Validation of a breast cancer risk assessment model in women with a positive family history

Risk prediction models for familial breast cancer

A positive family history of breast cancer, reflecting genetic susceptibility, is one of the strongest risk factors for the disease. A number of breast cancer susceptibility genes have been identified to date, with the most important being BRCA1 and BRCA2. Risk prediction models can be used to identify individuals likely to carry BRCA1 and BRCA2 mutations and individuals at high risk of developing the disease. This information can then be used to target genetic testing, screening and interventions more effectively. In this article, the authors review the risk models that have been developed for familial breast cancer and discuss their applicability, strengths and weaknesses, and present examples of classifying women into risk categories according to the predictions by the various models. The review concludes with a discussion of the ways in which risk models could be improved in the immediate- and long-term future.

Validation of a tool for identifying women at high risk for hereditary breast cancer in population-based screening

BACKGROUND

Recent scientific advances provide the opportunity to identify women in the general population at increased breast cancer risk and to offer effective early detection and disease prevention interventions.

METHODS

A pedigree assessment tool (PAT) was designed to identify women in primary care settings who are at increased risk for hereditary breast cancer, including potential BRCA mutation carriers. The PAT is a simple point-scoring system based on family cancer history with points weighted to account for features associated with a higher probability that a BRCA mutation is present. The ability of the PAT and the Gail model to accurately identify potential BRCA mutation carriers in 3,906 women without a personal history of breast cancer presenting for a screening mammogram at a community hospital was tested.

RESULTS

Eighty-six (2.2%) women had a family history indicative of a high probability (>10%) that a BRCA mutation was present within the family. The PAT performed better than the Gail model in correctly assigning women to the "high BRCA probability" cohort. The area under the receiver operating characteristic (ROC) curve for the PAT was 0.9625 compared with 0.389 and 0.5861 for the Gail model 5-year and lifetime risk estimates, respectively. At the optimal threshold score, the PAT performed with 100% sensitivity and 93% specificity.

CONCLUSIONS

The PAT is a simple and accurate tool for identifying women at risk for the hereditary breast cancer syndromes that can be employed as part of a comprehensive breast cancer risk-screening strategy in the primary care setting.

Coping with appraised breast cancer risk among women with family histories of breast cancer

This descriptive correlational study was based on Neuman's Systems Model and was designed to examine how women with family histories of breast cancer appraise and cope with breast cancer risk. Ninety percent of 209 women in the sample appraised their degree of breast cancer threat as moderate or high. Women with high degrees of appraised risk had low breast cancer risk scores, while women with moderate degrees of appraised risk had higher risk scores. The most common and effective coping modes used were confrontive, optimistic, and early detection behaviors. Over 75% of women either did not use evasive, emotive, palliative, and fatalistic modes of coping, or rated them as ineffective. Canonical correlation analyses revealed five different patterns of appraisal and coping behaviors and lent support to the premise that the type of coping behaviors used varies with how breast cancer risk is appraised.

Ductal lavage for breast cancer risk assessment

Ductal lavage is a minimally-invasive procedure that permits sampling of breast ductal fluids for cytopathologic analysis. The technique is performed with topical anesthesia and involves cannulation of any fluid-yielding nipple orifice with a specially-designed catheter for lavage and aspiration of the ductal system. The procedure is used for women who have clinical evidence of increased breast cancer risk; if atypia is detected, it may strengthen a woman's interest in committing to a risk-reducing strategy or a chemoprevention trial. The technology also is being used as a tool in ongoing translational research studies.

Validation of a decision model for preventive pharmacological strategies in postmenopausal women

BACKGROUND

Benefits and risks of a combined hormone replacement therapy (HRT) based on randomized clinical trial emerged on various disease endpoints in 2002. The Women's Health Initiative (WHI) provides an important health answer for healthy postmenopausal women, such as do not use combined HRT to prevent chronic disease, because of the elevated risk of coronary artery disease (CHD), stroke and venous thromboembolism. In March 2004, the NIH stopped the drugs in the estrogen-alone trial after finding an increase risk of stroke and no effect, neither an increase or a decrease, on risk of CHD after an average of 7 years in the trial. On the other hand, raloxifene, which does not seem to significantly increase the risk of cardiovascular events and could retain skeletal benefits without stimulating endometrial and breast tissue, requires decision-makers since no current data on these disease clinical endpoints have been published.

OBJECTIVE

To construct a multi-disease model based on patient-specific risk factor profiles, and to validate the multi-disease model with several tools of internal and external validities.

METHODS

A Markov state model was developed. The risks of these various diseases (including coronary artery disease, stroke, hip fracture and breast cancer) are derived from published hazards proportional models which take into account significant risk factors. Canadian-specific rates and data sources for these transition probabilities are derived from published studies and Canadian Health Statistics. The validation of our model were based on several tools of internal and external validities, such as Canadian life expectancy, population-based incidence rate of diseases, clinical trials and other published life expectancy models.

RESULTS

First, presumably, small changes in the lifetime probability of dying support the hypothesis that the disease states operate in a largely independent fashion. For instance, the difference in the probability of dying from a particular disease by the complete elimination of a selected disease, such as CHD, stroke or breast cancer, ranged from 0.2 to 2.2% of difference in the lifetime probability of dying of these diseases. Second, we demonstrated that the model adequately predicted the Canadian population lifetable and disease-incidence rates from population-based data among women from 45 to 75 years old. The predictions of the model were cross-checked from non-source data, such as predicted outcomes versus observed outcomes from results of clinical trials. Predicted relative risks of CHD event, breast cancer and hip fracture fell in the reported 95% confidence interval of clinical trials. Finally, predicted treatment benefits are comparable with those of published life expectancy models.

CONCLUSIONS

The results of the study demonstrated that this multi-disease model, including coronary artery disease, stroke, hip fracture and breast cancer, is a valid model to predict the impact on life expectancy or number of events prevented for preventive pharmacological interventions.

Breast Cancer in African‐American Women

African-American women face a lower risk of being diagnosed with breast cancer as compared to Caucasian-American women, yet they paradoxically face an increased breast cancer mortality hazard. An increased incidence rate for early-onset disease has also been documented. This manuscript review summarizes the socioeconomic, environmental, genetic, and possible primary tumor biologic factors that may explain these disparities.

Ductal Lavage and Risk Assessment of Breast Cancer

Following recent advances in breast cancer chemoprevention, much emphasis has been placed on risk assessment to evaluate whether women at increased risk for developing breast cancer should proceed with breast cancer risk reduction strategies. The currently available risk-reduction approaches include screening, chemoprevention, and preventive surgeries. Breast cancer arises from the epithelial linings of the ductal system, and it is believed that hyperplasia and atypical hyperplasia represent early changes in the breast carcinogenesis process. The ductal lavage procedure offers a minimally invasive method to obtain breast epithelial cells from the ductal system for cytopathologic analysis to provide individualized risk assessment. This paper reviews breast cancer risk factors, with an emphasis on cytological atypia and the role of ductal lavage in breast cancer risk assessment.

