Population-based estimates of the relation between breast cancer risk, tumor subtype, and family history

Impact of breast cancer risk factors on clinically relevant prognostic biomarkers for primary breast cancer

Purpose

In addition to impacting incidence, risk factors for breast cancer may also influence recurrence and survival from the disease. However, it is unclear how these factors affect combinatorial biomarkers for aiding treatment decision-making in breast cancer.

Methods

Patients were 8179 women with histologically confirmed invasive breast cancer, diagnosed and treated in a large cancer hospital in Beijing, China. Individual clinicopathological (tumor size, grade, lymph nodes) and immunohistochemical (IHC: ER, PR, HER2, KI67) markers were used to define clinically relevant combinatorial prognostic biomarkers, including the Nottingham Prognostic Index (NPI: combining size, grade, nodes) and IHC4 score (combining ER, PR, HER2, KI67). Odds ratios (ORs) and 95% confidence intervals (CIs) for associations between breast cancer risk factors and quartiles (Q1–Q4) of NPI and IHC4 were assessed in multivariable polytomous logistic regression models.

Results

Overall, increasing parity (OR_trend(95% CI) = 1.20(1.05–1.37);P_trend = 0.007), overweight (OR(95% CI)_{vs normal} = 1.60(1.29–1.98)), and obesity (OR(95% CI) _{vs normal} = 2.12(1.43–3.14)) were associated with higher likelihood of developing tumors with high (Q4) versus low (Q1) NPI score. Conversely, increasing age (OR_trend(95% CI) = 0.75(0.66–0.84);P_trend < 0.001) and positive family history of breast cancer (FHBC) (OR(95% CI) = 0.66(0.45–0.95)) were inversely associated with NPI. Only body mass index (BMI) was associated with IHC4, with overweight (OR(95% CI) _{vs normal} = 0.82(0.66–1.02)) and obese (OR(95% CI) _{vs normal} = 0.52(0.36–0.76)) women less likely to develop high IHC4 tumors. Notably, elevated BMI was associated with higher NPI irrespective of hormone receptor-expression status.

Conclusions

Our findings indicate that factors affecting breast cancer incidence, particularly age, parity, FHBC, and BMI, may impact clinically relevant prognostic biomarkers with implications for surveillance, prognostication, and counseling.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06294-5.

Risk Prediction Model Development for Late On-Set Breast Cancer Screening in Low- and Middle-Income Societies: A Model Study for North Cyprus

Background: Early detection of breast cancer alters the prognosis and tools that can predict the risk for breast cancer in women will have a significant impact on healthcare systems in low- and middle-income regions, such as North Cyprus. Objective: In this study, we developed a simple breast cancer risk model for the women of North Cyprus. Methods: Data from 655 women, consisting of 318 breast cancer cases and 337 hospital-based controls, was used to develop and internally validate the model, external validation was carried out using, 653 women consisting of 126 cases and 527 controls. Data were obtained from medical records and interviews after informed consent. Results: A model was derived that consisted of age ≥50 years and <50 years and the presence and absence of >1 first-degree relatives (FDR) with breast cancer. From internal and external validations the model’s AUCs were, 0.66 (95% CI = 0.62–0.70) and 0.69 (95% CI = 0.63–0.74) respectively. Conclusions: A unique model for risk prediction of breast cancer was developed to aid in identifying high-risk women from North Cyprus that can benefit from mammogram screening. Further study on a large scale that includes environmental risk factors is warranted.

Premenopausal gynecologic surgery and survival among black and white women with breast cancer

PURPOSE

In the United States, hysterectomies and oophorectomies are frequently performed before menopause for benign conditions. The procedures are associated with reduced breast cancer-specific mortality among White women. The relationship between premenopausal gynecologic surgery and mortality in Black women with breast cancer is unknown.

