Understanding mathematical models for breast cancer risk assessment and counseling

Germline TP53 pathogenic variants and breast cancer: A narrative review

Approximately 10% of breast cancers are associated with the inheritance of a pathogenic variant (PV) in one of the breast cancer susceptibility genes. Multiple breast cancer predisposing genes, including TP53, are responsible for the increased breast cancer risk. Tumor protein-53 (TP53) germline PVs are associated with Li-Fraumeni syndrome, a rare autosomal dominant inherited cancer predisposition syndrome associated with early-onset pediatric and multiple primary cancers such as soft tissue and bone sarcomas, breast cancer, brain tumors, adrenocortical carcinomas and leukemias. Women harboring a TP53 PV carry a lifetime risk of developing breast cancer of 80-90%. The aim of the present narrative review is to provide a comprehensive overview of the criteria for offering TP53 testing, prevalence of TP53 carriers among patients with breast cancer, and what is known about its prognostic and therapeutic implications. A summary of the current indications of secondary cancer surveillance and survivorship issues are also provided. Finally, the spectrum of TP53 alteration and testing is discussed. The optimal strategies for the treatment of breast cancer in patients harboring TP53 PVs poses certain challenges. Current guidelines favor the option of performing mastectomy rather than lumpectomy to avoid adjuvant radiotherapy and subsequent risk of radiation-induced second primary malignancies, with careful consideration of radiation when indicated post-mastectomy. Some studies suggest that patients with breast cancer and germline TP53 PV might have worse survival outcomes compared to patients with breast cancer and wild type germline TP53 status. Annual breast magnetic resonance imaging (MRI) and whole-body MRI are recommended as secondary prevention.

Statistical methods for Mendelian models with multiple genes and cancers

Risk evaluation to identify individuals who are at greater risk of cancer as a result of heritable pathogenic variants is a valuable component of individualized clinical management. Using principles of Mendelian genetics, Bayesian probability theory, and variant-specific knowledge, Mendelian models derive the probability of carrying a pathogenic variant and developing cancer in the future, based on family history. Existing Mendelian models are widely employed, but are generally limited to specific genes and syndromes. However, the upsurge of multigene panel germline testing has spurred the discovery of many new gene-cancer associations that are not presently accounted for in these models. We have developed PanelPRO, a flexible, efficient Mendelian risk prediction framework that can incorporate an arbitrary number of genes and cancers, overcoming the computational challenges that arise because of the increased model complexity. We implement an 11-gene, 11-cancer model, the largest Mendelian model created thus far, based on this framework. Using simulations and a clinical cohort with germline panel testing data, we evaluate model performance, validate the reverse-compatibility of our approach with existing Mendelian models, and illustrate its usage. Our implementation is freely available for research use in the PanelPRO R package.

Predictive model of stunting in the Central Andean region of Peru based on socioeconomic and agri-food determinants

Objectives

A limitation in the design and monitoring of public health policies is the lack of conceptual models to explain their results. The objective of this study was to develop a predictive model of stunting in children under 5 years of age in the central Andean region of Peru, using socioeconomic and agro-productive predictors.

Study design

Cross-sectional data of 380 families in 15 districts of the central region of Peru. WHO criteria were used to define stunting prediction model.

Methods

An explanatory and predictive study of stunting in children was carried out considering causality criteria through Chi-square tests and bivariate logistic regression. Family food production, maternal education, breastfeeding practices and others determinant related to rural zone conditions were considered as explanatory variables in stunting of children under 5 years old. Three exhaustive models for predicted the presence of stunting was developed.

Results

Stunting percentage was 40.3. To Hosmer and Lemeshow test, the best fit was the model that considered the level of maternal education, timely consumption of colostrum, birth weight and guinea pig rearing, having high reliability (P ​< ​0.05).

Conclusions

A predictive model for early detection of stunting risk in rural areas of the Andean region was developed based on simple and easily applied indicators. Effective policies are required to improve the feeding practices of pregnant women, increase breastfeeding and promote guinea pig raising for self-consumption and improve the nutritional status of children.

Utilization of breast cancer risk prediction models by cancer genetic counselors in clinical practice predominantly in the United States

Risk assessment in cancer genetic counseling is essential in identifying individuals at high risk for developing breast cancer to recommend appropriate screening and management options. Historically, many breast cancer risk prediction models were developed to calculate an individual's risk to develop breast cancer or to carry a pathogenic variant in the BRCA1 or BRCA2 genes. However, how or when genetic counselors use these models in clinical settings is currently unknown. We explored genetic counselors' breast cancer risk model usage patterns including frequency of use, reasons for using or not using models, and change in usage since the adoption of multi-gene panel testing. An online survey was developed and sent to members of the National Society of Genetic Counselors; board-certified genetic counselors whose practice included cancer genetic counseling were eligible to participate in the study. The response rate was estimated at 23% (243/1,058), and respondents were predominantly working in the United States. The results showed that 93% of all respondents use at least one breast cancer risk prediction model in their clinical practice. Among the six risk models selected for the study, the Tyrer-Cuzick (IBIS) model was used most frequently (95%), and the BOADICEA model was used least (40%). Determining increased or decreased surveillance and breast MRI eligibility were the two most common reasons for most model usage, while time consumption and difficulty in navigation were the two most common reasons for not using models. This study provides insight into perceived benefits and limitations of risk models in clinical use in the United States, which may be useful information for software developers, genetic counseling program curriculum developers, and currently practicing cancer genetic counselors.

A likelihood-based approach to assessing frequency of pathogenicity among variants of unknown significance in susceptibility genes

Commercialized multigene panel testing brings unprecedented opportunities to understand germline genetic contributions to hereditary cancers. Most genetic testing companies classify the pathogenicity of variants as pathogenic, benign, or variants of unknown significance (VUSs). The unknown pathogenicity of VUSs poses serious challenges to clinical decision-making. This study aims to assess the frequency of VUSs that are likely pathogenic in disease-susceptibility genes. Using estimates of probands' probability of having a pathogenic mutation (ie, the carrier score) based on a family history probabilistic risk prediction model, we assume the carrier score distribution for probands with VUSs is a mixture of the carrier score distribution for probands with positive results and the carrier score distribution for probands with negative results. Under this mixture model, we propose a likelihood-based approach to assess the frequency of pathogenicity among probands with VUSs, while accounting for the existence of possible pathogenic mutations on genes not tested. We conducted simulations to assess the performance of the approach and show that under various settings, the approach performs well with very little bias in the estimated proportion of VUSs that are likely pathogenic. We also estimate the positive predictive value across the entire range of carrier scores. We apply our approach to the USC-Stanford Hereditary Cancer Panel Testing cohort, and estimate the proportion of probands that have VUSs in BRCA1/2 that are likely pathogenic to be 10.12% [95%CI: 0%, 43.04%]. This approach will enable clinicians to target high-risk patients who have VUSs, allowing for early prevention interventions.

Towards a more precise and individualized assessment of breast cancer risk

Many clinically based models are available for breast cancer risk assessment; however, these models are not particularly useful at the individual level, despite being designed with that intent. There is, therefore, a significant need for improved, precise individualized risk assessment. In this Research Perspective, we highlight commonly used clinical risk assessment models and recent scientific advances to individualize risk assessment using precision biomarkers. Genome-wide association studies have identified >100 single nucleotide polymorphisms (SNPs) associated with breast cancer risk, and polygenic risk scores (PRS) have been developed by several groups using this information. The ability of a PRS to improve risk assessment is promising; however, validation in both genetically and ethnically diverse populations is needed. Additionally, novel classes of biomarkers, such as microRNAs, may capture clinically relevant information based on epigenetic regulation of gene expression. Our group has recently identified a circulating-microRNA signature predictive of long-term breast cancer in a prospective cohort of high-risk women. While progress has been made, the importance of accurate risk assessment cannot be understated. Precision risk assessment will identify those women at greatest risk of developing breast cancer, thus avoiding overtreatment of women at average risk and identifying the most appropriate candidates for chemoprevention or surgical prevention.