Cancer genetics in primary care

The cloning of two major breast cancer susceptibility genes, BRCA1 and BRCA2, in 1994 and 1995 and the subsequent development of commercial genetic testing has brought hereditary cancer genetics into the public eye. In addition to DNA-based genetic testing, new strategies and treatments have been developed to provide accurate assessment of cancer risk and to reduce the chances of cancer developing in the future. This increasing scientific and public attention has prompted some cancer patients and their families to find out whether they "have the cancer gene" and has placed more responsibility on primary care clinicians to identify people who should be referred for specialized services of hereditary cancer genetics.

Common hereditary cancer syndromes

OBJECTIVES

To review cancer risk assessment and counseling, hereditary cancer syndrome risk factors, indicators for cancer predisposition testing, and interpretation of genetic test results.

DATA SOURCES

Research studies, review articles, and authors' experience.

CONCLUSION

Approximately 10% of those with a diagnosis of cancer may have a hereditary predisposition. In many cases genetic testing for susceptibility genes may be available. Knowledge of the results of genetic testing can be helpful when developing a plan for cancer prevention and early detection, and addressing concerns associated with genetic testing with the individual and family.

IMPLICATIONS FOR NURSING PRACTICE

Nurses need to know how to access genetic resources and to identify, evaluate, and care for patients and families at risk of or diagnosed with common hereditary cancer syndromes.

Comparing breast cancer risk between lesbians and their heterosexual sisters

PURPOSE

The purpose of this study was to explore the similarities and differences between lesbians and their heterosexual sisters in the established risks for developing breast cancer.

METHODS

The design for this study was a matched (lesbian with heterosexual sister) cross-sectional, mail-back, anonymous survey. We distributed the surveys throughout the state of California to English-speaking women who identified themselves as lesbians, age 40 and older, and their sisters. Using the modified Gail Breast Cancer Risk model as well as other well-established factors associated with the development of breast cancer, we compared the breast cancer risk potential for 324 sister pairs (N = 648). Data were analyzed using paired t-tests, analysis of covariance (ANCOVA), McNemar's chi(2), or the Bowker statistic, as appropriate for the level of data.

MAIN FINDINGS

The lesbians had significantly higher 5-year (p <.0001) and lifetime (p =.001) risk for developing breast cancer. The reasons for lesbians' predicted rate of breast cancer were most likely their higher scores on all pregnancy-related variables and the relatively high number of breast biopsies they reported. The lesbians had used birth control pills less (p <. 0001), had significantly fewer pregnancies (p <.0001), children (p <.0001), abortions (p <.0001), and miscarriages (p <.0001) as well as significantly more breast biopsies (p =.02) than did their heterosexual sisters.

CONCLUSIONS

A lesbian who comes out to her clinician is relying on the clinician to be informed and be open to discuss her life. When a lesbian has a lump or a suspicious mammogram, she needs her clinician to advocate for her within the health care system because she is at higher risk for having cancer than a heterosexual woman.

Current comprehensive assessment and management of women at increased risk for breast cancer

The potential for reducing the risk of breast cancer through selective estrogen receptor modulators, aromatase inhibitors, and surgery has generated interest in the use of quantitative models of risk assessment. With the addition of ductal lavage cytology to traditional epidemiologic risk factors, a discovery of cellular atypia can result in refinement of assigned risk values, while simultaneously optimizing patient selection for selective estrogen receptor modulators utilization. In view of increasing complexity in this arena, a Risk Assessment Working Group was formed to outline management strategies for the patient at an elevated risk for the development of breast cancer. No longer a statistical exercise, quantitative risk assessment is part of basic breast care and comprehensive management includes a discussion of the following: ductal lavage for improved risk stratification, multiple options for risk reduction, and high risk surveillance strategies that might incorporate investigational imaging protocols.

Risk models used to counsel women for breast and ovarian cancer: a guide for clinicians

Advances in the identification and treatment of breast and ovarian cancer have lead to a need for reliable estimates of susceptibility risk associated with these two cancers. These estimates may be used in clinical settings to identify individuals at increased risk of developing disease or of being a carrier of a disease susceptibility allele. Accurate assessment of these probabilities is important given the potential implications for medical decision-making including the identification of patients who might benefit from preventive measures, genetic counseling or from entry into clinical trials. A wide range of empirical and statistical models has been proposed, particularly for breast cancer risk prediction, including those that utilize logistic regression or Bayesian modeling. The specific data used to create the various risk models also varies and may include molecular, epidemiologic, or clinical information. This overview presents definitions of risk used in clinical oncology as well as several of the more frequently used methods of risk estimation for breast and ovarian cancer. In addition, the means by which different methods are able to provide a measure of error or uncertainty associated with a given risk estimate will be discussed.

Breast carcinoma screening and risk perception among women at increased risk for breast carcinoma

BACKGROUND

The Gail model is validated to estimate breast carcinoma risk. The authors assessed the association of Gail risk scores with screening and cancer risk perception.

METHODS

Using the 2000 National Health Interview Survey, the authors studied women ages 41-70 without a cancer history. Gail scores > or = 1.66% defined increased risk. The authors used logistic regression to assess associations between breast carcinoma risk and previous and recent (< or = 1 year) mammography and clinical breast examination (CBE).

RESULTS

Of 6410 women, 15.7% had increased risk. High-risk women more frequently reported previous mammograms (94% vs. 85%; P < 0.0001), previous CBE (93% vs. 88%; P < 0.0001), recent mammograms (70% vs. 54%; P < 0.0001), recent CBE (71% vs. 61%; P < 0.0001), and high cancer risk perception (20% vs. 9%; P < 0.0001). However, 30% of high-risk women had not received a recent mammogram. After adjustment for sociodemographic factors, access to care factors, and cancer risk perception, high-risk women remained more likely to have received recent mammography (adjusted odds ratio [OR], 1.45, 95% confidence interval [95% CI], 1.19-1.77), recent CBE (OR, 1.32; 95% CI, 1.08-1.61]), and previous mammography than average-risk women. The authors observed an interaction between risk and age, with women ages 41-49 years more frequently reporting previous mammography (OR, 4.79; 95% CI, 1.55-4.81) than average-risk, same-age women. For women age > or = 50 years, the odds of previous mammography were similar regardless of risk.

CONCLUSIONS

In a nationally representative sample, 15.7% of women had increased breast carcinoma risk using the Gail model. High-risk women perceived higher cancer risk and more often received screening. However, nearly one in three high-risk women did not receive recent screening and most of these women did not perceive increased risk.

Should Tamoxifen Be Used in Breast Cancer Prevention?