METHODS

This investigation used incident invasive cases of breast cancer from Phases 1 and 2 of the Carolina Breast Cancer Study a population-based study that recruited Black and White women in North Carolina between 1993 and 2001. Premenopausal gynecologic surgery was operationalized in three categories: no surgery; hysterectomy with bilateral oophorectomy; hysterectomy with conservation of ≥ 1 ovary. Mortality was ascertained using the National Death Index, last updated in 2016. Multivariable-adjusted Cox Proportional Hazard Models were used to estimate the effect of premenopausal surgery on breast cancer-specific and all-cause mortality RESULTS: Hysterectomy with bilateral oophorectomy was associated with reduced breast cancer-specific mortality (HR 0.68; 95% CI 0.49, 0.96). White and Black women had a similar reduction in breast cancer-specific mortality. (HR among white: 0.66; 95% CI 0.43, 1.02), (HR among Black: 0.67; 95% CI 0.37, 1.21).

CONCLUSIONS

There was a similar reduction in breast cancer-specific mortality following premenopausal, pre-diagnosis hysterectomy with bilateral oophorectomy across both Black and White women.

Breast cancer in Mongolia: an increasingly important health policy issue

Breast cancer is a leading cause of cancer-related death for women in both developed and developing countries. The incidence and mortality of breast cancer in Mongolia, while low compared with other counties, has been increasing on an annual basis. In addition, in Mongolia, approximately 90% of the patients are diagnosed at a late stage, resulting in high mortality, with the majority of individuals diagnosed with breast cancer dying within 5 years of diagnosis. Breast cancer screening plays an important role in reducing mortality in Western countries and has been adopted by a number of Asian countries; however, no such approach exists in Mongolia. In a country of limited resources, implementation of expensive health strategies such as screening requires effective allocations of resources and the identification of the most effective imaging methods. This requirement relies on recent accurate data; however, at this time, there is a paucity of information around breast cancer in Mongolia. Until data around features of the disease are available, effective strategies to diagnose breast cancer that recognize the economic climate in Mongolia cannot be implemented and the impact of breast cancer is likely to increase.

Society of Surgical Oncology Breast Disease Working Group Statement on Prophylactic (Risk-Reducing) Mastectomy

Over the past several years, there has been an increasing rate of bilateral prophylactic mastectomy (BPM) and contralateral prophylactic mastectomy (CPM) surgeries. Since publication of the 2007 SSO position statement on the use of risk-reducing mastectomy, there have been significant advances in the understanding of breast cancer biology and treatment. The purpose of this manuscript is to review the current literature as a resource to facilitate a shared and informed decision-making process regarding the use of risk-reducing mastectomy.

Family History of Cancer in Relation to Breast Cancer Subtypes in African American Women

BACKGROUND

The evidence on the relation of family history of cancers other than breast cancer to breast cancer risk is conflicting, and most studies have not assessed specific breast cancer subtypes.

METHODS

We assessed the relation of first-degree family history of breast, prostate, lung, colorectal, ovarian, and cervical cancer and lymphoma or leukemia, to the risk of estrogen receptor-positive (ER(+)), ER(-), and triple-negative breast cancer in data from the African American Breast Cancer Epidemiology and Risk Consortium. Multivariable logistic regression models were used to calculate ORs and 95% confidence intervals (CI).

RESULTS

There were 3,023 ER(+) and 1,497 ER(-) breast cancer cases (including 696 triple-negative cases) and 17,420 controls. First-degree family history of breast cancer was associated with increased risk of each subtype: OR = 1.76 (95% CI, 1.57-1.97) for ER(+), 1.67 (1.42-1.95) for ER(-), and 1.72 (1.38-2.13) for triple-negative breast cancer. Family history of cervical cancer was associated with increased risk of ER(-) (OR = 2.39; 95% CI, 1.36-4.20), but not ER(+) cancer. Family history of both breast and prostate cancer was associated with increased risk of ER(+) (3.40; 2.42-4.79) and ER(-) (2.09; 1.21-3.63) cancer, but family history of both breast and lung cancer was associated only with ER(-) cancer (2.11; 1.29-3.46).

