Cancer risks among BRCA1 and BRCA2 mutation carriers

BRCA1 and BRCA2 mutations increase breast and ovarian cancer risks substantially enough to warrant risk reduction surgery, despite variable risk estimates. Underlying this variability are methodological issues, and also complex genetic and nongenetic effects. Although many modifying factors are unidentified, known factors can already be incorporated in individualised risk prediction.     

Outcome of preventive surgery and screening for breast and ovarian cancer in BRCA mutation carriers.

PURPOSE: To prospectively determine the impact of genetic counseling and testing on risk-reduction strategies and cancer incidence in a cohort of individuals at hereditary risk for breast and ovarian cancer. PATIENTS AND METHODS: Two hundred fifty-one individuals with BRCA mutations were identified at a single comprehensive cancer center from May 1, 1995, through October 31, 2000. Uniform recommendations regarding screening and preventive surgery were provided in the context of genetic counseling. Patients were followed for a mean of 24.8 months (range, 1.6 to 66.0 months) using standardized questionnaires, chart reviews, and contact with primary physicians. RESULTS: Frequency of cancer surveillance by physical examinations and imaging studies increased after genetic counseling and testing. Twenty-one breast, ovarian, primary peritoneal, or fallopian tube cancers were detected after receipt of genetic test results. Among 29 individuals choosing risk-reducing mastectomy after testing, two were found to have occult intraductal breast cancers. Among 90 individuals who underwent risk-reducing salpingo-oophorectomy, one early-stage ovarian neoplasm and one early-stage fallopian tube neoplasm were found. Radiographic or tumor marker-based screening detected six breast cancers, five of which were stage 0/I, one early-stage primary peritoneal cancer, and three stage I or II ovarian cancers. Six additional breast cancers were detected by physical examination between radiographic screening intervals; four of these six tumors were stage I. No stage III or stage IV malignancies were detected after genetic testing. CONCLUSION: This study provides prospective evidence that genetic counseling and testing increased surveillance and led to risk-reducing operations, which resulted in diagnosis of early-stage tumors in patients with BRCA1 and BRCA2 mutations.     

Annual screening strategies in BRCA1 and BRCA2 gene mutation carriers: a comparative effectiveness analysis

BACKGROUND:

Although breast cancer screening with mammography and magnetic resonance imaging (MRI) is recommended for breast cancer‐susceptibility gene (BRCA) mutation carriers, there is no current consensus on the optimal screening regimen.

METHODS:

The authors used a computer simulation model to compare 6 annual screening strategies (film mammography [FM], digital mammography [DM], FM and magnetic resonance imaging [MRI] or DM and MRI contemporaneously, and alternating FM/MRI or DM/MRI at 6‐month intervals) beginning at ages 25 years, 30 years, 35 years, and 40 years, and 2 strategies of annual MRI with delayed alternating DM/FM versus clinical surveillance alone. Strategies were evaluated without and with mammography‐induced breast cancer risk using 2 models of excess relative risk. Input parameters were obtained from the medical literature, publicly available databases, and calibration.

RESULTS:

Without radiation risk effects, alternating DM/MRI starting at age 25 years provided the highest life expectancy (BRCA1, 72.52 years, BRCA2, 77.63 years). When radiation risk was included, a small proportion of diagnosed cancers was attributable to radiation exposure (BRCA1, <2%; BRCA2, <4%). With radiation risk, alternating DM/MRI at age 25 years or annual MRI at age 25 years/delayed alternating DM at age 30 years was the most effective, depending on the radiation risk model used. Alternating DM/MRI starting at age 25 years also produced the highest number of false‐positive screens per woman (BRCA1, 4.5 BRCA2, 8.1).

CONCLUSIONS:

Annual MRI at age 25 years/delayed alternating DM at age 30 years is probably the most effective screening strategy in BRCA mutation carriers. Screening benefits, associated risks, and personal acceptance of false‐positive results should be considered in choosing the optimal screening strategy for individual women. Cancer 2012. © 2011 American Cancer Society.     