Breast cancer is the most commonly diagnosed cancer in women. The risk of developing breast cancer can be lowered by maintaining a healthy bodyweight and avoiding long-term use of combined estrogen and progestogen replacement after menopause. However, many women are at an increased risk of developing breast cancer secondary to age, early menarche, a family history of breast cancer or a personal history of benign breast disease. These women may now be offered tamoxifen as a chemoprevention therapy. Five years of tamoxifen treatment results in a reduction in the relative risk of developing estrogen receptor-positive breast cancer of 48%. This benefit outweighs the risk of tamoxifen-related adverse events for many healthy women. However, the benefit-risk ratio of tamoxifen chemoprevention varies for individual women. The randomized clinical trials evaluating standard-dose tamoxifen versus placebo as chemoprevention therapy are reviewed and analyzed to determine which particular women are most likely to benefit and least likely to experience a tamoxifen-related adverse event. Tamoxifen decreases the risk of breast cancer associated with aging, having a first-degree relative with disease, and a personal diagnosis of atypical ductal hyperplasia or lobular carcinoma in situ. Women who have had a hysterectomy and are at low risk of a thromboembolic event have a decreased risk of adverse effects associated with tamoxifen therapy. The strengths and weaknesses of the Gail model (frequently used to assess an individual's risk of developing invasive breast cancer over the next 5 years) are highlighted. A method for assessing the benefit-risk ratio for an individual woman is presented. Alternative breast cancer chemoprevention strategies are considered, including the use of aromatase inhibitors. This article discusses the pros and cons of these various preventive therapies and concludes that at this time, tamoxifen remains the gold standard for breast cancer prevention.

The Impact of a Family History of Breast Cancer on Screening Practices and Attitudes in Low-Income, Rural, African American Women

BACKGROUND

Women with a family history of breast cancer are at increased risk for developing cancer and, therefore, might be expected to engage in early detection practices more actively than women without a family history. Alternatively, women with a family history may avoid thinking about cancer and have attitudes and practices that do not promote early detection.

METHODS

This study examined breast cancer attitudes and practices among African American women aged >or=50 who had not had a mammogram in the last 2 years.

RESULTS

Phone survey data from 320 female clients of low-income, rural primary care clinics (91% African American) indicated that 15% self-reported a family history of breast cancer (FH(+)). Half of the FH(+) women did not know their relative risk of developing breast cancer. Of those providing a risk estimate, 67% perceived themselves at low risk compared with other women their age. Perceived relative risk was comparable between FH(+) and FH(-) women. Further, FH(+) women did not indicate greater worry about breast cancer, nor did they have more accurate knowledge of mammography recommendations than FH(-) women. Two thirds of FH(+) women had never had a mammogram. Monthly breast self-examination did not differ between FH(+) and FH(-) women.

CONCLUSIONS

Thus, neither knowledge of a positive family history nor perceived relative risk of breast cancer was associated with either increased or decreased early detection practices among these low-income, rural, African American women who have underused mammography. Furthermore, a substantial proportion of FH(+) women had not ever participated in screening mammography. Interventions to increase mammography rates in this population of underusers are indicated.

Estimation of individualized probabilities of developing breast cancer for Japanese women

BACKGROUND

Projecting individualized probabilities of developing breast cancer is needed for counseling and chemoprevention for Japanese women, in whom breast cancer incidence has been rapidly increasing.

METHODS

We calculated individualized probabilities of developing breast cancer within 10-20 years and until life expectancy for Japanese women by multiplying the relative risk for each risk factor combination by the cumulative risk for the reference group. The risk factors used were age at menarche, age at first delivery, family history of breast cancer, and body mass index (BMI) (in post-menopausal women). The relative risk by menopausal status for each risk factor combination was estimated from a case control study conducted at Osaka Medical Center for Cancer and Cardiovascular Diseases (OMCC), Japan. The cumulative risk of breast cancer for the reference group within 10-20 years and until life expectancy was estimated to divide the corresponding cumulative risk for Japanese women by the weighted average of the relative risk. The weight is an expected proportion of those who have each risk factor combination among the general population. The cumulative risk for Japanese women was estimated using a data file from the Osaka Cancer Registry (OCR).

RESULTS

We obtained cumulative risks for any age women within a certain range according to various risk factor combinations by menopausal state. For example, the highest risk group had about a 5 times higher risk probability of developing breast cancer than the general population at initial age 40, within 10-20 years, and until life expectancy.

CONCLUSION

The cumulative risk of breast cancer varied according to individuals' risk factors among Japanese women. The availability of concrete individualized risk estimation figures will be of use to health care providers in encouraging Japanese women to seek counseling and to adopt self-control of body weight as a primary preventive measure, as well as to have breast cancer screening.

Management of the high-risk patient

Comprehensive breast cancer risk management is a practical tool that can now be regarded as a necessary clinical component of women's health. Risk assessment is the starting point for counseling women about risk, and it facilitates rational decision-making about prophylactic surgery, initiation of screening at an early age, and initiating preventive interventions. The availability of risk assessment models permit rapid risk calculation during routine clinical encounters, and risk profiles can be easily updated at subsequent clinical visits. Clinicians can now incorporate risk assessment and management into their routine screening and health maintenance appointments. Additional prospective clinical trials should be conducted to define the optimal use of existing management strategies, develop refined risk assessment instruments that incorporate additional risk-factor information, and evaluate populations for whom validated risk-assessment approaches do not yet exist.

Reproductive factors and familial predisposition for breast cancer by age 50 years. A case-control-family study for assessing main effects and possible gene-environment interaction

BACKGROUND

The effect of environmental/lifestyle factors on breast cancer risk may be modified by genetic predisposition.

METHODS

In a population-based case-control-family study performed in Germany including 706 cases by age 50 years, 1381 population, and 252 sister controls, we investigated main effects for environmental/lifestyle factors and genetic susceptibility and gene-environment interaction (G x E). Different surrogate measures for genetic predisposition using pedigree information were used: first-degree family history of breast or ovarian cancer; and gene carrier probability using a genetic model based on rare dominant genes. Possible G x E interaction was studied by (1) logistic regression using cases and population controls including an interaction term; (2) comparing results using sister controls and population controls; (3) case-only analysis with logistic regression and (4) a mixture logistic model.

RESULTS

Familial predisposition showed the strongest main effect and the estimated gene carrier probability gave the best fit. High parity and longer duration of breastfeeding reduced breast cancer risk significantly, a history of abortions increased risk and age at menarche showed no significant effect. We found significant G x E interaction between parity and genetic susceptibility using different surrogate measures. In women most likely to have a high genetic susceptibility, high parity was less protective. Later age at menarche was protective in women with a positive family history. No evidence for G x E interaction was found for breastfeeding and abortion.

CONCLUSIONS

These findings corroborate results from other studies and provide further evidence that the magnitude of protection from parity is reduced in women most likely to have a genetic risk in spite of the limitations of using surrogate genetic measures.