The Application of Gail Model to Predict the Risk of Developing Breast Cancer among Jordanian Women

Background and Objectives. Breast cancer has been the most common cancer affecting women in Jordan. In the process of implementing breast cancer prevention and early detection programs, individualized risk assessment can add to the cost-effectiveness of such interventions. Gail model is a widely used tool to stratify patients into different risk categories. However, concerns about its applicability across different ethnic groups do exist. In this study, we report our experience with the application of a modified version of this model among Jordanian women.

Efficient computation of the joint probability of multiple inherited risk alleles from pedigree data

The Elston-Stewart peeling algorithm enables estimation of an individual's probability of harboring germline risk alleles based on pedigree data, and serves as the computational backbone of important genetic counseling tools. However, it remains limited to the analysis of risk alleles at a small number of genetic loci because its computing time grows exponentially with the number of loci considered. We propose a novel, approximate version of this algorithm, dubbed the peeling and paring algorithm, which scales polynomially in the number of loci. This allows extending peeling-based models to include many genetic loci. The algorithm creates a trade-off between accuracy and speed, and allows the user to control this trade-off. We provide exact bounds on the approximation error and evaluate it in realistic simulations. Results show that the loss of accuracy due to the approximation is negligible in important applications. This algorithm will improve genetic counseling tools by increasing the number of pathogenic risk alleles that can be addressed. To illustrate we create an extended five genes version of BRCAPRO, a widely used model for estimating the carrier probabilities of BRCA1 and BRCA2 risk alleles and assess its computational properties.

Breast cancer in black African women: a changing situation

Black African women in rural South Africa have a very low incidence rate of breast cancer, 5-10 per 100,000. The rate, however, is rising in the considerably increasing urban population. During the period 1994 to 1999 in Durban, enquiries revealed an average of 57 urban patients admitted to hospital each year, from a population of about 600,000 African women, indicating an age-adjusted annual incidence rate of 15.1 per 100,000. This incidence rate is very low in comparison with those in developed populations, which range from 40 to 89 per 100,000.

In the African patients studied, the mean age on admission was relatively young, 54.1±10.9 years, almost a decade earlier than patients of developed populations. Moreover, the disease was very far advanced; 21.1% were at Stage III and 63.1% at Stage IV. As to exposure to risk factors, African women in general are characterised by certain protective factors. These factors, which closely resemble those of importance in patients in developed populations are, late menarche, early age at birth of first child, high parity (with usually prolonged lactation), and being physically active. However, with ongoing changes in the lifestyle of urban African women, the protective factors are decreasing in their intensity. Changes in these respects have been associated with rises in the disease’s incidence rate. Clearly, because of the late stage of the disease at the time of the patients’ admission to hospital, and hence their poor survival rate, intensive efforts should be made to educate women to seek help at an early stage of their disease. For its avoidance, feasible protective or restraining measures are primarily to adopt a ‘prudent’ lifestyle, in respect of both dietary and non-dietary components. However, the chances of these measures being meaningfully adopted in African urban communities, unfortunately, are negligible. In consequence, further increases in incidence rate would seem inevitable.

Correlational study on mitochondrial DNA mutations as potential risk factors in breast cancer

The presented study performed an mtDNA genome-wide association analysis to screen the peripheral blood of breast cancer patients for high-risk germline mutations. Unlike previous studies, which have used breast tissue in analyzing somatic mutations, we looked for germline mutations in our study, since they are better predictors of breast cancer in high-risk groups, facilitate early, non-invasive diagnoses of breast cancer and may provide a broader spectrum of therapeutic options. The data comprised 22 samples of healthy group and 83 samples from breast cancer patients. The sequencing data showed 170 mtDNA mutations in the healthy group and 393 mtDNA mutations in the disease group. Of these, 283 mtDNA mutations (88 in the healthy group and 232 in the disease group) had never been reported in the literature. Moreover, correlation analysis indicated there was a significant difference in 32 mtDNA mutations. According to our relative risk analysis of these 32 mtDNA mutations, 27 of the total had odds ratio values (ORs) of less than 1, meaning that these mutations have a potentially protective role to play in breast cancer. The remaining 5 mtDNA mutations, RNR2-2463 indelA, COX1-6296 C>A, COX1-6298 indelT, ATP6-8860 A>G, and ND5-13327 indelA, whose ORs were 8.050, 4.464, 4.464, 5.254 and 4.853, respectively, were regarded as risk factors of increased breast cancer. The five mutations identified here may serve as novel indicators of breast cancer and may have future therapeutic applications. In addition, the use of peripheral blood samples was procedurally simple and could be applied as a non-invasive diagnostic technique.

Breast cancer risk and early diagnosis applications in Turkish women aged 50 and over

BACKGROUND

The aim of the study was to determine breast cancer risk and early diagnosis applications in women aged ≥50.

MATERIALS AND METHODS

This cross-sectional, descriptive field study focused on a population of 4,815 in Mansurog?lu with a 55.1% participation rate in screening. In the study, body mass index (BMI) was also evaluated in the calculation of breast cancer risk by the Breast Cancer Risk Assessment Tool (BCRA) (also called the "Gail Risk Assessment Tool") . The interviewers had a three-hour training provided by the researchers, during which interactive training methods were used and applications were supported with role-plays.

RESULTS

The mean age of the women participating in the study was 60.1±8.80. Of these women, 57.3% were in the 50-59 age group, 71.7% were married, 57.3% were primary school graduates and 61.7% were housewives. Breast-cancer development rate was 7.4% in the women participating in the study. When they were evaluated according to their relationship with those with breast cancer, it was determined that 73.0% of them had first- degree relatives with breast cancer. According to the assessment based on the Gail method, the women's breast cancer development risk within the next 5 years was 17.6%, whereas their calculated lifetime risk was found to be as low as 0.2%. Statistically significant differences (P=0.000) were determined between performing BSE - CBE and socio-demographic factors.

CONCLUSIONS

It was determined that 17.6% of the participants had breast cancer risk. There was no statistically significant difference between the women with and without breast cancer risk in terms of early diagnosis practices, which can be regarded as a remarkable finding. It was planned to provide training about the early diagnosis and treatment of breast cancer for people with high-risk scores, and to conduct population-based breast cancer screening programs.

Obesity is a significant risk factor for breast cancer in Arab women

Background

Breast cancer (BC) is the most common malignancy and the leading cause of cancer-related death amongst women worldwide. The risk factors of this disease are numerous, and their prevalence varies between racial and ethnic groups as well as geographical regions. Therefore, we sought to delineate the association of socio-demographic, reproductive and life-style related risk factors with breast cancer in the Arab population.

Methods

Unmatched case-control study was conducted in the kingdom of Saudi Arabia using 534 cases of histologically confirmed breast cancer and 638 controls. Controls were randomly selected from primary health care visits and were free of breast cancer. Unconditional logistic regression analysis was performed to estimate odds ratios (ORs) and to examine the predictive effect of each factor on risk for BC. All study participants were interviewed by trained interviewers at hospital (cases) or at primary health care centers (controls).

