OH-progesterone (+ 1.09 cm(2)), oesterone sulphate (+ 1.42 cm(2)), prolactin (+ 2.11 cm(2)) and SHBG (+ 4.18 cm(2)), and inversely associated with 11-deoxycortisol (- 1.33 cm(2)). The association between MD and progesterone was confined to the premenopausal women only. The overall annual MD change was - 0.8 cm(2). Hormones from the androgen pathway were statistically significantly associated with MD change. The annual MD change was - 0.96 cm(2)and - 1.16 cm(2)lesser, for women in the highest quartile concentrations of testosterone and free testosterone, respectively, compared to those with the lowest concentrations. Conclusions Our results suggest that, whereas hormones from the progestogen, oestrogen and corticoid pathways drive baseline MD, MD change over time is mainly driven by androgens. This study emphasises the complexity of risk factors for breast cancer and their mechanisms of action.
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| 25. |
- Gabrielson, Marike, et al.
(author)
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Inclusion of Endogenous Plasma Dehydroepiandrosterone Sulfate and Mammographic Density in Risk Prediction Models for Breast Cancer
- 2020
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In: Cancer Epidemiology, Biomarkers and Prevention. - : American Association For Cancer Research (AACR). - 1055-9965 .- 1538-7755. ; 29:3, s. 574-581
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Journal article (peer-reviewed)abstract
- Background: Endogenous hormones and mammographic density are risk factors for breast cancer. Joint analyses of the two may improve the ability to identify high-risk women.Methods: This study within the KARMA cohort included pre-diagnostic measures of plasma hormone levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), and mammographic density in 629 cases and 1,223 controls, not using menopausal hormones. We evaluated the area under the receiver-operating curve (AUC) for risk of breast cancer by adding DHEA, DHEAS, and mammographic density to the Gail or Tyrer-Cuzick 5-year risk scores or the CAD2Y 2-year risk score.Results: DHEAS and percentage density were independently and positively associated with breast cancer risk (P = 0.007 and P < 0.001, respectively) for postmenopausal, but not premenopausal, women. No significant association was seen for DHEA. In postmenopausal women, those in the highest tertiles of both DHEAS and density were at greatest risk of breast cancer (OR, 3.5; 95% confidence interval, 1.9-6.3) compared with the lowest tertiles. Adding DHEAS significantly improved the AUC for the Gail (+2.1 units, P = 0.008) and Tyrer-Cuzick (+1.3 units, P = 0.007) risk models. Adding DHEAS to the Gail and Tyrer-Cuzick models already including mammographic density further increased the AUC by 1.2 units (P = 0.006) and 0.4 units (P = 0.007), respectively, compared with only including density.Conclusions: DHEAS and mammographic density are independent risk factors for breast cancer and improve risk discrimination for postmenopausal breast cancer.Impact: Combining DHEAS and mammographic density could help identify women at high risk who may benefit from individualized breast cancer screening and/or preventive measures among postmenopausal women.
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