Evidence-based management options for women at increased breast/ovarian cancer risk

Recent developments in our ability to predict breast cancer risk necessitates primary care physicians learn to evaluate breast cancer risk and its importance in shaping decisions concerning surveillance and risk reduction measures. This article reviews the current opinion on risk assessment and management of women with an increased risk of breast/ovarian cancer. Management options are given for women at slightly, moderately and highly elevated breast cancer risk, as well as for BRCA1/2 carriers, based on currently available evidence.

Breast cancer risk assessment models: applicability to African-American women

BACKGROUND

Mortality rates are higher among African-American women with breast cancer than they are among white women. This population subset can benefit from available risk reduction strategies. Optimal public health gains from chemoprevention strategies depend on the ability to assess accurately the risk for the individual. However, it is not known if existing breast cancer prediction models are accurate predictors of the disease among African-American women.

METHODS

Literature was reviewed for breast cancer risk prediction models and their validation studies. Reported data were also reviewed regarding the strength of established breast cancer risk factors for African-American women.

RESULTS

The two currently accepted breast cancer risk assessment models, the Gail Model and the Claus Model, were designed primarily to provide risk assessments for white women. Neither model has been validated in African-American women. Reported data are inconsistent regarding the prevalence and strength of risk factors included in these models.

CONCLUSIONS

Efforts should be made to validate existing risk assessment models in African-American women and future research should be directed at the identification of more reliable risk assessment features.

Ductal lavage for breast cancer risk assessment

BACKGROUND

Effective chemoprevention is available for breast cancer, but it is associated with the potential for life-threatening adverse events. Accurate identification of women facing increased risk of breast cancer is therefore essential. Atypical hyperplasia is a histopathologic pattern that has been consistently associated with an elevated future risk of breast cancer.

METHODS

The literature was reviewed to assess the strength of the association between atypical hyperplasia and breast cancer. The rationale for developing a nonsurgical modality to document the presence of atypia is discussed.

RESULTS

Ductal lavage identifies atypical hyperplasia by retrieving epithelial cells shed into the ductal system with a specially designed catheter. Women with clinical evidence of increased breast cancer risk may consider ductal lavage as a means of determining whether abnormal proliferative activity is occurring in their breasts at a given point in time from ducts yielding fluid.

CONCLUSIONS

Ductal lavage is a minimally invasive procedure that facilitates the detection of atypia via retrieval of breast ductal fluid that can be evaluated cytologically. It can facilitate the selection of women who may benefit from breast cancer risk reduction intervention.

Chemoprevention of breast cancer: implications for postmenopausal women

Estrogen administration is associated with reduction in perimenopausal symptoms and the risk for several conditions affecting postmenopausal women. As estrogen administration also increases the risk for breast cancer, a common dilemma facing many women and their physicians is whether to use estrogen replacement therapy (ERT), a selective estrogen receptor modulator (SERM) that antagonises estrogenic effects in breast tissue but retains some estrogen agonist properties in other organs, or neither. For women with average to moderate risk of breast cancer and with perimenopausal symptoms, ERT may be the best short-term choice. For very high-risk women (>1% per year) with menopausal symptoms, alternatives to ERT might be offered and tried first. A diagnosis of ductal carcinoma in situ or invasive breast cancer within the last 2 to 5 years should be considered a relative contraindication for ERT unless the tumour was estrogen receptor negative. High-risk women without menopausal symptoms are the best candidates for the only currently approved drug for breast cancer risk reduction, tamoxifen. Although the drug is approved for women with a 5-year risk of breast cancer > or = 1.7% (0.34% per year), postmenopausal women most likely to experience a favourable benefit/risk ratio are those with a Gail estimated risk of >0.5% per year without a uterus or >1% per year if they retain their uterus. Tamoxifen should not be used in women with prior history of thromboembolic or precancerous uterine conditions. Tamoxifen is often used in Europe in conjunction with transdermal ERT in hysterectomised women without obvious loss of efficacy or increased risk of thromboembolism. Raloxifene is a second generation SERM with estrogen-like agonist effects on bone but with less uterine estrogen agonist activity than tamoxifen. Raloxifene may have less potent breast antiestrogenic effects than tamoxifen, particularly in a moderate- to high-estrogen environment. Raloxifene is approved for use in reducing risk of osteoporosis, but not breast cancer. Whether it is as effective as tamoxifen in reducing breast cancer risk in postmenopausal women is the subject of a current trial. All women regardless of breast cancer risk are advised to employ nonpharmacological risk reduction measures, including normalisation of bodyweight, exercise, adequate calcium and vitamin D intake, and avoidance of smoking and alcohol. The preventive options are best weighed during an individualised consultation where a woman's menopausal symptoms and risk for breast cancer and other diseases can be examined, and the options for improving postmenopausal health can be discussed.

Breast cancer risk assessment in patients seen in a gynecologic oncology clinic

The objective of this study was to determine if breast cancer risk assessment following the Gail model should be incorporated into a gynecologic oncology clinic. The Gail model was used to assess the risk of breast cancer in 329 patients with preinvasive lower genital tract disease (Pre, n = 86), invasive vulvar and cervical (Cx, n = 102), uterine (Ut, n = 87), and ovarian cancer (Ov, n = 54) seen in an inner city gynecologic oncology office. T-test, chi square test, and Pearson and Spearman correlation coefficients were used for statistical evaluation. A P-value of less than 0.05 was regarded significant. An estimated 5-year risk of breast cancer of 1.67 or more was noted in 9% of the Pre patients, 5% of Cx patients, 21% of the Ut patients, and 9% of the Ov patients. The difference between Cx and Ut patients was significant. The average 5-year risk was calculated at 0.77 for Pre patients, 0.77 for Cx patients, 1.18 for Ut patients, and 1.11 for Ov patients. These differences were significant, but mirror the age distribution. The average age was 43.6 for Pre patients, 52.2 years for Cx, 61.5 years for Ut, and 58.5 years for Ov patients; these differences were significant. When calculations were corrected for the mean age (53 years), there were no significant differences between groups regarding the average risk: Pre: 1.04, Cx: 0.81, Ut: 0.96, Ov: 0.97. Only eight patients (2.4%), six of them in the Pre and Cx group, would be expected to derive significant benefit from tamoxifen therapy. We conclude that elevated 5-year breast cancer risk to 1.67% or higher is noted in about 11% of patients seen in a gynecologic oncology office, mainly related to age and family history. Risk assessment and regular screening should be part of any follow-up exam.