CONCLUSIONS

A family history of cancers other than breast may influence the risk of breast cancer, and associations may differ by subtype.

IMPACT

Greater surveillance and counseling for additional screening may be warranted for women with a family history of cancer.

Family history of breast and ovarian cancer and triple negative subtype in hispanic/latina women

Familial breast and ovarian cancer prevalence was assessed among 1150 women of Mexican descent enrolled in a case-only, binational breast cancer study. Logistic regression was conducted to compare odds of triple negative breast cancer (TNBC) to non-TNBC according to family history of breast and breast or ovarian cancer among 914 of these women. Prevalence of breast cancer family history in a first- and first- or second-degree relative was 13.1% and 24.1%, respectively; that for breast or ovarian cancer in a first-degree relative was 14.9%. After adjustment for age and country of residence, women with a first-degree relative with breast cancer were more likely to be diagnosed with TNBC than non-TNBC (OR=1.98; 95% CI, 1.26-3.11). The odds of TNBC compared to non-TNBC were 1.93 (95% CI, 1.26-2.97) for women with a first-degree relative with breast or ovarian cancer. There were non-significant stronger associations between family history and TNBC among women diagnosed at age <50 compared to ≥50 years for breast cancer in a first-degree relative (P-interaction = 0.14) and a first- or second-degree relative (P-interaction = 0.07). Findings suggest that familial breast cancers are associated with triple negative subtype, possibly related to BRCA mutations in Hispanic/Latina women, which are strongly associated with TNBC. Family history is an important tool to identify Hispanic/Latina women who may be at increased risk of TNBC, and could benefit from prevention and early detection strategies.

Heterogeneity of epidemiological factors by breast tumor subtypes in Korean women: a case-case study

Breast cancer is heterogeneous in clinical behavior by subtypes; however, it is unclear how this heterogeneity is related to epidemiological factors. To evaluate the differences in epidemiological factors by breast tumor subtypes, we investigated the associations of epidemiological factors between tumor subtypes in Korean women. From the Seoul Breast Cancer Study, a total of 3,058 patients with breast cancer were included in the analyses. Tumor subtypes were classified based on hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) statuses. The epidemiological factors of each subtype were compared through case-case analyses using multivariate a polytomous logistic regression model adjusted for age and recruiting centers. The distribution of the subtypes was as follows: 1,714 HR+ HER2- (56.0%), 414 HR+ HER2+ (13.5%), 423 HR- HER2+ (13.9%) and 507 HR- HER2- (16.6%) patients with breast cancer. There were significant differences in age, menopausal status, age at menarche, number of children, age at first full-term pregnancy (FFTP), duration of breastfeeding and duration of endogenous estrogen exposure between tumor subtypes (p < 0.05). Compared to HR+ HER2- patients, the other subtype patients showed more frequency in having more numbers of children and less frequency in having earlier menarche, later FFTP and longer endogenous estrogen exposure. Although HR- HER2+ patients were less obese, HR- HER2- patients were younger and more obese. In conclusion, age, body mass index and reproductive factors were differentially associated with breast tumor subtypes suggesting a possible distinct etiology for tumor progression.

The seed and soil hypothesis revisited: current state of knowledge of inherited genes on prognosis in breast cancer

The crucial event in the course of malignancies such as breast cancer is its metastatic spread from the primary tumor of origin to distant organs. The natural history of a tumor is determined by the expression of its genes, and in this sense, knowledge has advanced dramatically in recent decades. However, much less is known about the role that the patient plays in the behavior of a tumor. In this article, we review the evidence regarding the genetic background of the host in metastatic tumor dissemination, providing information from epidemiological studies as well as from animal models and human studies. Undoubtedly, the elucidation of possible interpersonal variability in susceptibility to developing metastases would significantly contribute to improve management of cancer patients.

