Evaluation and management of women with BRCA1/2 mutations

Genetic counseling and testing for susceptibility to breast and ovarian cancer is often an integral component of management for women with a personal and/or family history of these malignancies. In this article, we will briefly review the function and genetic epidemiology of the two major susceptibility genes, BRCA1 and BRCA2. We will then address approaches to risk assessment for women at high risk with respect to the probability that they harbor a deleterious mutation in one of these genes, and the likelihood that they will develop cancer if such a mutation is identified. The process of genetic counseling and testing is discussed, including a summary of the potential benefits, limitations, and risks of testing as well as a summary of test result interpretation. We conclude with a review and appraisal of the various options for breast and ovarian cancer risk reduction and screening options for women with a BRCA1 or BRCA2 mutation.     

Predictive factors for BRCA1/BRCA2 mutations in women with ductal carcinoma in situ

BACKGROUND:

It is unclear whether women with ductal carcinoma in situ (DCIS), like their counterparts with invasive breast cancer, warrant genetic risk assessment and testing on the basis of high‐risk variables. The authors of this report identified predictive factors for mutations in the breast cancer‐susceptibility genes BRCA1 and BRCA2 in women who were diagnosed with DCIS.

METHODS:

One hundred eighteen women with DCIS who were referred for genetic counseling and underwent genetic testing for BRCA1/BRCA2 mutations between 2003 and 2010 were included in the study. Logistic regression models were fit to determine the associations between potential predictive factors and BRCA status.

RESULTS:

Of 118 high‐risk women with DCIS, 27% (n = 32) tested positive for BRCA1/BRCA2 mutations. Of those, 10% (n = 12) and 17% (n = 20) had BRCA1 and BRCA2 mutations, respectively. Age, race, and tumor characteristics did not differ between BRCA noncarriers and carriers. In a multivariate logistic model, ≥2 relatives with ovarian cancer (OC) (odds ratio [OR], 8.81; 95% confidence interval [CI], 1.38‐56.29; P = .034), and a score ≥10% according to the BRCAPRO mathematical model for calculating the probability that a particular family member carries a germline BRCA mutation (OR, 6.37; 95% CI, 2.23‐18.22; P = .0005) remained as independent significant predictors for a BRCA mutation. Fifty‐seven percent of mutation carriers but only 25% of noncarriers underwent prophylactic mastectomy(P = .0037). This difference remained significant for patients aged ≤40 years (P = .025).

CONCLUSIONS:

Women who had DCIS and a family history of OC or who had BRCAPRO scores ≥10% had a high rate of BRCA positivity regardless of age at diagnosis. These findings suggest that high‐risk patients with DCIS are appropriate candidates for genetic testing for BRCA mutations in the presence of predictive factors even if they do not have invasive breast cancer. Cancer 2011;. © 2011 American Cancer Society.     

Clinical management of women with genomic BRCA1 and BRCA2 mutations*

Purpose. There is increasing evidence that BRCA1 and BRCA2 associated tumors may differ from sporadic cancers. The purpose of this report is to review the current state of knowledge of BRCA1 and BRCA2, the biology of associated tumors, and possible risk reduction strategies in women with these deleterious mutations. Design and methods. We conducted an extensive literature search of all published articles (including Medline) on preclinical data on the function of BRCA1 and BRCA2, associated tumor pathology, and the clinical management for both unaffected carriers and affected patients. Results. BRCA1 and BRCA2 are likely to act as tumor suppressor genes, and together with RAD51 operate in a common DNA damage response pathway implicated in double-strand repair. Breast cancers associated with BRCA1 are frequently of a higher grade, steroid hormone receptor negative, and appear to have a higher proportion of atypical or typical medullary subtype. Conversely, BRCA2 associated breast cancers do not differ significantly from sporadic cancers. No special tumor phenotype has been ascribed to BRCA1 or BRCA2 associated ovarian cancers. Guidelines for risk reduction strategies for the high risk unaffected carrier have been recommended by expert panels in the USA and Europe. Lifestyle changes, multi-modality screening, chemoprevention, and prophylactic oophorectomy and mastectomy, with their possible benefits and attendant risks are described. Finally, locoregional and systemic treatment in breast and ovarian cancers associated with these mutations, and differences between these and sporadic cancers are discussed. Conclusions. Although the incidence of breast or ovarian cancers that can be attributed to BRCA1 or BRCA2 mutations account for less than 5% of all cancers, these cancers may differ from sporadic cases in terms of tumor biology and phenotype. These differences may impact directly on clinical management of breast and ovarian cancer patients, and their relatives. Further recommendations of these patients are constantly changing as new information emerges on the clinical behavior of these cancers.     