Risk estimation for breast cancer development; a clinical perspective

Breast cancer is the commonest cancer among women and the second highest cause of cancer death. It remains a significant health problem and represents a significant worry for many women and their physician. During the last years, intensive research has been focused on accurate risk estimation for breast cancer development. The aim of these efforts is to identify the "high-risk" group of women for breast cancer development. Preventive strategies (including intensive surveillance, chemoprevention, or prophylactic mastectomy) may be applied for the women at high risk for breast cancer development. Given the many management options, it seems reasonable that management of the high-risk woman be tailored to the level of risk she is willing to accept. In estimating the risk for breast cancer development, several factors should be taken into account (including age, reproductive factors, such as age at menarche and age at menopause or pregnancy and age at first live birth, history of benign breast lesions or breast cancer in situ [LCIS/DCIS], prior history of breast cancer, history of familiar or hereditary breast cancer, and environmental and lifestyle factors). Recently, quantitative risk estimation is possible by combining multiple risk factors into a comprehensible risk expression; this is of significant clinical importance, since it will reduce the considerable variation in management among health care providers. The Gail and the Claus model are the most widely used models for quantitative risk estimation. However, the clinician should understand that all models have some limitations that should be recalled as they are applied. It should be emphasized that risk assessment is a serious undertaking and should only be performed by those who have in-depth knowledge about risk factors, family pedigree analysis, comparative statistics, genetics susceptibility testing and the science of probability.

Breast cancer risk in Ashkenazi BRCA1/2 mutation carriers: effects of reproductive history

BACKGROUND

Younger age at first birth and greater parity generally reduce the risk of developing breast cancer, but whether this reduced risk holds in women with a mutation in the BRCA1 or BRCA2 gene is unknown.

METHODS

In a Washington DC community-based study conducted in 1996, we tested 5318 Ashkenazi Jews for three BRCA1/2 founder mutations and identified 120 mutation carriers. Applying an extension of the "kin-cohort" analysis, we compared the effects of reproduction on breast cancer risk in carriers and noncarriers. We also used a case-case analysis among 288 participants who had been diagnosed with breast cancer.

RESULTS

In noncarriers, the estimated relative risk (RR) of breast cancer rose 5% with each 5-year increment in age at first birth (RR = 1.05; 95% confidence interval [CI] = 0.97-1.15). By contrast, the estimated risk in mutation carriers fell with each 5-year increment in age (RR = 0.65; 95% CI = 0.37-1.16). Among the 288 participants who were breast cancer survivors themselves, the comparison of carriers with noncarriers also showed no protection associated with early birth in the presence of a mutation in BRCA1 or BRCA2.

CONCLUSIONS

It is not yet clear whether the recognized breast cancer risk factors operate in the same way in women who carry a mutation in the BRCA1 or BRCA2 genes.

Who's liable for breast cancer prevention? Your patient can sue--and win--if preventive options aren't made clear

Strategies to reduce the likelihood of breast cancer in high-risk patients present complex medical-legal issues. An accurate and thorough medical history, objective calculation of risk, thorough discussion of preventive options and side effects, meticulous documentation of physician-patient interactions, and meticulous follow-up are essential. These elements form the foundation of a sound approach to breast cancer prevention in high-risk patients and should reduce physician liability if cancer occurs.

Chemoprevention for high-risk women: tamoxifen and beyond

The demonstration by the National Surgical Adjuvant Breast Project (NSABP) that 5 years of tamoxifen therapy is associated with an approximate 50% reduction in breast cancer incidence in high-risk women was a milestone in breast cancer prevention. Because tamoxifen is associated with increased risk of side-effects such as hot flashes, menstrual abnormalities, uterine cancer, and thromboembolic phenomena, its use will not be advisable or acceptable for all high-risk women. Women over 50 years of age appear to be at highest risk for serious adverse events, such as uterine cancer and thromboembolic phenomena. Individuals in whom tamoxifen-associated breast cancer risk reduction appears to outweigh risk of serious side-effects include women with prior in situ or estrogen receptor (ER)-positive invasive cancer, atypical hyperplasia, and/or women ages 35-49 with a calculated Gail 5-year risk of > or =1.7%, hysterectomized women aged 50 and older with a 5-year Gail risk of > or =2.5%, and nonhysterectomized women aged 50 and older with a 5-year Gail risk of >5.0%. It is not yet clear whether tamoxifen can reduce breast cancer incidence in women with BRCA1 and BRCA2 mutations, although preliminary evidence favors benefit for at least those with a BRCA2 mutation. Raloxifene is a selective ER modulator with less uterine estrogen agonist activity than tamoxifen, and it is hoped that it will result in fewer uterine cancers but will be equally efficacious in reducing the risk of breast cancer. The NSABP is currently conducting a randomized study of tamoxifen versus raloxifene in high-risk postmenopausal women. Approximately one third of invasive cancers are ER negative. Tamoxifen does not reduce the incidence of ER-negative cancers, nor does it appear to be effective in preventing the appearance of one third of ER-positive cancers. Priorities in prevention research are to develop (a) biomarkers to refine short-term risk assessments based on epidemiologic models, (b) biomarkers predictive of response to specific classes of preventive agents, (c) drugs with fewer side-effects and/or effective in ER-negative or ER-positive tamoxifen-resistant precancerous disease, and (d) efficient clinical trial models to assess new agent efficacy. Breast intraepithelial neoplasia (IEN) may be sampled by minimally invasive techniques and is an attractive short-term risk biomarker. Molecular abnormalities observed in IEN may be used to select potential agents for testing/therapy, and modulation of these abnormalities may be used in phase I trials to select appropriate doses and in phase II trials to assess response. Breast density volume and certain serum markers such as insulin-like growth factor-1 are also being studied as potential risk and response biomarkers. Reversal or prevention of advanced IEN as well as modulation of other risk biomarkers in randomized phase II and phase III trials is being evaluated as a means of more efficiently evaluating prevention drugs in the future. A number of agents are being developed that target molecular abnormalities in IEN, have fewer or different side effects than tamoxifen, and may be effective in ER-negative or tamoxifen-resistant disease.

Common hereditary cancers and implications for primary care

The identification of genes that place individuals at high risk of breast, ovarian, and colorectal cancer has greatly advanced our understanding of cancer predisposition over the past decade. This knowledge has received much attention from the media, and referrals to geneticists and surgeons, and requests for genetic testing, have risen. We review the published evidence for the management of people at increased risk of hereditary cancers, to draw attention to areas of uncertainty and to discuss implications for primary care. We focus on common inherited cancers, since they will have the greatest effect on clinical practice over the next decade. Cancer genetics offers a model of how information on the genetics of other common diseases could affect primary care in the future. Strategies to support the integration of genetic medicine in primary care are needed to enable primary-care practitioners to identify individuals at raised genetic risk and to reassure patients for whom genetic testing and increased surveillance offer little benefit.