Lack of association of genetic polymorphisms of angiotensin converting enzyme 1 and angiotensin II type 1 receptor with breast cancer risk in Iranian population

We aimed to investigate the association of insertion/deletion (I/D) and A1166C polymorphisms of angiotensin I converting enzyme 1 and angiotensin II type 1 receptor genes, respectively and their combination on breast cancer risk in an Iranian population. A case-control study (70 cases, 70 controls) was performed on an Iranian population. The I/D and A1166C polymorphisms were analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism PCR, respectively. The results revealed no significant difference between cases and controls in I/D (p = 0.14) and A1166C (p = 0.94) polymorphisms after adjustment for breast cancer known risk factors. In combined genotype analysis, considering DD and AA genotypes as low-risk genotypes, women with one and two high-risk genotypes (one high-risk genotype: adjusted odds ratio (OR), 1.24; two high-risk genotypes: adjusted OR, 1.97) were at higher risk for breast cancer. Also, the highest risk for breast cancer was seen in a subgroup of postmenopausal women carriers of two high-risk genotypes (adjusted OR, 2.41). In conclusion, I/D and A1166C polymorphisms are not significantly associated with breast cancer risk in the Iranian population; however, the combination of these two polymorphisms seems to have a synergic effect on the risk of breast cancer particularly in postmenopausal women, which may deserve consideration in large-scale case-control studies.

Factors related to the Performance of Mammography Screening among Women with a Family History of Breast Cancer in Korea

PURPOSE

Early diagnosis is the primary method aimed at controlling breast cancer. The purpose of this study was to analyze some factors affecting the performance of mammography screening among women with a family history of breast cancer in Korea.

METHODS

This study applied a descriptive design method through structured self-report questionnaires. The Care Seeking Behavior Theory provided a theoretical framework for the study. Factors measured in this study represent demographic, clinical, and psychosocial variables including anxiety, barriers, utility, habits, perception, and facilitators. A total of 212 participants, of at least 20 years old, were sampled from April 8, 2010 to March 31, 2011. The data was analyzed by logistic regression method using the Statistical Package for the Social Science 18.0 software.

RESULTS

Of the 212 participants, 122 women (57.5%) went through mammography screening. The results of the analysis showed that (a) age (Odds Ratio [OR]=1.10, p<.001), (b) facilitating influences (OR=1.83, p=.008), (c) perception of mammography importance (OR=1.92, p=.011), (d) barriers to mammography (OR=0.60, p=.031), and (e) utility of mammography (OR=2.01, p=.050) significantly affect mammography screening.

CONCLUSION

The results underscore the impact that psychosocial variables in obtaining mammography have on adherence to screening. Women with a family history of breast cancer should be given accurate information and recommendation about mammography by healthcare provider and a regular source of healthcare.

Young women with family history of breast cancer and their risk factors for benign breast disease

BACKGROUND

Breast cancer (BC) patients wonder how their daughters might reduce their risk. The authors investigated childhood/adolescent risk factors for benign breast disease (BBD), a well-documented risk factor for BC, among girls with a family history.

METHODS

GUTS (the Growing Up Today Study) includes females, aged 9 to 15 years in 1996, who completed annual questionnaires during 1996 to 2001, then in 2003, 2005, and 2007. Participants provided information regarding alcohol, menarche, height, and body mass index (BMI; kg/m(2)). Peak height growth velocity (PHV; in./y) was estimated from longitudinal heights. On 2005-2007 surveys, 6888 women (18-27 years old) reported whether they were diagnosed with biopsy-confirmed BBD (n = 67 cases); 6741 women (noncases) reported no BBD. Participants' mothers reported their own biopsy-confirmed BBD and BC, and BC in their sisters and mothers. Stratified by family history, logistic models investigated BBD risk factors.