Results

A total of 1172 women were eligible for this study, of which 281 (24.0%) were aged ≤35 years, 22.9% illiterate, 43.6% employed, 89.5% married, and 38.1% were obese. Grade III tumors constituted 38.4% of cases. Tumor stage I was 7.5%; II, 50.7%; II, 30.9%; IV, 11.1%. We have shown strong association between breast cancer among Arab females and obesity (OR =2.29, 95% CI 1.68-3.13), positive family history of breast cancer (OR =2.31, 95% CI 1.60 – 3.32), the use of hormonal replacement therapy (OR =2.25, 95% CI 1.65 – 3.08), post-menopause (OR =1.72, 95% CI 1.25 – 2.38), lack of education (OR =9.09, 95% CI 5.88 – 14.29), and never breastfeed (OR =1.89, 95% CI 1.19 – 2.94).

Conclusion

These results indicate the presence of classical risk factors established in the western countries, and also some specific ones, which may result from genetic and/or environmental factors. Thereby, these findings will be of great value to establish adequate evidence-based awareness and preventative measures in the Arab world.

An internal performance assessment of CancerGene Connect: an electronic tool to streamline, measure and improve the genetic counseling process

CancerGene Connect (CGC) is a web-based program that combines the collection of family and medical history, cancer risk assessment, psychosocial assessment, report templates, a result tracking system, and a patient follow up system. The performance of CGC was assessed in several ways: pre-appointment completion data analyzed for demographic and health variables; a time study to assess overall time per case and to compare the data entry by the genetic counselor compared to the patient, and a measured quality assessment of the program via observation and interview of patients. Prior to their appointment, 52.3% of 2,414 patients completed the online patient questionnaire section of CGC. There were significant differences in completion rates among racial and ethnic groups. County hospital patients were less likely to complete the questionnaire than insured patients (p < 0.0001); and likewise uninsured patients and patients with Medicare/Medicaid were less likely to complete the questionnaire than private patients (p < 0.0001). The average genetic counseling time per case was 82 min, with no significant differences whether the counselor or the patient completed CGC. CGC reduces genetic counselor time by approximately 14-46% compared to average time per case using traditional risk assessment and documentation methods previously reported. All surveyed users felt the questionnaire was easy to understand. CGC is an effective tool that streamlines workflow, and provides a standardized data collection tool that can be used to evaluate and improve the genetic counseling process.

Intentions for risk-reducing surgery among high-risk women referred for BRCA1/BRCA2 genetic counseling

OBJECTIVE

Genetic testing for breast and ovarian cancer susceptibility is now part of routine clinical practice. Although rates of risk-reducing surgery following genetic testing have been increasing, little is known about attitudes toward risk-reducing surgery in women prior to genetic counseling and testing. This study examines correlates of patient intentions to undergo risk-reducing mastectomy (RRM) and risk-reducing oophorectomy (RRO).

METHODS

Participants were 696 women, ages 21-85, who sought breast cancer gene 1 and 2 (BRCA1/2) genetic counseling and had at least a 10% risk of carrying a mutation. The sample included women who were affected with breast or ovarian cancer and unaffected women with a known familial BRCA1/2 mutation. Participants completed a precounseling telephone questionnaire.

RESULTS

Prior to receiving genetic counseling, 23.3% of participants were considering RRM and 42.5% were considering RRO. Variables that were independently associated with RRM intentions were cancer-specific distress (OR = 1.14, 95% CI = 1.03-1.26), perceived risk of breast cancer (OR = 1.16, 95% CI = 1.05-1.28), education (OR = 1.76, 95% CI = 1.03-2.99), and age (OR = 0.96, 95% CI = 0.95-0.98). Predictors of RRO intentions were perceived risk for ovarian cancer (OR = 1.25, 95% CI = 1.14-1.37), perceived risk of carrying a BRCA1/2 mutation (OR = 1.74, 95% CI = 1.15-2.62), marital status (OR = 1.92, 95% CI = 1.34-2.76), and age (OR = 1.02, 95% CI = 1.00-1.03).

CONCLUSIONS

Because precounseling intentions predict subsequent risk-reducing surgery decisions, this study identified patient factors associated with surgical intentions. These factors reinforce the critical role for pretest genetic counseling in communicating accurate risk estimates and management options, and addressing psychosocial concerns, to facilitate informed decision making regarding RRM and RRO.

A case-control study on risk factors of breast cancer in China

INTRODUCTION

To screen the risk factors associated with breast cancer among Chinese women in order to evaluate the individual risk of developing breast cancer among women in China.

MATERIAL AND METHODS

A case-control study on 416 breast cancer patients and 1156 matched controls was conducted in 14 hospitals in 8 provinces of China in 2008. Controls were age- and region-matched to the cases. Clinicians conducted in-person interviews with the subjects to collect information on demographics and suspected risk factors for breast cancer that are known worldwide. Conditional logistic regression was used to derive odds ratios (OR) and 95% confidence intervals (CI) for the associations between risk factors and breast cancer.

RESULTS

Compared with matched controls, women with breast cancer were significantly more likely to have higher body mass index (BMI, OR = 4.07, 95% CI: 2.98-5.55), history of benign breast disease (BBD) biopsy (OR = 1.68, 95% CI: 1.19-2.38), older age of menarche (AOM) (OR = 1.41, 95% CI: 1.07-1.87), stress anticipation (SA), for grade 1-4, OR = 2.15, 95% CI: 1.26-3.66; for grade 5-9, OR = 3.48, 95% CI: 2.03-5.95) and menopause (OR = 2.22, 95% CI: 1.50-3.282) at the level of p < 0.05. Family history of breast cancer (FHBC) in first-degree relatives (OR = 1.66, 95% CI: 0.77-3.59) and use of oral contraceptives (OC) (OR = 1.59, 95% CI: 0.83-3.05) were associated with an increased risk of breast cancer at the level of p < 0.20.

CONCLUSIONS

Our results showed that BMI, history of BBD biopsy, older AOM, SA and menopause were associated with increased risk of breast cancer among Chinese women. The findings derived from the study provided some suggestions for population-based prevention and control of breast cancer in China.

Hereditary breast and ovarian cancer and other hereditary syndromes: using technology to identify carriers

PURPOSE AND METHODS

Most patients who harbor a genetic mutation for hereditary breast cancer have not been identified, despite the availability of genetic testing. Developing an effective approach to the identification of high-risk individuals is the key to preventing and/or providing early diagnosis of cancer in this patient population. This educational review addresses these issues.

RESULTS AND DISCUSSION

Using data available on the internet, and making assumptions regarding the types and results of genetic testing, we have estimated the number of mutation carriers in the country and the number who have been tested and identified as such. Overall, our ability to fund and more effectively manage carriers is weak. A technological solution is discussed.

Evolutionary dynamics of BRCA1 alterations in breast tumorigenesis

Cancer results from the accumulation of alterations in oncogenes and tumor suppressor genes. Tumor suppressors are classically defined as genes which contribute to tumorigenesis if their function is lost. Genetic or epigenetic alterations inactivating such genes may arise during somatic cell divisions or alternatively may be inherited from a parent. One notable exception to this rule is the BRCA1 tumor suppressor that predisposes to hereditary breast cancer when lost. Genetic alterations of this gene are hardly ever observed in sporadic breast cancer, while individuals harboring a germline mutation readily accumulate a second alteration inactivating the remaining allele--a finding which represents a conundrum in cancer genetics. In this paper, we present a novel mathematical framework of sporadic and hereditary breast tumorigenesis. We study the dynamics of genetic alterations driving breast tumorigenesis and explore those scenarios which can explain the absence of somatic BRCA1 alterations while replicating all other disease statistics. Our results support the existence of a heterozygous phenotype of BRCA1 and suggest that the loss of one BRCA1 allele may suppress the fitness advantage caused by the inactivation of other tumor suppressor genes. This paper contributes to the mathematical investigation of breast tumorigenesis.