Effectiveness of preventive interventions in BRCA1/2 gene mutation carriers: a systematic review

A systematic review of the literature was conducted to assess the outcomes of preventive interventions (prophylactic surgery, intensive cancer screening, and chemoprevention) in women who carry mutations in BRCA1/2 genes, in terms of reducing breast and gynaecological cancer incidence and/or mortality. A search for relevant articles published between 1996 and 2005 (inclusive) was run on Medline, Embase and other databases. From the 749 journal articles retrieved from this search strategy, 18 studies were eligible for this review (2 systematic reviews, 10 cohort studies and 6 case-control studies). The critical appraisal of the studies was performed by two independent reviewers with a list of ad hoc selected criteria. The synthesis of results was qualitative. Mastectomy and prophylactic gynaecological surgery (oophorectomy or salpingo-oophorectomy) reduced breast and gynaecological cancer incidence in carriers of BRCA mutations, by comparison to surveillance. However, all the studies presented flaws in internal and external validity, none of these preventive interventions is risk-free, and protection against breast and gynaecological cancer, as well as other cancers linked to BRCA mutations, is incomplete. No studies comparing surveillance programmes of varying intensity were found. Exposure to drugs (tamoxifen, and oral contraceptives) in women carrying BRCA mutations was assessed through a limited number of papers. All of these were case-control studies with prevalent cases and presented major methodological flaws.     

Risk-reducing surgery increases survival in BRCA1/2 mutation carriers unaffected at time of family referral

The aim of this study was to establish if risk-reducing surgery (RRS) increases survival among BRCA1/2 carriers without breast/ovarian cancer at the time of family referral. Female BRCA1/2 carriers were identified from the Manchester Genetic Medicine Database. Those patients alive and unaffected at the date of first family ascertainment were included in this study. Female first-degree relatives (FDRs) without predictive genetic testing who otherwise met eligibility criteria were also included. The effect of breast and ovarian RRS on survival was analysed. The survival experiences of RRS and non-RRS patients, stratified by BRCA status, were examined with Kaplan–Meier curves and contrasted using log-rank tests and Cox models. 691 female BRCA1/2 mutation carriers without breast or ovarian cancer at time of family ascertainment were identified; 346 BRCA1 and 345 BRCA2. 105 BRCA1 carriers and 122 BRCA2 carriers developed breast cancer during follow-up. The hazard of death was statistically significantly lower (P < 0.001) following RRS versus no RRS. 10-year survival for women having RRS was 98.9 % (92.4–99.8 %) among BRCA1 and 98.0 % (92.2–99.5 %) among BRCA2 carriers. This survival benefit with RRS remained significant after FDRs were added. Women who had any form of RRS had increased survival compared to those who did not have RRS; a further increase in survival was seen among women who had both types of surgery. However, formal evidence for a survival advantage from bilateral mastectomy alone requires further research.     

Breast cancer risk among male BRCA1 and BRCA2 mutation carriers

Men who carry germline mutations in the BRCA2 gene have a higher risk of developing breast carcinoma than men in the general population. Men who carry germline mutations in the BRCA1 gene may also be at a higher risk for breast carcinoma, but this association is not as well established. We evaluated the risks of developing breast carcinoma for male BRCA1 and BRCA2 mutation carriers in the US population based on data from 1939 families with 97 male subjects with breast carcinoma that were collected from eight centers across the National Cancer Institute's Cancer Genetics Network. At all ages, the cumulative risks of male breast cancer were higher in both BRCA1 and BRCA2 mutation carriers than in noncarriers. The relative risks of developing breast cancer were highest for men in their 30s and 40s and decreased with increasing age. Both the relative and cumulative risks were higher for BRCA2 mutation carriers than for BRCA1 mutation carriers. The estimated cumulative risk of breast carcinoma for male BRCA1 mutation carriers at age 70 years was 1.2% (95% confidence interval [CI] = 0.22% to 2.8%) and for BRCA2 mutation carriers, 6.8% (95% CI = 3.2% to 12%).     

Efficacy of bilateral prophylactic mastectomy in BRCA1 and BRCA2 gene mutation carriers.