Understanding mathematical models for breast cancer risk assessment and counseling

Chemoprevention and prophylactic surgery are effective interventions for lowering breast cancer incidence. However, these approaches are associated with risks of their own. Accurate individualized breast cancer risk assessment is an essential component of the risk/benefit analysis that must take place prior to implementing either of these strategies. Several mathematical models for estimating individual breast cancer risk have been proposed over the last decade. The Gail model is the most generally applicable model; however, it neglects family history information in second-degree relatives, treats pre- and postmenopausal breast cancer the same, and ignores personal histories of lobular neoplasia. The Claus model is a better family history model, but it does not assign any special relevance to histories of bilateral breast cancer or ovarian cancer, and neglects all of the nonfamily history information accounted for by the Gail model. BRCAPRO is a Bayesian family history model that calculates individual breast cancer probabilities based on the probability that a family carries a mutation in one of the BRCA genes. Though its treatment of family history information is more thorough than the other models, it neglects the nonfamily history risk factors accounted for by the Gail model and may not appreciate familial clustering unrelated to BRCA gene mutation. A thorough understanding of the principles of risk analysis and the available mathematical models is essential for anyone wishing to perform intervention counseling. This review describes the basic components of risk analysis, explains how the mathematical models work and compares the strengths and weaknesses of the various models. CancerGene is a software tool for running all of these models. It may be obtained without charge at http://www.swmed.edu/home_pages/cancergene.

Breast cancer risk assessment in indigent women at a public hospital

OBJECTIVES

The aims of this study were to estimate the 5-year breast cancer risk in indigent women presenting to the gynecology clinic at a public hospital and to determine whether routine use of the computerized Gail model for screening in this population identifies individuals at increased risk.

METHODS

A prospective study was performed over 1-year period (7/99-7/00) of women presenting to the gynecology and gynecologic oncology clinics at a public hospital. All women ages 35-60 years with no personal history of breast cancer were offered testing utilizing the computerized Gail model provided by the National Cancer Institute. Age, race, age at menarche, age at first live birth, number of first-degree relatives with breast cancer, number of breast biopsies, and number of breast biopsies diagnosed as atypical hyperplasia were documented. A calculated 5-year risk > or =1.67% was considered high-risk.

RESULTS

In all, 319 women enrolled, 121 (38%) with a history of gynecologic cancer and 198 (62%) without. The mean age was 46.9 years (range 35-60), and 28 (8.8%) patients had at least one first-degree relative with breast cancer. Ethnicity included 206 (65%) African American, 52 (16%) Caucasian, 45 (14%) Hispanic, and 16 (5%) oriental. Eight (2.5%) women had a 5-year risk > or =1.67%. The mean 5-year risk for all patients was 0.68% (0.55% for African American versus 0.90% for Caucasian/other, P < 0.001).

CONCLUSION

Estimating 5-year breast cancer risk using the Gail model in indigent women may identify individuals at increased risk. Compared to other patients, African American women appeared to have a lower estimated 5-year risk according to the currently available model. The routine utilization of the Gail model deserves further investigation in the indigent minority population.

Validation of the Gail et al. model of breast cancer risk prediction and implications for chemoprevention

BACKGROUND

Women and their clinicians are increasingly encouraged to use risk estimates derived from statistical models, primarily that of Gail et al., to aid decision making regarding potential prevention options for breast cancer, including chemoprevention with tamoxifen.

METHODS

We evaluated both the goodness of fit of the Gail et al. model 2 that predicts the risk of developing invasive breast cancer specifically and its discriminatory accuracy at the individual level in the Nurses' Health Study. We began with a cohort of 82 109 white women aged 45-71 years in 1992 and applied the model of Gail et al. to these women over a 5-year follow-up period to estimate a 5-year risk of invasive breast cancer. All statistical tests were two-sided.

RESULTS

The model fit well in the total sample (ratio of expected [E] to observed [O] numbers of cases = 0.94; 95% confidence interval [CI] = 0.89 to 0.99). Underprediction was slightly greater for younger women (<60 years), but in most age and risk factor strata, E/O ratios were close to 1.0. The model fit equally well (E/O ratio = 0.93; 95% CI = 0.87 to 0.99) in a subset of women reporting recent screening (i.e., within 1 year before the baseline); among women with an estimated 5-year risk of developing invasive breast cancer of 1.67% or greater, the E/O ratio was 1.04 (95% CI = 0.96 to 1.12). The concordance statistic, which indicates discriminatory accuracy, for the Gail et al. model 2 when used to estimate 5-year risk was 0.58 (95% CI = 0.56 to 0.60). Only 3.3% of the 1354 cases of breast cancer observed in the cohort arose among women who fell into age-risk strata expected to have statistically significant net health benefits from prophylactic tamoxifen use.

CONCLUSIONS

The Gail et al. model 2 fit well in this sample in terms of predicting numbers of breast cancer cases in specific risk factor strata but had modest discriminatory accuracy at the individual level. This finding has implications for use of the model in clinical counseling of individual women.

Results of a community pharmacy-based breast cancer risk-assessment and education program

We tested the hypothesis that an education program addressing breast cancer screening schedules and modalities coupled with a breast cancer risk assessment provided by community pharmacists can increase women's confidence in performing screening practices endorsed by the American Cancer Society (ACS). This randomized, paired, pre-post study was conducted in six community pharmacies and two health-screening fairs; subjects were 140 women over 18 years of age. The pharmacist-administered program used the Breast Cancer Risk-Assessment Tool (Gail model) software provided by the National Cancer Institute of the National Institutes of Health. In addition, pharmacists provided education and training on breast self-examination (BSE), clinical breast examination (CBE), and mammography. Adherence to ACS guidelines for monthly BSE increased from 31% to 56% (p<0.001) for all women 6 months after the program. Performance of monthly BSE by women considered at high risk for developing breast cancer increased from 20% to 60% (p<0.005). The mean number of BSEs performed over 6 months increased from 2.69 to 4.09 (p<0.001). Women's confidence performing correct BSE improved from 6.41 to 7.04 (p<0.001) on a scale of 0-10. Adherence to ACS guidelines for CBE and mammography did not reveal statistically significant improvements except for better adherence to CBE in women aged 40-49 years (81% to 97%, p<0.025). The strength of the pharmacists' intervention may not appear as manipulation of high-risk patients' behavior but as improvement of self-directed behaviors, such as BSE, across all age groups.

Risk models in genetic epidemiology

Advances in the identification and treatment of genetically transmitted diseases have lead to an increased need for reliable estimates of genetic susceptibility risk. These estimates are used in clinic settings to identify individuals at increased risk of being a carrier of a disease susceptibility allele as well as to define the probability of developing a particular disease given one is a carrier. Accurate assessment of these probabilities is extremely important given the implications for medical decision making including the identification of patients who might benefit from genetic counselling or from entry into clinical trials. A wide range of risk models has been proposed including those that utilize logistic regression, Cox proportional hazards regression, log-incidence models, and Bayesian modelling. The specific data used to create the various risk models varies by disease and may include molecular, epidemiologic, and clinical information although, in general, family history remains the primary variable of interest, particularly for those diseases for which a susceptibility allele(s) has yet to be identified. When permitted by sample size, researchers also attempt to measure the effect of any gene-environment interaction. In this paper we give an overview of the various definitions of risk as well as several of the more frequently used methods of risk estimation in genetic epidemiology at present. In addition, the means by which different methods are able to provide a measure of error or uncertainty associated with a given risk estimate will be discussed. Applications to risk modelling for breast cancer are given the disease for which risk assessment has probably been most extensively defined.