Breast cancer in the personal genomics era

Breast cancer is a heterogeneous disease with a complex etiology that develops from different cellular lineages, progresses along multiple molecular pathways, and demonstrates wide variability in response to treatment. The "standard of care" approach to breast cancer treatment in which all patients receive similar interventions is rapidly being replaced by personalized medicine, based on molecular characteristics of individual patients. Both inherited and somatic genomic variation is providing useful information for customizing treatment regimens for breast cancer to maximize efficacy and minimize adverse side effects. In this article, we review (1) hereditary breast cancer and current use of inherited susceptibility genes in patient management; (2) the potential of newly-identified breast cancer-susceptibility variants for improving risk assessment; (3) advantages and disadvantages of direct-to-consumer testing; (4) molecular characterization of sporadic breast cancer through immunohistochemistry and gene expression profiling and opportunities for personalized prognostics; and (5) pharmacogenomic influences on the effectiveness of current breast cancer treatments. Molecular genomics has the potential to revolutionize clinical practice and improve the lives of women with breast cancer.

Electronic health records and the management of women at high risk of hereditary breast and ovarian cancer

Currently, management strategies exist that can decrease the morbidity and mortality associated with having a BRCA1 or BRCA2 mutation. Unfortunately, the task of identifying these patients at high risk is a daunting challenge. This problem is intensified because Electronic Health Records (EHRs) today lack the functionality needed to identify these women and to manage those women once they have been identified. Numerous niche software programs have been developed to fill this gap. Unfortunately, these extremely valuable niche programs are prevented from being interoperable with the EHRs, on the premise that each EHR vendor will build their own programs. Effectively, in our efforts to adopt EHRs, we have lost sight of the fact that they can only have a major impact on quality of care if they contain structured data and if they interact with robust Clinical Decision Support (CDS) tools. We are at a cross roads in the development of the health care Information Technology infrastructure. We can choose a path where each EHR vendor develops each CDS module independently. Alternatively, we can choose a path where experts in each field develop external niche software modules that are interoperable with any EHR vendor. We believe that the modular approach to development of niche software programs that are interoperable with current EHRs will markedly increase the speed at which useful and functional EHRs that improve quality of care become a reality. Thus, in order to realize the benefits of CDS, we suggest vendors develop means to become interoperable with external modular niche programs.

Laypersons' responses to the communication of uncertainty regarding cancer risk estimates

OBJECTIVE

To explore laypersons' responses to the communication of uncertainty associated with individualized cancer risk estimates and to identify reasons for individual differences in these responses.

DESIGN

A qualitative study was conducted using focus groups. Participants were informed about a new colorectal cancer risk prediction model, and presented with hypothetical individualized risk estimates using presentation formats varying in expressed uncertainty (range v. point estimate). Semistructured interviews explored participants' responses to this information.

PARTICIPANTS AND SETTING

Eight focus groups were conducted with 48 adults aged 50 to 74 residing in 2 major US metropolitan areas, Chicago, IL and Washington, DC. Purposive sampling was used to recruit participants with a high school or greater education, some familiarity with information technology, and no personal or immediate family history of cancer.

RESULTS

Participants identified several sources of uncertainty regarding cancer risk estimates, including missing data, limitations in accuracy and source credibility, and conflicting information. In comparing presentation formats, most participants reported greater worry and perceived risk with the range than with the point estimate, consistent with the phenomenon of "ambiguity aversion.'' However, others reported the opposite effect or else indifference between formats. Reasons suggested by participants' responses included individual differences in optimism and motivations to reduce feelings of vulnerability and personal lack of control. Perceptions of source credibility and risk mutability emerged as potential mediating factors.

CONCLUSIONS

Laypersons' responses to the communication of uncertainty regarding cancer risk estimates differ, and include both heightened and diminished risk perceptions. These differences may be attributable to personality, cognitive, and motivational factors.

Cancer genetics service interest in women with a limited family history of breast cancer

Women with a limited family history of breast cancer may be interested in cancer genetics information although their objective risk of breast cancer may not indicate routine referral to cancer genetics services. This study examined factors related to interest and use of cancer genetics services in a community sample of women with a limited family history of breast cancer (N = 187) who had no previous contact with cancer genetics services. Participants provided demographic information and ratings of perceived risk, cancer distress, attitudes, and intentions to initiate cancer genetics services. Participants were given information about a cancer genetics clinic that served women having concerns about their breast cancer risk. Women were contacted within 6 weeks and 8 months following their study appointment. Six weeks following their study appointment, 25% of women had initiated cancer genetics services. Eight months following their study appointment, 18% of women reported having completed a cancer genetics service appointment. Baseline intentions independently predicted both initiation at 6 weeks and appointment at 8 months. Cancer distress was positively associated with cancer genetics service initiation and appointment. Results suggest that some women with a limited family history of breast cancer are interested in seeking out cancer genetics information. Women with a limited family history of breast cancer may benefit from the availability of cancer genetics information provided through primary healthcare settings.

CpG island tumor suppressor promoter methylation in non-BRCA-associated early mammary carcinogenesis

BACKGROUND

Only 5% of all breast cancers are the result of BRCA1/2 mutations. Methylation silencing of tumor suppressor genes is well described in sporadic breast cancer; however, its role in familial breast cancer is not known.

METHODS

CpG island promoter methylation was tested in the initial random periareolar fine-needle aspiration sample from 109 asymptomatic women at high risk for breast cancer. Promoter methylation targets included RARB (M3 and M4), ESR1, INK4a/ARF, BRCA1, PRA, PRB, RASSF1A, HIN-1, and CRBP1.

RESULTS

Although the overall frequency of CpG island promoter methylation events increased with age (P<0.0001), no specific methylation event was associated with age. In contrast, CpG island methylation of RARB M4 (P=0.051), INK4a/ARF (P=0.042), HIN-1 (P=0.044), and PRA (P=0.032), as well as the overall frequency of methylation events (P=0.004), was associated with abnormal Masood cytology. The association between promoter methylation and familial breast cancer was tested in 40 unaffected premenopausal women in our cohort who underwent BRCA1/2 mutation testing. Women with BRCA1/2 mutations had a low frequency of CpG island promoter methylation (15 of 15 women had <or=4 methylation events), whereas women without a mutation showed a high frequency of promoter methylation events (24 of 25 women had 5-8 methylation events; P<0.0001). Of women with a BRCA1/2 mutation, none showed methylation of HIN-1 and only 1 of 15 women showed CpG island methylation of RARB M4, INK4a/ARF, or PRB promoters.

CONCLUSIONS

This is the first evidence of CpG island methylation of tumor suppressor gene promoters in non-BRCA1/2 familial breast cancer.

Conceptual problems in laypersons' understanding of individualized cancer risk: a qualitative study

OBJECTIVE

To explore laypersons' understanding of individualized cancer risk estimates, and to identify conceptual problems that may limit this understanding.

BACKGROUND

Risk prediction models are increasingly used to provide people with information about their individual risk of cancer and other diseases. However, laypersons may have difficulty understanding individualized risk information, because of conceptual as well as computational problems.

DESIGN

A qualitative study was conducted using focus groups. Semi-structured interviews explored participants' understandings of the concept of risk, and their interpretations of a hypothetical individualized colorectal cancer risk estimate.

SETTING AND PARTICIPANTS

Eight focus groups were conducted with 48 adults aged 50-74 years residing in two major US metropolitan areas. Participants had high school or greater education, some familiarity with information technology, and no personal or family history of cancer.