BACKGROUND: In women with a family history of breast cancer, bilateral prophylactic mastectomy is associated with a decreased risk of subsequent breast cancer of approximately 90%. We examined the association between bilateral prophylactic mastectomy and breast cancer risk in women at high risk for breast cancer who also had mutations in BRCA1 and BRCA2 genes. METHODS: We obtained blood samples from 176 of the 214 high-risk women who participated in our previous retrospective cohort study of bilateral prophylactic mastectomy. We used conformation-sensitive gel electrophoresis and direct sequence analysis of the blood specimens to identify women with mutations in BRCA1 and BRCA2. The carriers' probabilities of developing breast cancer were estimated from two different penetrance models. RESULTS: We identified 26 women with an alteration in BRCA1 or BRCA2. Eighteen of the mutations were considered to be deleterious and eight to be of uncertain clinical significance. None of the 26 women has developed breast cancer after a median of 13.4 years of follow-up (range, 5.8-28.5 years). Three of the 214 women are known to have developed a breast cancer after prophylactic mastectomy. For two of these women, BRCA1 and BRCA2 screening was negative, and no blood specimen was available for the third. Estimations of the effectiveness of prophylactic mastectomy were performed, considering this woman as both a mutation carrier and a noncarrier. These calculations predicted that six to nine breast cancers should have developed among the mutation carriers, which translates into a risk reduction, after bilateral prophylactic mastectomy, of 89.5%-100% (95% confidence interval = 41.4% to 100%). CONCLUSIONS: Prophylactic mastectomy is associated with a substantial reduction in the incidence of subsequent breast cancer not only in women identified as being at high risk on the basis of a family history of breast cancer but also in known BRCA1 or BRCA2 mutation carriers.     

Parity and breast cancer risk among BRCA1 and BRCA2 mutation carriers

Introduction

Increasing parity and age at first full-term pregnancy are established risk factors for breast cancer in the general population. However, their effects among BRCA1 and BRCA2 mutation carriers is still under debate. We used retrospective data on BRCA1 and BRCA2 mutation carriers from the UK to assess the effects of parity-related variables on breast cancer risk.

Methods

The data set included 457 mutation carriers who developed breast cancer (cases) and 332 healthy mutation carriers (controls), ascertained through families seen in genetic clinics. Hazard ratios were estimated by using a weighted cohort approach.

Results

Parous BRCA1 and BRCA2 mutation carriers were at a significantly lower risk of developing breast cancer (hazard ratio 0.54, 95% confidence interval 0.37 to 0.81; p = 0.002). The protective effect was observed only among carriers who were older than 40 years. Increasing age at first live birth was associated with an increased breast cancer risk among BRCA2 mutation carriers (p trend = 0.002) but not BRCA1 carriers. However, the analysis by age at first live birth was based on small numbers.

Conclusion

The results suggest that the relative risks of breast cancer associated with parity among BRCA1 and BRCA2 mutation carriers may be similar to those in the general population and that reproductive history may be used to improve risk prediction in carriers.     

Decision analysis of prophylactic surgery or screening for BRCA1 mutation carriers: a more prominent role for oophorectomy.

PURPOSE: BRCA1 mutation carriers have a high risk of developing breast and ovarian cancer. Carriers may opt for prophylactic surgery and screening. Recent data suggesting that prophylactic oophorectomy reduces breast cancer risk have been incorporated in a decision analysis. METHODS: A Markov model was developed to compare LE and QALE following four strategies: (1) prophylactic mastectomy and prophylactic oophorectomy (PMPO), (2) screening for breast cancer and prophylactic oophorectomy (BSPO), (3) prophylactic mastectomy and screening for ovarian cancer (PMOS), and (4) screening for breast and ovarian cancer (BSOS). The analysis was performed for a high (85% breast cancer, 63% ovarian cancer) and medium (56% breast cancer, 16% ovarian cancer) risk level. Utilities for the health states after prophylactic surgery were obtained from mutation carriers. Other model parameter values were obtained from the literature. Sensitivity analyses were performed. RESULTS: When compared with BSOS, the average gain in LE for 30-year-old carriers in the high (medium) risk group was 11.7 (6.6) years for PMPO, 9.5 (5.3) years for BSPO, and 4.9 (4.4) years for PMOS. For 30-year-old carriers, BSPO had a QALE advantage when PO was performed before age 40. In the medium-risk group, there was a stronger advantage for BSPO when QALE was considered. CONCLUSION: PMPO is the most effective strategy to prolong life. However, if patient preferences were taken into account, BSPO tends to be a better strategy in most women at medium risk or in young women at high risk when PO was performed before age 40.     