Short-term breast cancer prediction by random periareolar fine-needle aspiration cytology and the Gail risk model

BACKGROUND

: Biomarkers are needed to refine short-term breast cancer risk estimates from epidemiologic models and to measure response to prevention interventions. The purpose of our study was to determine whether the cytologic appearance of epithelial cells obtained from breast random periareolar fine-needle aspirates or molecular marker expression in these cells was associated with later breast cancer development.

METHODS

: Four hundred eighty women who were eligible on the basis of a family history of breast cancer, prior precancerous biopsy, and/or prior invasive cancer were enrolled in a single-institution, prospective trial. Their risk of breast cancer according to the Gail model was calculated, and random periareolar fine-needle aspiration was performed at study entry. Cells were characterized morphologically and analyzed for DNA aneuploidy by image analysis and for the expression of epidermal growth factor receptor, estrogen receptor, p53 protein, and HER2/NEU protein by immunocytochemistry. All statistical tests are two-sided.

RESULTS

: At a median follow-up time of 45 months after initial aspiration, 20 women have developed breast cancer (invasive disease in 13 and ductal carcinoma in situ in seven). With the use of multiple logistic regression and Cox proportional hazards analysis, subsequent cancer was predicted by evidence of hyperplasia with atypia in the initial fine-needle aspirate and a 10-year Gail projected probability of developing breast cancer. Although expression of epidermal growth factor receptor, estrogen receptor, p53, and HER2/NEU was statistically significantly associated with hyperplasia with atypia, it did not predict the development of breast cancer in multivariable analysis.

CONCLUSION

: Cytomorphology from breast random periareolar fine-needle aspirates can be used with the Gail risk model to identify a cohort of women at very high short-term risk for developing breast cancer. We recommend that cytomorphology be studied for use as a potential surrogate end point in prevention trials.

Prevention of breast cancer

With the advent of screening and the increased incidence of breast cancer, concern for the prevention of breast cancer has become forefront in today's society. Determining individual risk is the key to prescribing prevention. Prevention of breast cancer is still under clinical investigation with only one drug, tamoxifen, showing benefit in high risk patients. This paper reviews the possible sites for prevention of neoplastic transformation via biomarkers in a breast cell as well as the investigational drugs and their potential use in the chemoprevention of breast cancer.

Chemoprevention of breast cancer in the older patient

Age is the most important risk factor for the development of breast cancer. The risk of breast cancer continues to increase in American women until the age of 80 years. A family history of breast cancer helps identify those who possibly have the highest risk of developing breast cancer; however, most women who develop breast cancer do not have a first-degree relative with a history of breast cancer. Currently, the Gail model is a commonly used model to identify risk, and this model has now been validated in several populations of women undergoing screening for breast cancer. The first large-scale breast cancer prevention trial investigating the preventive effects of tamoxifen has demonstrated a decrease in the development of breast cancer by almost 50% in the women in the tamoxifen treatment arm as compared with those receiving placebo. The NSABP P-1 trial was the largest of the three tamoxifen breast cancer prevention trials and had the greatest power to detect a difference between the two treatment groups in breast cancer events. This trial also included the largest percentage of postmenopausal women. It is unclear why the Italian and Royal Marsden Hospital trials had negative results regarding the preventive effects of tamoxifen. These two trials were strikingly different from the NSABP P-1 trial, however, and they included a different population of women. The issues surrounding the use of HRT for treatment of hot flashes in the Italian and Royal Marsden Hospital trials adds to the controversy concerning the negative results of these trials. The new SERM, raloxifene, has shown promise in preliminary studies as a preventive agent for breast cancer. The STAR trial will open soon and will evaluate the efficacy of raloxifene in preventing breast cancer in a prospective fashion, comparing its efficacy with tamoxifen treatment. Other endpoints will evaluate side effects such as menopausal symptoms, endometrial cancer, thromboembolic events, and benefits regarding serum lipids and incidence of osteoporotic bone fractures. The development of SERMs results from an understanding of novel mechanisms of ER modulation and allows targeting for favorable effects in specific tissues. The challenge is to develop an ideal SERM that is effective in preventing breast cancer and does not increase the risk of endometrial cancer, while providing beneficial estrogenic effects on serum lipids and bone mineral density changes. Estrogen receptor-mediated intracellular processes are complex. There are at least two different types of estrogen receptors. The alpha receptors predominate in the breast and uterus, and the beta receptors predominate in the bone and blood vessels. Many proteins also interact with these receptors as co-activators or co-repressors. Transcription-activating factors modulate the effects of estrogen on its target genes. Future prevention strategies may use a combined targeted approach to inhibit ER-mediated cancer progression pathways. The retinoids are under investigation in prevention studies for a multitude of cancers, because they have been shown to inhibit cellular proliferation and to induce cellular differentiation. The retinoid 4HPR was selected for use in breast cancer prevention studies because of its low toxicity profile and prevention efficacy in preclinical studies. It is now being used in combination with tamoxifin in a phase II breast cancer prevention trial. Multiple surrogate endpoint biomarkers are being measured before and after treatment, including measurement of serum IGF-I levels. Future directions in breast cancer prevention include the development of more potent hormonal therapies that completely inhibit ER-mediated cancer progression and, ultimately, multitargeted therapies involving agents that work synergistically.

Weighing the risks and benefits of tamoxifen treatment for preventing breast cancer

BACKGROUND

In response to findings from the Breast Cancer Prevention Trial that tamoxifen treatment produced a 49% reduction in the risk of invasive breast cancer in a population of women at elevated risk, the National Cancer Institute sponsored a workshop on July 7 and 8, 1998, to develop information to assist in counseling and in weighing the risks and benefits of tamoxifen. Our study was undertaken to develop tools to identify women for whom the benefits outweigh the risks.

METHODS

Information was reviewed on the incidence of invasive breast cancer and of in situ lesions, as well as on several other health outcomes, in the absence of tamoxifen treatment. Data on the effects of tamoxifen on these outcomes were also reviewed, and methods were developed to compare the risks and benefits of tamoxifen.

RESULTS

The risks and benefits of tamoxifen depend on age and race, as well as on a woman's specific risk factors for breast cancer. In particular, the absolute risks from tamoxifen of endometrial cancer, stroke, pulmonary embolism, and deep vein thrombosis increase with age, and these absolute risks differ between white and black women, as does the protective effect of tamoxifen on fractures. Tables and aids are developed to describe the risks and benefits of tamoxifen and to identify classes of women for whom the benefits outweigh the risks.

CONCLUSIONS

Tamoxifen is most beneficial for younger women with an elevated risk of breast cancer. The quantitative analyses presented can assist health care providers and women in weighing the risks and benefits of tamoxifen for reducing breast cancer risk.