RESULTS

Several important conceptual problems were identified. Most participants thought of risk not as a neutral statistical concept, but as signifying danger and emotional threat, and viewed cancer risk in terms of concrete risk factors rather than mathematical probabilities. Participants had difficulty acknowledging uncertainty implicit to the concept of risk, and judging the numerical significance of individualized risk estimates. The most challenging conceptual problems related to conflict between subjective and objective understandings of risk, and difficulties translating aggregate-level objective risk estimates to the individual level.

CONCLUSIONS

Several conceptual problems limit laypersons' understanding of individualized cancer risk information. These problems have implications for future research on health numeracy, and for the application of risk prediction models in clinical and public health settings.

Perspective: Prospective health care and the role of academic medicine: lead, follow, or get out of the way

The authors contend that the crisis facing the U.S. health care system is in large part a consequence of that system's disease-oriented, reactive, and sporadic approach to care, and they suggest that a prospective approach to health care, which emphasizes personalized medicine and strategic health planning, would be a more rational way to prevent disease and maximize health. During recent years, personalized, predictive, preventive, and participatory medicine--that is, prospective care--has been receiving increasing attention as a solution to the U.S. health care crisis. Advocacy has been mainly from industry, government, large employers, and private insurers. However, academic medicine, as a whole, has not played a leading role in this movement. The authors believe that academic medicine has the opportunity and responsibility to play a far greater role in the conception and development of better models to deliver health care. In doing so, it could lead the transformation of today's dysfunctional system of medical care to that of a prospective approach that emphasizes personalization, prediction, prevention, and patient participation. Absent contributing to improving how care is delivered, academic medicine's leadership in our nation's health will be bypassed.

A statistical model for the identification of genes governing the incidence of cancer with age

The cancer incidence increases with age. This epidemiological pattern of cancer incidence can be attributed to molecular and cellular processes of individual subjects. Also, the incidence of cancer with ages can be controlled by genes. Here we present a dynamic statistical model for explaining the epidemiological pattern of cancer incidence based on individual genes that regulate cancer formation and progression. We incorporate the mathematical equations of age-specific cancer incidence into a framework for functional mapping aimed at identifying quantitative trait loci (QTLs) for dynamic changes of a complex trait. The mathematical parameters that specify differences in the curve of cancer incidence among QTL genotypes are estimated within the context of maximum likelihood. The model provides testable quantitative hypotheses about the initiation and duration of genetic expression for QTLs involved in cancer progression. Computer simulation was used to examine the statistical behavior of the model. The model can be used as a tool for explaining the epidemiological pattern of cancer incidence.

Morphologically normal-appearing mammary epithelial cells obtained from high-risk women exhibit methylation silencing of INK4a/ARF

PURPOSE

p16(INK4a) has been appreciated as a key regulator of cell cycle progression and senescence. Cultured human mammary epithelial cells that lack p16(INK4a) activity have been shown to exhibit premalignant phenotypes, such as telomeric dysfunction, centrosomal dysfunction, a sustained stress response, and, most recently, a dysregulation of chromatin remodeling and DNA methylation. These data suggest that cells that lack p16(INK4a) activity would be at high risk for breast cancer development and may exhibit an increased frequency of DNA methylation events in early cancer.

EXPERIMENTAL DESIGN

To test this hypothesis, the frequencies of INK4a/ARF promoter hypermethylation, as well as four additional selected loci, were tested in the initial random periareolar fine needle aspiration samples from 86 asymptomatic women at high risk for development of breast cancer, stratified using the Masood cytology index.

RESULTS

INK4a/ARF promoter hypermethylation was observed throughout all early stages of intraepithelial neoplasia and, importantly, in morphologically normal-appearing mammary epithelial cells; 29 of 86 subjects showed INK4a/ARF promoter hypermethylation in at least one breast. Importantly, INK4a/ARF promoter hypermethylation was not associated with atypia, and the frequency of hypermethylation did not increase with increasing Masood cytology score. The frequency of INK4a/ARF promoter hypermethylation was associated with the combined frequency of promoter hypermethylation of retinoic acid receptor-beta2, estrogen receptor-alpha, and breast cancer-associated 1 genes (P = 0.001).

CONCLUSIONS

Because INK4a/ARF promoter hypermethylation does not increase with age but increases with the frequency of other methylation events, we predict that INK4a/ARF promoter hypermethylation may serve as a marker of global methylation dysregulation.

BRCA1 and BRCA2 genetic testing in Hispanic patients: mutation prevalence and evaluation of the BRCAPRO risk assessment model

PURPOSE

The BRCAPRO model, used to predict a family's likelihood of carrying a BRCA1 or BRCA2 mutation, was designed using mutation frequencies of white and Ashkenazi Jewish populations, and may not be applicable to other populations. BRCAPRO was recently validated in African Americans, although has yet to be examined in Hispanics. This retrospective study reports the mutation frequency and spectrum of BRCA1 and BRCA2 mutations in a Hispanic population and evaluates the BRCAPRO model in Hispanics.

PATIENTS AND METHODS

A descriptive analysis of mutation frequency and spectrum was performed for Hispanic patients who underwent BRCA1 and BRCA2 genetic testing at a single institution. For comparative analysis of the BRCAPRO risk model, Hispanic patients who underwent comprehensive analysis were compared with white controls using area under the receiver operating characteristic curves (AUROC).

RESULTS

Fourteen Hispanic individuals who underwent comprehensive analysis were identified to carry a mutation in BRCA1 or BRCA2 (17.9%; 95% CI, 10.2% to 28.3%) and seven individuals had a variant of uncertain significance (9.0%; 95% CI, 12.0% to 30.8%). A total of eight different mutations and three variants were observed within the entire Hispanic population. When evaluating the performance of the BRCAPRO model, the AUROC for Hispanics was 0.774 (95% CI, 0.63 to 0.90), compared with the AUROC of 0.770 (95% CI, 0.65 to 0.89) for whites.

CONCLUSION

Deleterious BRCA1 and BRCA2 mutations occur at considerable frequency within the Hispanic population, many of which have been identified previously in other ethnic populations. The BRCAPRO model appears to perform equally well in Hispanics as in whites.

Validity of models for predicting BRCA1 and BRCA2 mutations

BACKGROUND

Deleterious mutations of the BRCA1 and BRCA2 genes confer susceptibility to breast and ovarian cancer. At least 7 models for estimating the probabilities of having a mutation are used widely in clinical and scientific activities; however, the merits and limitations of these models are not fully understood.

OBJECTIVE

To systematically quantify the accuracy of the following publicly available models to predict mutation carrier status: BRCAPRO, family history assessment tool, Finnish, Myriad, National Cancer Institute, University of Pennsylvania, and Yale University.

DESIGN

Cross-sectional validation study, using model predictions and BRCA1 or BRCA2 mutation status of patients different from those used to develop the models.

SETTING

Multicenter study across Cancer Genetics Network participating centers.

PATIENTS

3 population-based samples of participants in research studies and 8 samples from genetic counseling clinics.

MEASUREMENTS

Discrimination between individuals testing positive for a mutation in BRCA1 or BRCA2 from those testing negative, as measured by the c-statistic, and sensitivity and specificity of model predictions.

RESULTS

The 7 models differ in their predictions. The better-performing models have a c-statistic around 80%. BRCAPRO has the largest c-statistic overall and in all but 2 patient subgroups, although the margin over other models is narrow in many strata. Outside of high-risk populations, all models have high false-negative and false-positive rates across a range of probability thresholds used to refer for mutation testing.

LIMITATION

Three recently published models were not included.

CONCLUSIONS

All models identify women who probably carry a deleterious mutation of BRCA1 or BRCA2 with adequate discrimination to support individualized genetic counseling, although discrimination varies across models and populations.