Bilateral prophylactic oophorectomy and bilateral prophylactic mastectomy in a prospective cohort of unaffected BRCA1 and BRCA2 mutation carriers

BACKGROUND: Women with BRCA1 or BRCA2 (BRCA1/2) mutations can reduce cancer incidence and mortality by using bilateral prophylactic oophorectomy (BPO) or bilateral prophylactic mastectomy (BPM). The availability of these risk-reduction strategies is an important consideration in the decision to undergo genetic testing. PATIENTS AND METHODS: We evaluated the use of BPO and BPM in a prospective sample of 537 female BRCA1/2 mutation carriers from 17 centers in North America and Europe. These women were aged > 30 years, had no BPM, BPO, breast cancer, or ovarian cancer before the disclosure of their genetic test results and were followed for > or = 6 months. RESULTS: Bilateral prophylactic oophorectomy is used significantly more frequently than BPM (55% vs. 21%; P < .001). Bilateral prophylactic oophorectomy was more common among women age > or = 40 years compared with women aged < 40 years (68% vs. 43%; P < .001) and among parous women compared with nulliparous women (60% vs. 39%; P < .001). There was no difference in BPM (P = .83) or BPO (P = .09) in BRCA1 versus BRCA2 carriers. Multivariate models identified age and parity as a predictor of BPO in BRCA1 carriers; age and ovarian cancer family history in BRCA2 carriers; parity and ovarian cancer family history as a predictor of BPM in BRCA1 carriers; and smoking and ovarian cancer family history in BRCA2 carriers. CONCLUSION: Bilateral prophylactic oophorectomy is more commonly used than BPM in unaffected BRCA1/2 mutation carriers. Parity, age, and family history can also influence BPO and BPM uptake. Consistent with current recommendations, BPO is used by the majority of parous women aged > 40 years.     

Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers

Although there are several plausible biologic mechanisms whereby coffee consumption might influence the risk of breast cancer, epidemiologic evidence is limited. We assessed the association between coffee consumption and breast cancer risk among high-risk women who carry BRCA mutations. We performed a matched case-control analysis on 1,690 women with a BRCA1 or BRCA2 mutation from 40 centers in 4 countries. Average lifetime coffee consumption was estimated via a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for potential confounders, the ORs for breast cancer in BRCA carriers who habitually drank 0, 1-3, 4-5 and 6 or more cups of coffee were 1.00, 0.90 (95% CI 0.72-1.12), 0.75 (95% CI 0.47-1.19) and 0.31 (95% CI 0.13-0.71; p-trend = 0.02). The effect was limited to the consumption of caffeinated coffee. These results suggest that among women with BRCA gene mutation, coffee consumption is unlikely to be harmful and that high levels of consumption may in fact be related to reduced breast cancer risk.     

International variation in rates of uptake of preventive options in BRCA1 and BRCA2 mutation carriers

Several options for cancer prevention are available for women with a BRCA1 or BRCA2 mutation, including prophylactic surgery, chemoprevention and screening. The authors report on preventive practices in women with mutations from 9 countries and examine differences in uptake according to country. Women with a BRCA1 or BRCA2 mutation were contacted after receiving their genetic test result and were questioned regarding their preventive practices. Information was recorded on prophylactic mastectomy, prophylactic oophorectomy, use of tamoxifen and screening (MRI and mammography). Two thousand six hundred seventy-seven women with a BRCA1 or BRCA2 mutation from 9 countries were included. The follow-up questionnaire was completed a mean of 3.9 years (range 1.5-10.3 years) after genetic testing. One thousand five hundred thirty-one women (57.2%) had a bilateral prophylactic oophorectomy. Of the 1,383 women without breast cancer, 248 (18.0%) had had a prophylactic bilateral mastectomy. Among those who did not have a prophylactic mastectomy, only 76 women (5.5%) took tamoxifen and 40 women (2.9%) took raloxifene for breast cancer prevention. Approximately one-half of the women at risk for breast cancer had taken no preventive option, relying solely on screening. There were large differences in the uptake of the different preventive options by country of residence. Prophylactic oophorectomy is now generally accepted by women and their physicians as a cancer preventive measure. However, only the minority of women with a BRCA1 or BRCA2 mutation opt for prophylactic mastectomy or take tamoxifen for the prevention of hereditary breast cancer. Approximately one-half of women at risk for breast cancer rely on screening alone.     