RESULTS

Young women whose mothers or aunts had BC were more likely to be diagnosed with BBD (odds ratio [OR], 2.34; P = .01), as were those with maternal BBD (OR, 1.59; P = .095). Adolescents with BC family history (mother, aunt, grandmother) who consumed alcohol (7 drinks/wk) doubled their BBD risk (OR, 2.28; P = .01), similar to those with maternal BBD (OR, 1.96; P = .02). Girls whose mother or aunt had BC saw their BBD risk elevated with higher PHV (OR, 1.82 [inch/yr]; P = .05). Among girls with no family history, BBD risk appeared to be related to other factors: childhood BMI, adolescent waist circumference, and adult height.

CONCLUSIONS

Adolescents with family history may reduce their risk by avoiding alcohol. Separate risk factors were observed among girls with family history versus girls with no family history, possibly reflecting different causes of BC.

Family history of breast cancer in first-degree relatives and triple-negative breast cancer risk

Triple-negative breast cancer accounts for less than 20% of breast cancers overall, but is the predominant subtype among carriers of mutations in BRCA1. However, few studies have assessed the association between breast cancer family history and risk of triple-negative breast cancer. We examined the relationship between having a family history of breast cancer in first-degree relatives and risk of triple-negative breast cancer, and risk of two other breast cancer subtypes defined by tumor marker expression. We evaluated data collected by the Breast Cancer Surveillance Consortium from 2,599,946 mammograms on 1,054,466 women, among whom 15% reported a first-degree family history of breast cancer. Using Cox regression in this cohort, we evaluated subtype-specific associations between family history and risk of triple-negative (N = 705), estrogen receptor-positive (ER+, N = 10,026), and hormone receptor-negative/HER2-expressing (ER-/PR-/HER2+, N = 308) breast cancer among women aged 40-84 years. First-degree family history was similarly and significantly associated with an increased risk of all the subtypes [hazard ratio (HR) = 1.73, 95% confidence interval (CI): 1.43-2.09, HR = 1.62, 95% CI: 1.54-1.70, and HR = 1.56, 95% CI: 1.15-2.13, for triple-negative, ER+, and ER-/PR-/HER2+, respectively]. Risk of all the subtypes was most pronounced among women with at least two affected first-degree relatives (versus women with no affected first-degree relatives, HR(triple-negative) = 2.66, 95% CI: 1.66-4.27, HR(ER+) = 2.05, 95% CI: 1.79-2.36, HR(ER)-(/PR)-(/HER2+) = 2.25, 95% CI: 0.99-5.08). Having a first-degree family history of breast cancer was associated with an increased risk of triple-negative breast cancer with a magnitude of association similar to that for the predominant ER+ subtype and ER-/PR-/HER2+ breast cancer.

Family history, mammographic density, and risk of breast cancer

PURPOSE

Mammographic density is a strong and highly heritable risk factor for breast cancer. The purpose of this study was to examine the extent to which mammographic density explains the association of family history of breast cancer with risk of the disease.

SUBJECTS AND METHODS

We carried out three nested case-control studies in screening programs that included in total 2,322 subjects (1,164 cases and 1,158 controls). We estimated the independent and combined associations of family history and percent mammographic density at baseline with subsequent breast cancer risk.

RESULTS

After adjustment for age and other risk factors, compared with women with no affected first-degree relatives, percent mammographic density was 3.1% greater for women with one affected first-degree relative, and 7.0% greater for women with two or more affected relatives (P = 0.001 for linear trend across family history categories). The odds ratios for breast cancer risk were 1.37 [95% confidence interval (95% CI), 1.10-1.72] for having one affected relative, and 2.45 (95% CI, 1.30-4.62) for having two or more affected relatives (P for trend = 0.0002). Adjustment for percent mammographic density reduced these odds ratios by 16% and 14%, respectively. Percent mammographic density explained 14% (95% CI, 4-39%) of the association of family history (at least one affected first-degree relative) with breast cancer risk.

CONCLUSIONS

Percent mammographic density has features of an intermediate marker for breast cancer, and some of the genes that explain variation in percent mammographic density might be associated with familial risk of breast cancer.