Prospective study of Outcomes in Sporadic versus Hereditary breast cancer (POSH): study protocol

Background

Young women presenting with breast cancer are more likely to have a genetic predisposition to the disease than breast cancer patients in general. A genetic predisposition is known to increase the risk of new primary breast (and other) cancers. It is unclear from the literature whether genetic status should be taken into consideration when planning adjuvant treatment in a young woman presenting with a first primary breast cancer. The primary aim of the POSH study is to establish whether genetic status influences the prognosis of primary breast cancer independently of known prognostic factors.

Methods/design

The study is a prospective cohort study recruiting 3,000 women aged 40 years or younger at breast cancer diagnosis; the recruiting period covers 1^st June 2001 to 31^st December 2007. Written informed consent is obtained at study entry. Family history and known epidemiological risk data are collected by questionnaire. Clinical information about diagnosis, treatment and clinical course is collected and blood is stored. Follow up data are collected annually after the first year. An additional recruitment category includes women aged 41 to 50 years who are found to be BRCA1 or BRCA2 gene carriers and were diagnosed with their first breast cancer during the study recruiting period.

Discussion

Power estimates were based on 10% of the cohort carrying a BRCA1 gene mutation. Preliminary BRCA1 and BRCA2 mutation analysis in a pilot set of study participants confirms we should have 97% power to detect a difference of 10% in event rates between gene carriers and sporadic young onset cases. Most of the recruited patients (>80%) receive an anthracycline containing adjuvant chemotherapy regimen making planned analyses more straightforward.

Risk assessment and genetic counseling for hereditary breast and ovarian cancer: recommendations of the National Society of Genetic Counselors

These cancer genetic counseling recommendations describe the medical, psychosocial and ethical implications of identifying at-risk individuals for hereditary breast and ovarian cancer (HBOC) through cancer risk assessment, with or without genetic susceptibility testing. They were developed by members of the Practice Issues Subcommittee of the National Society of Genetic Counselors' Familial Cancer Risk Counseling Special Interest Group. The information contained in this document is derived from extensive review of the current literature on cancer genetic risk assessment as well as the professional expertise of genetic counselors with significant experience in education and counseling regarding hereditary breast and ovarian cancer. Critical components of the process include the ascertainment of medical and family histories, determination and communication of cancer risk, assessment of risk perception, education regarding the genetics of HBOC, discussion of molecular testing for HBOC if appropriate (including benefits, risks and limitations) and any necessary follow-up. These recommendations do not dictate an exclusive course of management or guarantee a specific outcome. Moreover, they do not replace the professional judgment of a health care provider based on the clinical situation of a client.

Patient variables that predict atypical cytology by nipple duct lavage

BACKGROUND

Nipple duct lavage (NDL) may be useful for breast cancer risk stratification. Published guidelines recommend that women with a 5-year Gail risk >/=1.7% should consider undergoing lavage for any fluid-yielding ducts, but it is not known whether increased breast cancer risk or nipple fluid production predict lavage atypia.

METHODS

One hundred fifty women unselected for breast cancer risk underwent NDL with cannulation of all nipple aspirate fluid (NAF)-producing ducts and at least 1 dry duct. This resulted in 516 lavage samples. The rate of cytologic atypia was compared for NAF-positive ducts and NAF-negative ducts and for women with 5-year Gail risks >/=1.7% and <1.7%. Ducts from breasts with cancer (N = 113) were excluded from the analysis.

RESULTS

The cytologic atypia rate was similar for the 240 NAF-producing ducts (19%) and the 163 dry ducts (15%; P = .36). No significant differences were observed when atypia was categorized as mild (13% vs 10%; P = .63) or marked (6% vs 4%; P = .53). Among the 83 patients who were unaffected by breast cancer, atypia was diagnosed in 15 of 44 patients (34%) with a 5-year Gail risk <1.7% and in 11 of 39 patients (28%) with a 5-year Gail risk >/=1.7% (P = .74).

CONCLUSIONS

Neither NAF production nor 5-year Gail risk predicted lavage atypia. Limiting NDL to fluid-producing ducts in women with a 5-year Gail risk >/=1.7% significantly reduced the sensitivity of the test for population screening.

Effectiveness of the CRCAPRO program in identifying patients suspected for HNPCC

Subjects affected by hereditary non-polyposis colorectal cancer exhibit a high susceptibility to colon and extracolonic tumours, due to MMR gene defects. Revised Bethesda criteria are used to select patients as candidates for genetic tests. Recently, the CRCAPRO model has been developed, based on family history of colorectal and endometrial cancers. Our study aims to evaluate the reliability of CRCAPRO in identifying mutation carriers. We used the CRCAPRO program to evaluate carrier probability risk in 99 patients fulfilling Amsterdam or Bethesda guidelines. MLH1 and MSH2 were studied by direct sequencing in all the 99 patients, and the study of microsatellite instability and of MMR proteins expression was performed. Nine MLH1 and nine MSH2 germline mutations were identified. Five out of the nine patients with MLH1 mutation showed a CRCAPRO risk evaluation of less than 20%. The same happened for four out of nine patients with MSH2 mutation. Of the 17 patients with an estimated risk of more than 80%, only four harboured a mutation, all in the MSH2 gene. The highest risk calculated by the CRCAPRO system in the nine carriers of a MLH1 mutation has been 31.7%. In our experience, the CRCAPRO program sensitivity and specificity appears to be low but needs to be further evaluated in larger samples.

Incorporating medical interventions into carrier probability estimation for genetic counseling

Background

Mendelian models for predicting who may carry an inherited deleterious mutation of known disease genes based on family history are used in a variety of clinical and research activities. People presenting for genetic counseling are increasingly reporting risk-reducing medical interventions in their family histories because, recently, a slew of prophylactic interventions have become available for certain diseases. For example, oophorectomy reduces risk of breast and ovarian cancers, and is now increasingly being offered to women with family histories of breast and ovarian cancer. Mendelian models should account for medical interventions because interventions modify mutation penetrances and thus affect the carrier probability estimate.

Methods

We extend Mendelian models to account for medical interventions by accounting for post-intervention disease history through an extra factor that can be estimated from published studies of the effects of interventions. We apply our methods to incorporate oophorectomy into the BRCAPRO model, which predicts a woman's risk of carrying mutations in BRCA1 and BRCA2 based on her family history of breast and ovarian cancer. This new BRCAPRO is available for clinical use.

Results

We show that accounting for interventions undergone by family members can seriously affect the mutation carrier probability estimate, especially if the family member has lived many years post-intervention. We show that interventions have more impact on the carrier probability as the benefits of intervention differ more between carriers and non-carriers.

Conclusion

These findings imply that carrier probability estimates that do not account for medical interventions may be seriously misleading and could affect a clinician's recommendation about offering genetic testing. The BayesMendel software, which allows one to implement any Mendelian carrier probability model, has been extended to allow medical interventions, so future Mendelian models can easily account for interventions.