Clinical management of BRCA1 and BRCA2 mutation carriers

The cancer susceptibility genes BRCA1 and BRCA2 appear to be responsible for virtually all hereditary breast ovarian families, and a smaller subset of hereditary site-specific breast cancer families. Fortunately, effective strategies have been developed to reduce the risk for the development of breast and ovarian cancer in women with BRCA1/2 mutations, making genetic testing for these mutations an important part of the management at women with a strong family history of these diseases. Here, we review the current evidence for risk reduction strategies and outline future research directions.     

Contralateral breast cancer in BRCA1 and BRCA2 mutation carriers.

PURPOSE: To estimate the risk of contralateral breast cancer in BRCA1 and BRCA2 carriers after diagnosis and to determine which factors are predictive of the risk of a second primary breast cancer. PATIENTS AND METHODS: Patients included 491 women with stage I or stage II breast cancer, for whom a BRCA1 or BRCA2 mutation had been identified in the family. Patients were followed from the initial diagnosis of cancer until contralateral mastectomy, contralateral breast cancer, death, or last follow-up. RESULTS: The actuarial risk of contralateral breast cancer was 29.5% at 10 years. Factors that were predictive of a reduced risk were the presence of a BRCA2 mutation (v BRCA1 mutation; hazard ratio [HR], 0.73; 95% CI, 0.47 to 1.15); age 50 years or older at first diagnosis (v 相似文献   

The penetrance of ductal carcinoma in situ among BRCA1 and BRCA2 mutation carriers

Ductal carcinoma in situ (DCIS) is a precancerous lesion of the female breast and is strongly suspected to be a precursor of invasive breast cancer (IBC). Our goal is the estimation of the age-specific and lifetime penetrances of DCIS among carriers of either a BRCA1 or BRCA2 deleterious mutation. We jointly re-analyze the SEER9 database and a previous study by Claus et al. (JAMA 293:964–969, 2005). Estimation is performed via Bayes theorem after the evaluation of the ratio of age-specific DCIS incidences, and extrapolation to the general population of the study-specific penetrance obtained from Claus et al. From the SEER9 database, we estimate the lifetime risk of DCIS to be 0.98 %, in contrast to value of 12.5 % usually reported for IBC. By extending the result in Claus et al. to the general population, we obtain a lifetime risk for carriers of a deleterious mutation of either BRCA1 or BRCA2 of 6.21 % (95 % CI 6.09–6.33 %). The increase in lifetime risk of DCIS for a BRCA mutation carrier compared to a non-carrier is therefore about six-fold. Our quantification is directly relevant to the identification and genetic counseling of BRCA mutation carriers, and emphasizes the potential importance of including information on diagnoses of DCIS in counseling of individuals who are at familial risk for breast cancer. All these factors can contribute to a more specific and targeted prevention, potentially reducing the impact of IBC among BRCA mutation carriers.     

Cancer worry among Norwegian male BRCA1/2 mutation carriers

This qualitative study explored the experiences of Norwegian men after being identified as BRCA 1/2 mutation-positive. Only limited knowledge is available on this topic; therefore, the aim of this study was to gain a deeper insight from the men’s own perspectives. Data were collected from in-depth interviews with 15 men and seven of their partners. The participants described fear of cancer development, and two main narrative patterns were identified: fear for their own health, including fear of developing cancer, and negative feelings about responsibility for others’ health. The men expressed fear of developing cancer themselves and described a need for genetic risk information. They were also deeply concerned about how the mutation might affect their children and other relatives. There is a need for guidelines concerning genetic risk information and follow-up programs for male BRCA 1/2 mutation carriers. This study adds valuable contextual insights into their experiences of living with fear of cancer.     

Cost‐effectiveness of alternating magnetic resonance imaging and digital mammography screening in BRCA1 and BRCA2 gene mutation carriers

BACKGROUND:

Current clinical guidelines recommend earlier, more intensive breast cancer screening with both magnetic resonance imaging (MRI) and mammography for women with breast cancer susceptibility gene (BRCA) mutations. Unspecified details of screening schedules are a challenge for implementing guidelines.