Validation studies for models projecting the risk of invasive and total breast cancer incidence

BACKGROUND

In 1989, Gail and colleagues developed a model for estimating the risk of breast cancer in women participating in a program of annual mammographic screening (designated herein as model 1). A modification of this model to project the absolute risk of developing only invasive breast cancer is referred to herein as model 2. We assessed the validity of both models by employing data from women enrolled in the Breast Cancer Prevention Trial.

METHODS

We used data from 5969 white women who were at least 35 years of age and without a history of breast cancer. These women were in the placebo arm of the trial and were screened annually. The average follow-up period was 48.4 months. We compared the observed number of breast cancers with the predicted numbers from the models.

RESULTS

In terms of absolute risk, the ratios of total expected to observed numbers of cancers (95% confidence intervals [CIs]) were 0.84 (0. 73-0.97) for model 1 and 1.03 (0.88-1.21) for model 2, respectively. Within the age groups of 49 years or less, 50-59 years, and 60 years or more, the ratios of expected to observed numbers of breast cancers (95% CIs) for model 1 were 0.91 (0.73-1.14), 0.96 (0.73-1. 28), and 0.66 (0.52-0.86), respectively. Thus, model 1 underestimated breast cancer risk in women more than 59 years of age. For model 2, the risk ratios (95% CIs) were 0.93 (0.72-1.22), 1.13 (0.83-1.55), and 1.05 (0.80-1.41), respectively. Both models exhibited a tendency to overestimate risk for women classified in the higher quintiles of predicted 5-year risk and to underestimate risk for those in the lower quintiles of the same.

CONCLUSION

Despite some limitations, these methods provide useful information on breast cancer risk for women who plan to participate in an annual mammographic screening program.

American Society of Clinical Oncology technology assessment on breast cancer risk reduction strategies: tamoxifen and raloxifene

OBJECTIVE

To conduct an evidence-based technology assessment to determine whether tamoxifen and raloxifene as breast cancer risk-reduction strategies are appropriate for broad-based conventional use in clinical practice.

POTENTIAL INTERVENTION

Tamoxifen and raloxifene.

OUTCOME

Outcomes of interest include breast cancer incidence, breast cancer-specific survival, overall survival, and net health benefits.

EVIDENCE

A comprehensive, formal literature review was conducted for tamoxifen and raloxifene on the following topics: breast cancer risk reduction; tamoxifen side effects and toxicity, including endometrial cancer risk; tamoxifen influences on nonmalignant diseases, including coronary heart disease and osteoporosis; and decision making by women at risk for breast cancer. Testimony was collected from invited experts and interested parties.

VALUES

More weight was given to publications that described randomized trials. BENEFITS/HARMS/COSTS: The American Society of Clinical Oncology (ASCO) Working Group acknowledges that a woman's decision regarding breast cancer risk-reduction strategies will depend on the importance and weight attributed to the information provided regarding both cancer and non-cancer-related risks.

CONCLUSIONS

For women with a defined 5-year projected risk of breast cancer of >/= 1.66%, tamoxifen (at 20 mg/d for up to 5 years) may be offered to reduce their risk. It is premature to recommend raloxifene use to lower the risk of developing breast cancer outside of a clinical trial setting. On the basis of available information, use of raloxifene should currently be reserved for its approved indication to prevent bone loss in postmenopausal women. Conclusions are based on single-agent use of the drugs. At the present time, the effect of using tamoxifen or raloxifene with other medications (such as hormone replacement therapy), or using tamoxifen and raloxifene in combination or sequentially, has not been studied adequately. The continuing use of placebo-controlled trials in other risk-reduction trials highlights the current unanswered issues concerning the use of such interventions, especially when the influence on net health benefit remains to be determined. Breast cancer risk reduction is a rapidly evolving area. This technology assessment represents an ongoing process with existing plans to monitor and review data and to update recommendations in a timely matter. (See

VALIDATION

The conclusions of the Working Group were evaluated by the ASCO Health Services Research Committee and by the ASCO Board of Directors.

SPONSOR

American Society of Clinical Oncology.

Identification of the woman at risk for breast cancer: problem solved?

The clinical availability of antiestrogens to reduce breast cancer incidence has focused increased attention on the ability to identify women at increased risk for breast cancer development. Multiple risk factors, which can be grouped under the headings of genetic and familial factors, hormonal factors, benign breast disease, and environmental factors have been described. However, of these risk factors, only genetic mutations and atypical hyperplasia, lobular carcinoma in situ, and ductal carcinoma in situ have a relative risk of four or more. Many of the other risk factors, although associated with statistically significant increases in risk in large populations, are of little practical significance for the individual woman. Lack of knowledge of the interactions among various positive and negative risk factors also complicates the evaluation of risk. In addition, the impact of some risk factors may not be constant over time, and the majority of data on risk come from studies of white women, and little is known about the impact of ethnic diversity on these factors. Finally, there is no consensus about what level of increase in risk is necessary for a women to be labeled "high risk." It is important to recognize that only 50% of breast cancers occur in women with identifiable risk factors other than age. Thus, an improved ability to define risk status is needed if prevention studies directed at high-risk women are to have a major impact on breast cancer incidence and mortality.

Efficacy of bilateral prophylactic mastectomy in women with a family history of breast cancer

BACKGROUND

Options for women at high risk for breast cancer include surveillance, chemoprevention, and prophylactic mastectomy. The data on the outcomes for surveillance and prophylactic mastectomy are incomplete.

METHODS

We conducted a retrospective study of all women with a family history of breast cancer who underwent bilateral prophylactic mastectomy at the Mayo Clinic between 1960 and 1993. The women were divided into two groups - high risk and moderate risk - on the basis of family history. A control study of the sisters of the high-risk probands and the Gail model were used to predict the number of breast cancers expected in these two groups in the absence of prophylactic mastectomy.

RESULTS

We identified 639 women with a family history of breast cancer who had undergone bilateral prophylactic mastectomy: 214 at high risk and 425 at moderate risk. The median length of follow-up was 14 years. The median age at prophylactic mastectomy was 42 years. According to the Gall model, 37.4 breast cancers were expected in the moderate-risk group; 4 breast cancers occurred (reduction in risk, 89.5 percent; P<0.001). We compared the numbers of breast cancers among the 214 high-risk probands with the numbers among their 403 sisters who had not undergone prophylactic mastectomy. Of these sisters, 38.7 percent (156) had been given a diagnosis of breast cancer (115 cases were diagnosed before the respective proband's prophylactic mastectomy, 38 were diagnosed afterward, and the time of the diagnosis was unknown in 3 cases). By contrast, breast cancer was diagnosed in 1.4 percent (3 of 214) of the probands. Thus, prophylactic mastectomy was associated with a reduction in the incidence of breast cancer of at least 90 percent.

CONCLUSIONS

In women with a high risk of breast cancer on the basis of family history, prophylactic mastectomy can significantly reduce the incidence of breast cancer.