Hypermethylation of the Breast Cancer–Associated Gene 1 Promoter Does Not Predict Cytologic Atypia or Correlate with Surrogate End Points of Breast Cancer Risk

Mutation of the breast cancer-associated gene 1 (BRCA1) plays an important role in familial breast cancer. Although hypermethylation of the BRCA1 promoter has been observed in sporadic breast cancer, its exact role in breast cancer initiation and association with breast cancer risk is unknown. The frequency of BRCA1 promoter hypermethylation was tested in (a) 14 primary breast cancer biopsies and (b) the initial random periareolar fine-needle aspiration (RPFNA) cytologic samples obtained from 61 asymptomatic women who were at increased risk for breast cancer. BRCA1 promoter hypermethylation was assessed from nucleotide -150 to nucleotide +32 relative to the transcription start site. RPFNA specimens were stratified for cytologic atypia using the Masood cytology index. BRCA1 promoter hypermethylation was observed at similar frequency in nonproliferative (normal; Masood <or=10: 18%, 2 of 11), hyperplastic (Masood 11-13: 15%, 6 of 41), and atypical cytology (Masood 14-17: 22%, 4 of 18; P = 0.79). BRCA1 promoter hypermethylation was not associated with (a) family history of breast or ovarian cancer or (b) calculated Gail or BRCAPRO risk score. BRCA1 promoter hypermethylation was associated with (a) age (P = 0.028) and (b) the combined frequency of promoter hypermethylation of the retinoic acid receptor-beta2 (RARB) gene, estrogen receptor-alpha (ESR1) gene, and p16 (INK4A) gene (P = 0.003). These observations show that BRCA1 promoter hypermethylation (a) is not associated with breast cancer risk as measured by mathematical risk models and (b) does not predict mammary atypia in RPFNA cytologic samples obtained from high-risk women.

Breast Cancer Risk and Immune Responses in Healthy Women

PURPOSE/OBJECTIVES

To summarize the findings of objective and subjective breast cancer risk assessments and their association with psychological distress and immune responses in healthy women with a family history of breast cancer.

DATA SOURCES

Published articles and book chapters.

DATA SYNTHESIS

Healthy women with a family history of breast cancer have shown decreased immune responses (i.e., low natural killer cell activity and low Th1 cytokine production), exaggerated biophysiologic reactivity to stimuli, and increased psychological distress.

CONCLUSIONS

Objective and subjective breast cancer risk is associated with impaired immune responses and exaggerated biophysiologic responses in healthy women with a family history of breast cancer. Increased psychological distress can contribute further to negative immune responses. Additional studies are warranted to substantiate and extend the findings based on more comprehensive assessments of objective and subjective breast cancer risk.

IMPLICATIONS FOR NURSING

Biophysiologic assessment is a useful approach for nurses in early identification of women at risk for breast cancer and developing appropriate strategies to reduce the risk.

Personal care products that contain estrogens or xenoestrogens may increase breast cancer risk

Established models of breast cancer risk, such as the Gail model, do not account for patterns of the disease in women under the age of 35, especially in African Americans. With the possible exceptions of ionizing radiation or inheriting a known genetic mutation, most of the known risk factors for breast cancer are related to cumulative lifetime exposure to estrogens. Increased risk of breast cancer has been associated with earlier onset of menses or later age at menopause, nulliparity or late first parity, use of hormonal contraceptives or hormone replacement therapy, shorter lactation history, exposure to light at night, obesity, and regular ingestion of alcohol, all of which increase circulating levels of unbound estradiol. Among African Americans at all ages, use of hormone-containing personal care products (PCPs) is more common than among whites, as is premature appearance of secondary sexual characteristics among infants and toddlers. We hypothesize that the use of estrogen and other hormone-containing PCPs in young African American women accounts, in part, for their increased risk of breast cancer prior to menopause, by subjecting breast buds to elevated estrogen exposure during critical windows of vulnerability in utero and in early life. These early life and continuing exposures to estrogenic and xenoestrogenic agents may also contribute to the increased lethality of breast cancer in young women in general and in African American women of all ages. Public disclosure by manufacturers of proprietary hormonally active ingredients is required for this research to move forward.

Validation of a Self-Administered, Computerized Tool for Collecting and Displaying the Family History of Cancer

Purpose

A detailed family history is important for cancer risk assessment, but obtaining it is time consuming and infrequently accomplished in practice. The Genetic Risk Easy Assessment Tool (GREAT) conducts a computer-administered family history interview and immediately generates a pedigree diagram in digital form. The purpose of this study was to validate family cancer histories produced by patients using the computer tool in comparison with pedigrees made by genetic counselors.

Methods

Patients scheduled for genetics consultation recorded their family histories using the GREAT, separate from their genetic counseling session. The presence of each relative; presence, type, and age at diagnosis of cancers; and cancer geneticist's risk assessment were compared for 120 pairs of pedigrees produced by counselors versus computer tool.

Results

The automated telephone interview took a mean of 33.5 minutes and was highly acceptable to respondents. Ninety-four percent of first-degree relatives, 67% of second-degree relatives, and 38% of third-degree relatives were identical on paired pedigrees; computer-generated pedigrees included additional relatives. Sixty-three percent of all cancers were identified by both family histories, with 90% agreement on the type of cancer. There was very good agreement (κ = 0.70; correlation = 0.77) between the geneticist's breast cancer risk assessments based on computer versus counselors' pedigrees. In a subsample of 61 users, test-retest reliability for the computer-administered questionnaire was high (φ = 0.94 for cancers in first-degree and φ = 0.91 in second-degree relatives).

Conclusion

The GREAT computer-administered questionnaire provides an acceptable, reliable, and valid way of collecting an unverified but extensive family history of cancer and displaying it as a pedigree, in an entirely automated process.

Mammographic density correlation with Gail model breast cancer risk estimates and component risk factors

BACKGROUND

The Gail model is a validated breast cancer risk assessment tool that is primarily based on nonmodifiable breast cancer risk factors. Conversely, mammographic breast density is strongly correlated with breast cancer risk and responds to risk-modifying interventions. The purpose of our study was to correlate mammographic density with breast cancer risk as calculated by the Gail model and to examine the relative association of each of the model covariates to mammographic density.

METHODS

The study included 99 participants of the National Surgical Breast and Bowel Project P-1 trial, ages 36 to 74 years, all of whom had a mammogram and Gail model risk estimates done upon trial entry. Baseline mammograms were retrieved and digitized, and mammographic density was assessed by both subjective and computer-assisted objective measures.

RESULTS

Mammographic density was 2-fold higher in women with a >15% lifetime risk of breast cancer compared with those with <15% risk, by all density assessment methods. This was equivalent to a 3% to 6% increase in density per 10% increase in risk. Gail model covariates that measured benign or premalignant breast tissue changes accounted for the majority (41%) of the relationship with increased mammographic density. Seven percent of density was not explained by risk factors included in the Gail model.

CONCLUSIONS

The Gail model does not fully account for the association between breast density and calculated breast cancer risk. Because mammographic density is a modifiable marker, development of a breast cancer risk assessment tool that includes mammographic density could be beneficial for assessing individual risk.

Evaluation of models to predict BRCA germline mutations

The selection of candidates for BRCA germline mutation testing is an important clinical issue yet it remains a significant challenge. A number of risk prediction models have been developed to assist in pretest counselling. We have evaluated the performance and the inter-rater reliability of four of these models (BRCAPRO, Manchester, Penn and the Myriad-Frank). The four risk assessment models were applied to 380 pedigrees of families who had undergone BRCA1/2 mutation analysis. Sensitivity, specificity, positive and negative predictive values, likelihood ratios and area under the receiver operator characteristic (ROC) curve were calculated for each model. Using a greater than 10% probability threshold, the likelihood that a BRCA test result was positive in a mutation carrier compared to the likelihood that the same result would be expected in an individual without a BRCA mutation was 2.10 (95% confidence interval (CI) 1.66–2.67) for Penn, 1.74 (95% CI 1.48–2.04) for Myriad, 1.35 (95% CI 1.19–1.53) for Manchester and 1.68 (95% CI 1.39–2.03) for BRCAPRO. Application of these models, therefore, did not rule in BRCA mutation carrier status. Similar trends were observed for separate BRCA1/2 performance measures except BRCA2 assessment in the Penn model where the positive likelihood ratio was 5.93. The area under the ROC curve for each model was close to 0.75. In conclusion, the four models had very little impact on the pre-test probability of disease; there were significant clinical barriers to using some models and risk estimates varied between experts. Use of models for predicting BRCA mutation status is not currently justified for populations such as that evaluated in the current study.