METHODS:

A Markov Monte Carlo computer model was used to simulate screening in asymptomatic women who were BRCA1 and BRCA2 mutation carriers. Three dual‐modality strategies were compared with digital mammography (DM) alone: 1) DM and MRI alternating at 6‐month intervals beginning at age 25 years (Alt25), 2) annual MRI beginning at age 25 years with alternating DM added at age 30 years (MRI25/Alt30), and 3) DM and MRI alternating at 6‐month intervals beginning at age 30 years (Alt30). Primary outcomes were quality‐adjusted life years (QALYs), lifetime costs (in 2010 US dollars), and incremental cost‐effectiveness (dollars per QALY gained). Additional outcomes included potential harms of screening, and lifetime costs stratified into component categories (screening and diagnosis, treatment, mortality, and patient time costs).

RESULTS:

All 3 dual‐modality screening strategies increased QALYs and costs. Alt30 screening had the lowest incremental costs per additional QALY gained (BRCA1, $74,200 per QALY; BRCA2, $215,700 per QALY). False‐positive test results increased substantially with dual‐modality screening and occurred more frequently in BRCA2 carriers. Downstream savings in both breast cancer treatment and mortality costs were outweighed by increases in up‐front screening and diagnosis costs. The results were influenced most by estimates of breast cancer risk and MRI costs.

CONCLUSIONS:

Alternating MRI and DM screening at 6‐month intervals beginning at age 30 years was identified as a clinically effective approach to applying current guidelines, and was more cost‐effective in BRCA1 gene mutation carriers compared with BRCA2 gene mutation carriers. Cancer 2013. © 2012 American Cancer Society.     

Bilateral risk-reducing oophorectomy in BRCA1 and BRCA2 mutation carriers

Bilateral risk-reducing oophorectomy (BRRO) is widely used for cancer risk reduction in women with BRCA1 and BRCA2 (BRCA1/2) mutations. BRRO significantly reduces breast cancer risk by approximately 50% and ovarian cancer risk by 85% to 95%, but it may be accompanied by menopausal symptoms, impaired quality of life, and accelerated bone loss. Therefore, decisions regarding the timing of BRRO, the risks and benefits of a simultaneous hysterectomy, and the use of hormone replacement therapy (HRT) must be made in concert with the patient and individualized to their circumstances. However, recent data demonstrate that HRT after BRRO in unaffected premenopausal women does not negate the breast cancer risk reduction that BRRO provides. This article reviews the studies regarding BRRO in BRCA1/2 mutation carriers, with particular focus on the use of HRT.     

Mammography screening and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers: a prospective study

Women with a genetic predisposition to breast cancer may be at increased risk of cancer after exposure to ionizing radiation. It is unclear whether mammography screening increases the risk of breast cancer among BRCA1 and BRCA2 carriers. We identified 2,346 women with a BRCA1 (n = 1844) or BRCA2 (n = 502) mutation and no breast cancer, and we reviewed their history of mammography exposure. These women were followed for an average of 5.3 years and were observed for new breast cancer diagnoses. At study entry, 1808 women (77.1 %) reported ever having had a mammogram; of these, 204 women (11.2 %) reported having had a mammogram before age 30. We estimated the hazard ratios for the development of invasive breast cancer, conditional on the number of prior mammograms and on the age at first mammogram. Hazard ratios were estimated and stratified by gene (BRCA1 or BRCA2), relative to women with no exposure. We observed no significant association between prior mammography exposure and breast cancer risk for BRCA1 carriers (HR 0.79; 95 % CI 0.53–1.19; P = 0.26) or for BRCA2 carriers (HR 0.90; 95 % CI 0.35–2.34; P = 0.83). An early age at first mammogram (<30 years) did not increase breast cancer risk among BRCA1 carriers (HR 0.75; 95 % CI 0.41–1.37; P = 0.35) or among BRCA2 carriers (HR 0.69; 95 % CI 0.19–2.48; P = 0.57). Exposure to mammography in women with BRCA1 and BRCA2 mutations is not associated with an increased risk of breast cancer.