Catalysts towards cancer risk management action: A longitudinal study of reproductive-aged women with BRCA1/2 mutations

ABSTRACT

Deleterious mutations in BRCA1 or BRCA2 genes increase a woman's lifetime risk of breast and ovarian cancer. Risk management guidelines endorse early detection and prevention behaviors. Despite expressed intent, uptake of these measures remains low. This longitudinal, qualitative study integrated retrospective and prospective data to distinguish factors shaping intent to act from those that are catalysts to taking action to reduce cancer risk. Twelve BRCA1/2 mutation-positive women participating in the National Cancer Institute's Breast Imaging Study aged 18–35 completed two semi-structured interviews three years apart. Researchers completed focused coding to identify points of behavioral intent and action and contextual factors acting as catalysts upon participant narratives. All women shared only two action steps: seeking information about cancer risk and completing genetic testing. The constellation of action steps created a unique action trajectory that was defined, with precise ideas about risk perception and clear behavioral response, or iterative, in which unanticipated life events shifted the speed, accessibility, or order in which risk management and family planning goals were prioritized, planned, or executed. Factors shifting action steps included salient, unanticipated life events, such as infertility, insurance/financial constraints, birth of the last child, or a relative's cancer diagnosis. Focus on cancer morbidity may obfuscate how women prioritize actions, and ignore varied pragmatic, relational, and social factors affecting how intended actions are completed, particularly during the reproductive years. We recommend providers update patients' risk management plans at each visit to assess readiness for next steps and reduce reluctance to discuss, or guilt associated with, change.     

Diabetes and breast cancer among women with BRCA1 and BRCA2 mutations

BACKGROUND:

Hyperinsulinemia and the metabolic syndrome are both risk factors for breast cancer. It is not clear if diabetes is associated with the risk of breast cancer in women with a BRCA1 or BRCA2 mutation.

METHODS:

The authors reviewed the medical histories of 6052 women with a BRCA1 or BRCA2 mutation, half of whom had been diagnosed with breast cancer. They estimated the odds ratio for breast cancer, given a self‐report of diabetes. They then estimated the hazard ratio for a new diagnosis of diabetes associated with a history of breast cancer.

RESULTS:

There was no excess of diabetes in the period before the diagnosis of breast cancer, compared with controls with no diagnosis of breast cancer. The risk of diabetes was doubled among BRCA carriers in the 15‐year period after the diagnosis of breast cancer (relative risk, 2.0; 95% confidence interval [CI], 1.4‐2.8; P = .0001), compared with carriers without cancer. The risk was particularly high for women with a body mass index (BMI) >25.0 kg/m² (odds ratio, 5.8; 95% CI, 4.0‐8.6; P = .0001).

CONCLUSIONS:

After a diagnosis of breast cancer, women with a BRCA1 or BRCA2 mutation face a 2‐fold increase in the risk of diabetes, which is exacerbated by a high BMI. Cancer 2011. © 2010 American Cancer Society.     

BRCA1/BRCA2 germline mutations in locally recurrent breast cancer patients after lumpectomy and radiation therapy: implications for breast-conserving management in patients with BRCA1/BRCA2 mutations.

PURPOSE: Breast cancer patients treated conservatively with lumpectomy and radiation therapy (LRT) have an estimated lifetime risk of local relapse (ipsilateral breast tumor recurrence [IBTR]) of 10% to 15%. For breast cancer patients carrying BRCA1 or BRCA2 (BRCA1/2) mutations, the outcome of treatment with LRT with respect to IBTR has not been determined. In this study, we estimate the frequency of BRCA1/2 mutations in a study of breast cancer patients with IBTR treated with LRT. PATIENTS AND METHODS: Between 1973 and 1994, there were 52 breast cancer patients treated with LRT who developed an IBTR within the prior irradiated breast and who were willing to participate in the current study. From our database, we also identified 52 control breast cancer patients treated with LRT without IBTR. The control patients were individually matched to the index cases with respect to multiple clinical and pathologic parameters. Lymphocyte DNA specimens from all 52 locally recurrent patients and 15 of the matched control patients under age 40 were used as templates for polymerase chain reaction amplification and dye-primer sequencing of exons 2 to 24 of BRCA1, exons 2 to 27 of BRCA2, and flanking intron sequences. RESULTS: After LRT, eight (15%) of 52 breast cancer patients had IBTR with deleterious BRCA1/2 mutations. By age, there were six (40%) of 15 patients with IBTR under age 40 with BRCA1/2 mutations, one (9.0%) of 11 between ages 40 and 49, and one (3.8%) of 26 older than age 49. In comparison to the six (40%) of 15 of patients under age 40 with IBTR found to have BRCA1/2 mutations, only one (6.6%) of 15 matched control patients without IBTR and had a BRCA1/2 mutation (P =.03). The median time to IBTR for patients with BRCA1/2 mutations was 7.8 years compared with 4.7 years for patients without BRCA1/2 mutations (P =.03). By clinical and histologic criteria, these relapses represented second primary tumors developing in the conservatively treated breast. All patients with BRCA1/2 mutations and IBTR underwent successful surgical salvage mastectomy at the time of IBTR and remain alive without evidence of local or systemic progression of disease. CONCLUSION: In this study, we found an elevated frequency of deleterious BRCA1/2 mutations in breast cancer patients treated with LRT who developed late IBTR. The relatively long time to IBTR, as well as the histologic and clinical criteria, suggests that these recurrent cancers actually represent new primary breast cancers. Early onset breast cancer patients experiencing IBTR have a disproportionately high frequency of deleterious BRCA1/2 mutations. This information may be helpful in guiding management in BRCA1 or BRCA2 patients considering breast-conserving therapy.     