Incorporating tumour pathology information into breast cancer risk prediction algorithms

INTRODUCTION

Mutations in BRCA1 and BRCA2 confer high risks of breast cancer and ovarian cancer. The risk prediction algorithm BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) may be used to compute the probabilities of carrying mutations in BRCA1 and BRCA2 and help to target mutation screening. Tumours from BRCA1 and BRCA2 mutation carriers display distinctive pathological features that could be used to better discriminate between BRCA1 mutation carriers, BRCA2 mutation carriers and noncarriers. In particular, oestrogen receptor (ER)-negative status, triple-negative (TN) status, and expression of basal markers are predictive of BRCA1 mutation carrier status.

METHODS

We extended BOADICEA by treating breast cancer subtypes as distinct disease end points. Age-specific expression of phenotypic markers in a series of tumours from 182 BRCA1 mutation carriers, 62 BRCA2 mutation carriers and 109 controls from the Breast Cancer Linkage Consortium, and over 300,000 tumours from the general population obtained from the Surveillance Epidemiology, and End Results database, were used to calculate age-specific and genotype-specific incidences of each disease end point. The probability that an individual carries a BRCA1 or BRCA2 mutation given their family history and tumour marker status of family members was computed in sample pedigrees.

RESULTS

The cumulative risk of ER-negative breast cancer by age 70 for BRCA1 mutation carriers was estimated to be 55% and the risk of ER-positive disease was 18%. The corresponding risks for BRCA2 mutation carriers were 21% and 44% for ER-negative and ER-positive disease, respectively. The predicted BRCA1 carrier probabilities among ER-positive breast cancer cases were less than 1% at all ages. For women diagnosed with breast cancer below age 50 years, these probabilities rose to more than 5% in ER-negative breast cancer, 7% in TN disease and 24% in TN breast cancer expressing both CK5/6 and CK14 cytokeratins. Large differences in mutation probabilities were observed by combining ER status and other informative markers with family history.

CONCLUSIONS

This approach combines both full pedigree and tumour subtype data to predict BRCA1/2 carrier probabilities. Prediction of BRCA1/2 carrier status, and hence selection of women for mutation screening, may be substantially improved by combining tumour pathology with family history of cancer.

Are there racial/ethnic disparities among women younger than 40 undergoing mammography?

While the probability of a woman developing invasive breast cancer at age <40 is low (<1%), mammography use reported among younger women (age <40) is substantial, and varies by race/ethnicity. Little detail is known about mammography use among women aged <40, particularly by race/ethnicity. We describe racial/ethnic differences in: (1) mammography indication after considering underlying risk factors (breast symptoms and family history); (2) follow-up recommendations, and (3) mammography outcomes for first mammograms in women aged <40. These 1996-2005 Breast Cancer Surveillance Consortium data are prospectively pooled from seven U.S. mammography registries. Our community-based sample included 99,615 women aged 18-39 who self-reported race/ethnicity and presented for a first mammogram (screening or diagnostic) with no history of breast cancer. Multivariable analyses controlled for registry site, age, family history of breast cancer, symptoms, and exam year. Overall, 73.6% of the women in our sample were seen for a screening mammogram. Following screening mammography, African American (AA) women were more likely than white women to be recommended for additional workup [relative risk (RR): 1.15 (95% CI: 1.07-1.23)]. Following diagnostic mammography, AA [RR: 1.30 (95% CI: 1.17-1.44)] and Asian [RR: 1.44 (95% CI: 1.26-1.64)] women were more likely to be recommended for biopsy, fine-needle aspiration, or surgical consultation. Depending on race/ethnicity, and considering the rate of true positive to total first screening mammograms of younger women, a women has a likelihood of a true positive of 1 in 363-1,122; she has a likelihood of a false positive of 1 in 7-10. This study of community-based practice found racial/ethnic variability in mammography indication, recommendations, and outcomes among women undergoing first mammography before 40. These findings highlight important areas for future research to understand the motivating factors for these practice patterns and the implications of early mammography use.