Prediction of germline mutations and cancer risk in the Lynch syndrome

CONTEXT

Identifying families at high risk for the Lynch syndrome (ie, hereditary nonpolyposis colorectal cancer) is critical for both genetic counseling and cancer prevention. Current clinical guidelines are effective but limited by applicability and cost.

OBJECTIVE

To develop and validate a genetic counseling and risk prediction tool that estimates the probability of carrying a deleterious mutation in mismatch repair genes MLH1, MSH2, or MSH6 and the probability of developing colorectal or endometrial cancer.

DESIGN, SETTING, AND PATIENTS

External validation of the MMRpro model was conducted on 279 individuals from 226 clinic-based families in the United States, Canada, and Australia (referred between 1993-2005) by comparing model predictions with results of highly sensitive germline mutation detection techniques. MMRpro models the autosomal dominant inheritance of mismatch repair mutations, with parameters based on meta-analyses of the penetrance and prevalence of mutations and of the predictive values of tumor characteristics. The model's prediction is tailored to each individual's detailed family history information on colorectal and endometrial cancer and to tumor characteristics including microsatellite instability.

MAIN OUTCOME MEASURE

Ability of MMRpro to correctly predict mutation carrier status, as measured by operating characteristics, calibration, and overall accuracy.

RESULTS

In the independent validation, MMRpro provided a concordance index of 0.83 (95% confidence interval, 0.78-0.88) and a ratio of observed to predicted cases of 0.94 (95% confidence interval, 0.84-1.05). This results in higher accuracy than existing alternatives and current clinical guidelines.

CONCLUSIONS

MMRpro is a broadly applicable, accurate prediction model that can contribute to current screening and genetic counseling practices in a high-risk population. It is more sensitive and more specific than existing clinical guidelines for identifying individuals who may benefit from MMR germline testing. It is applicable to individuals for whom tumor samples are not available and to individuals in whom germline testing finds no mutation.

Circulating MMP2 and MMP9 in breast cancer -- potential role in classification of patients into low risk, high risk, benign disease and breast cancer categories

Matrix metalloproteinase (MMP) 2 and 9 are involved in cancer invasion and metastasis, and increased levels occur in serum and plasma of breast cancer (BC) patients. It is, however, unclear whether changes in serum levels can be exploited for early detection or classification of patients into different risk/disease categories. In our study, we measured concentration and activity of MMP2/9 in sera of 345 donors classified as low risk (Gail score <1.7), high risk (HR) (Gail score > or =1.7), benign disease or BC. Kruskal-Wallis and Mann-Whitney nonparametric tests showed that total-MMP2 concentration is higher in HR compared to control (p = 0.012), benign (p = 0.001) and cancer (p = 0.007). Active MMP2 (aMMP2) concentration is higher in control than benign and cancer (p < 0.001, respectively). Total and aMMP9 concentrations are higher in cancer than benign (p < 0.001, p = 0.002, respectively). Total-MMP2 and total-MMP9 activities are lower in control than benign (p < 0.001, p = 0.002, respectively) and cancer (p < 0.001, respectively). Total-MMP2 and MMP9 activities are also higher in cancer than benign (p = 0.004, p < 0.001) and HR (p = 0.008, p = 0.007, respectively). These results were not affected by age or inclusion/exclusion of donors with noninvasive cancer or atypical hyperplasia. Linear discriminant analysis revealed that HR donors are characterized by lower total-MMP2 and higher aMMP2. Overall group classification accuracy was 64.5%. Independent validation based on the leave-one-out cross validation approach gave an overall classification of 63%. Our study provides evidence supporting the potential role of serum MMP2/9 as biomarkers for breast disease classification.

Prospective screening study of 0.5 Tesla dedicated magnetic resonance imaging for the detection of breast cancer in young, high-risk women

Background

Evidence-based screening guidelines are needed for women under 40 with a family history of breast cancer, a BRCA1 or BRCA2 mutation, or other risk factors. An accurate assessment of breast cancer risk is required to balance the benefits and risks of surveillance, yet published studies have used narrow risk assessment schemata for enrollment. Breast density limits the sensitivity of film-screen mammography but is not thought to pose a limitation to MRI, however the utility of MRI surveillance has not been specifically examined before in women with dense breasts. Also, all MRI surveillance studies yet reported have used high strength magnets that may not be practical for dedicated imaging in many breast centers. Medium strength 0.5 Tesla MRI may provide an alternative economic option for surveillance.

Methods

We conducted a prospective, nonrandomized pilot study of 30 women age 25–49 years with dense breasts evaluating the addition of 0.5 Tesla MRI to conventional screening. All participants had a high quantitative breast cancer risk, defined as ≥ 3.5% over the next 5 years per the Gail or BRCAPRO models, and/or a known BRCA1 or BRCA2 germline mutation.

Results

The average age at enrollment was 41.4 years and the average 5-year risk was 4.8%. Twenty-two subjects had BIRADS category 1 or 2 breast MRIs (negative or probably benign), whereas no category 4 or 5 MRIs (possibly or probably malignant) were observed. Eight subjects had BIRADS 3 results, identifying lesions that were "probably benign", yet prompting further evaluation. One of these subjects was diagnosed with a stage T1aN0M0 invasive ductal carcinoma, and later determined to be a BRCA1 mutation carrier.

Conclusion

Using medium-strength MRI we were able to detect 1 early breast tumor that was mammographically undetectable among 30 young high-risk women with dense breasts. These results support the concept that breast MRI can enhance surveillance for young high-risk women with dense breasts, and further suggest that a medium-strength instrument is sufficient for this application. For the first time, we demonstrate the use of quantitative breast cancer risk assessment via a combination of the Gail and BRCAPRO models for enrollment in a screening trial.

Breast Cancer Risk Estimates for Relatives of White and African American Women With Breast Cancer in the Women's Contraceptive and Reproductive Experiences Study

Purpose

Family history is a well-recognized risk factor for breast cancer. Familial aggregation and segregation analyses have estimated breast cancer risk based on family history primarily for white women; such information is limited for African American (AA) women. The purpose of this report is to update breast cancer risk estimates associated with a family history of breast cancer for white and AA women.

Methods

We used family cancer history from 2,676 white and 1,525 AA women with breast cancer (probands) in the population-based National Institute of Child Health and Human Development's Women's Contraceptive and Reproductive Experiences (CARE) Study to estimate age-specific breast cancer risks in their first degree adult female relatives. Cumulative hazard curves were calculated for relatives of all probands using Cox proportional hazards models, and were stratified by the proband's race and age at diagnosis and number of relatives affected.

Results

Breast cancer risks for white and AA women with a family history of the disease are similar through age 49 years, but diverge afterwards, with higher risks by age 79 in white women than in AA women (17.5% [SE, 0.9%] v 12.2% [SE, 1.1%]; P < .001). These risks increase as the number of affected first degree relatives increases, reaching 25.2% (SE, 3.4%) and 16.9% (SE, 4.0%) in white and AA women with more than one affected relative, respectively (P = .3).

Conclusion

We found age-related racial differences in breast cancer risk in women with a family history of breast cancer and have updated risk estimates for white and AA women for clinical use.

Linkage of a pedigree drawing program and database to a program for determining BRCA mutation carrier probability

An export module was developed for transferring primary relational pedigree data directly from a widely used pedigree program and relational database to the BRCAPRO program for calculation of BRCA gene mutation probability estimation.