Familial relative risks for breast cancer by pathological subtype: a population-based cohort study

INTRODUCTION

The risk of breast cancer to first degree relatives of breast cancer patients is approximately twice that of the general population. Breast cancer, however, is a heterogeneous disease and it is plausible that the familial relative risk (FRR) for breast cancer may differ by the pathological subtype of the tumour. The contribution of genetic variants associated with breast cancer susceptibility to the subtype-specific FRR is still unclear.

METHODS

We computed breast cancer FRR for subtypes of breast cancer by comparing breast cancer incidence in relatives of breast cancer cases from a population-based series with known estrogen receptor (ER), progesterone receptor (PR) or human epidermal growth factor receptor 2 (HER2) status with that expected from the general population. We estimated the contribution to the FRR of genetic variants associated with breast cancer susceptibility using subtype-specific genotypic relative risks and allele frequencies for each variant.

RESULTS

At least one marker was measured for 4,590 breast cancer cases, who reported 9,014 affected and unaffected first-degree female relatives. There was no difference between the breast cancer FRR for relatives of patients with ER-negative (FRR = 1.78, 95% confidence intervals (CI): 1.44 to 2.11) and ER-positive disease (1.82, 95% CI: 1.67 to 1.98), P = 0.99. There was some suggestion that the breast cancer FRR for relatives of patients with ER-negative disease was higher than that for ER-positive disease for ages of the relative less than 50 years old (FRR = 2.96, 95% CI: 2.04 to 3.87; and 2.05, 95% CI: 1.70 to 2.40 respectively; P = 0.07), and that the breast cancer FRR for relatives of patients with ER-positive disease was higher than for ER-negative disease when the age of the relative was greater than 50 years (FRR = 1.76, 95% CI: 1.59 to 1.93; and 1.41, 95% CI: 1.08 to 1.74 respectively, P = 0.06). We estimated that mutations in BRCA1 and BRCA2 explain 32% of breast cancer FRR for relatives of patients with ER-negative and 9.4% of the breast cancer FRR for relatives of patients with ER-positive disease. Twelve recently identified common breast cancer susceptibility variants were estimated to explain 1.9% and 9.6% of the FRR to relatives of patients with ER-negative and ER-positive disease respectively.

CONCLUSIONS

FRR for breast cancer was significantly increased for both ER-negative and ER-positive disease. Including receptor status in conjunction with genetic status may aid risk prediction in women with a family history.

Family history of cancer and risk of breast cancer in the Black Women's Health Study

INTRODUCTION

Relatively little research has been conducted on familial breast cancer in African American women.

METHODS

Data from the Black Women's Health Study, a prospective cohort study of African American women, were used to assess breast cancer risk in relation to family history of cancer. Since 1995, participants have completed biennial postal questionnaires on health status, risk factors, and family history of cancer. Cox proportional hazards analyses were used to calculate incidence rate ratios (IRRs) and 95% confidence intervals (CI) for family history of breast and other types of cancer.

RESULTS

Among 57,364 participants who were cancer-free at baseline, 1,306 incident breast cancer cases occurred during 12 years of follow-up. The IRR for a first-degree family history of breast cancer relative to no family history was 1.78 (95% CI 1.55-2.06). IRRs varied by the age at diagnosis, from 1.60 (>or=age 55) to 2.76 (<age 35). Results were consistent across subtypes of breast tumor defined by estrogen and progesterone receptor status. Breast cancer risk was also associated with family history of colon cancer (IRR 1.35, 95% CI 1.12-1.63) and possibly with family history of leukemia (IRR 1.42, 95% CI 0.82-2.46).

CONCLUSIONS

These findings indicate a strong familial relationship for breast cancer in African American women. The associations with family history of colon cancer and leukemia warrant further investigation.

Differences in estrogen receptor subtype according to family history of breast cancer among Hispanic, but not non-Hispanic White women

BACKGROUND

Pathologic differences have been reported among breast tumors when comparing ethnic populations. Limited research has been done to evaluate the ethnic-specific relationships between breast cancer risk factors and the pathologic features of breast tumors.

METHODS

Given that genetic variation may contribute to ethnic-related etiologic differences in breast cancer, we hypothesized that tumor characteristics differ according to family history of breast cancer among Hispanic and non-Hispanic White (NHW) women. Logistic regression models were used to compute odds ratios (OR) and 95% confidence intervals (95% CI) to assess this relationship in the population-based, case-control 4-Corners Breast Cancer Study (1,537 cases and 2,452 controls).

RESULTS

Among Hispanic women, having a family history was associated with a 2.7-fold increased risk of estrogen receptor (ER) negative (95% CI, 1.59-4.44), but not ER positive tumors (OR, 1.04; 95% CI, 0.71-1.54) when compared with women without breast cancer. In contrast, there was an increased risk for ER positive (OR, 1.89; 95% CI, 1.50-2.38) and a marginally significant increased risk for ER negative tumors (OR, 1.41; 95% CI, 0.92-2.17) among NHW women. When comparing tumor characteristics among invasive cases, those with a family history also had a significantly higher proportion of ER negative tumors among Hispanics (39.2% versus 25.8%; P=0.02), but not among NHWs (16.3% versus 21.1%; P=0.13).

CONCLUSIONS

These results may reflect ethnic-specific predisposing genetic factors that promote the development of specific breast tumor subtypes, and emphasize the importance of evaluating the relationship between breast cancer risk factors and breast tumor subtypes among different ethnic populations.

Family history and age at onset of breast cancer in Hispanic and non-Hispanic white women

OBJECTIVES

To evaluate the association between family history of breast cancer and breast cancer risk among Hispanic and non-Hispanic white (NHW) women.

METHODS

Logistic regression models were used to compute unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) using data collected from the 4-Corners Breast Cancer Study, a population-based case-control study of breast cancer conducted in the Southwest United States (3,074 NHW and 1,647 Hispanic women).

RESULTS

The association between family history of breast cancer and early-onset breast cancer risk differs among NHW and Hispanic women. Among women <50 years old, having a family history of breast cancer was associated with a greater increase in risk among NHWs, with an OR of 2.34 (95% CI: 1.64-3.35) when compared to an OR of 1.32 (95% CI: 0.82-2.19) for Hispanics. This difference in risk was not observed among women 50 years and older, with an OR of 1.69 (95% CI: 1.34-2.13) for NHW and 1.47 (95% CI: 1.03-2.10) for Hispanics.

CONCLUSIONS

Family history of breast cancer poses a greater risk for early-onset breast cancers among NHW when compared to Hispanic women and may reflect ethnic differences in certain predisposing genetic factors that promote breast cancer development.

Oral contraceptives and the risk of breast cancer

BACKGROUND

It is uncertain whether the use of an oral contraceptive increases the risk of breast cancer later in life, when the incidence of breast cancer is increased. We conducted a population-based, case-control study to determine the risk of breast cancer among former and current users of oral contraceptives.

METHODS

We interviewed women who were 35 to 64 years old. A total of 4575 women with breast cancer and 4682 controls were interviewed. Conditional logistic regression was used to calculate odds ratios as estimates of the relative risk (incidence-density ratios) of breast cancer.

RESULTS

The relative risk was 1.0 (95 percent confidence interval, 0.8 to 1.3) for women who were currently using oral contraceptives and 0.9 (95 percent confidence interval, 0.8 to 1.0) for those who had previously used them. The relative risk did not increase consistently with longer periods of use or with higher doses of estrogen. The results were similar among white and black women. Use of oral contraceptives by women with a family history of breast cancer was not associated with an increased risk of breast cancer, nor was the initiation of oral-contraceptive use at a young age.

CONCLUSIONS

Among women from 35 to 64 years of age, current or former oral-contraceptive use was not associated with a significantly increased risk of breast cancer.