The quality of life associated with prophylactic treatments for women with BRCA1/2 mutations.

PURPOSE: This study was conducted to obtain and compare the preferences assigned to cancer states and prevention measures by women who had breast cancer, were at high risk for breast cancer, or had neither condition. PATIENTS AND METHODS: We administered a time trade-off questionnaire to 21 breast cancer patients, 28 women with a personal history of multiple breast biopsies or a family history of breast cancer, and 135 women without these conditions (the reference group). We stratified the reference group into two groups aged 20 to 32 years and 33 to 50 years, respectively. RESULTS: All four groups assigned higher preference to breast cancer than to ovarian cancer. Both reference groups preferred using a tamoxifen-like drug to having mastectomy or oophorectomy for cancer prevention; the high-risk and breast cancer groups did not. None of the four groups had a preference between prophylactic mastectomy and breast cancer. All the groups were willing to subtract more years from their life expectancy to protect offspring from genetic risk than to protect themselves. Reference group members in the 33- to 50-year age range had lower mean ratings than the breast cancer group for almost all the health states, and breast cancer patients were less willing than other respondents to trade time for health. Most of these differences were not statistically significant. The high-risk group was similar to the older reference group in time trade-off ratings. DISCUSSION: The time trade-off-based preferences of healthy women may be used to predict the treatment preferences of women with BRCA1/2 mutations. Obtaining healthy women's ratings of treatment outcomes may help health care policy makers envision the consequences of the difficult choices that high-risk women face.     

BRCA1 and BRCA2 mutations in women from Shanghai China.

Little is known about the frequency of germ-line mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 among Asian populations. We investigated the distribution of BRCA1 and BRCA2 germ-line mutations and polymorphisms in a cohort of women from Shanghai, China. Study subjects totaled 1306, and included 645 women with breast cancer, 342 women with benign breast disease, and 319 unaffected controls, born between 1924 and 1958, selected from women enrolled in a randomized trial of Breast Self-Examination in Shanghai, China. Women were selected without regard to family history of breast or ovarian cancer. All of the coding regions and exon-intron boundaries were screened. Data were analyzed with respect to age at diagnosis, and family history of breast and ovarian cancer. The prevalence of known disease-associated mutations in women with breast cancer was 1.1% each, for BRCA1 and BRCA2. Among breast cancer cases with a family history of breast or ovarian cancer, 8.1% and 2.7% carried likely BRCA1 and BRCA2 disease-associated mutations, respectively. Overall, these results suggest that inherited susceptibility to breast cancer due to germ-line BRCA1/2 mutations among women with a family history of breast cancer is comparable between women from Shanghai and Caucasian women of Western European descent. Most alterations observed appear unique to the Chinese population, suggesting a resource that will be useful for assessing risk among both Chinese women and United States women of Chinese descent.     

Reproductive issues for women with BRCA mutations

Women carrying BRCA1 and BRCA2 mutations face difficult and confusing reproductive decisions that fall into three categories: issues relating to risk-reducing surgeries, issues relating to use of oral contraceptives/tubal ligation, and issues relating to pregnancy and breastfeeding. Risk-reducing surgeries may confer survival benefits, but they also affect quality of life. Oral contraceptives potentially protect mutation carriers against ovarian cancer but increase the risk of early-onset breast cancer, and evidence for the efficacy of tubal ligation in reducing ovarian cancer risk in BRCA mutation carriers is contradictory. Women with BRCA mutations may increase their risk of breast cancer by becoming pregnant before age 40 years, but breastfeeding may decrease risk of breast cancer in women with BRCA mutations, regardless of age. BRCA mutation carriers desiring to become pregnant must deal with a variety of psychosocial issues, some with significant ethical implications, with minimal guidance from research.     

Family history of cancer and cancer risks in women with BRCA1 or BRCA2 mutations

Women who carry a deleterious mutation in BRCA1 or BRCA2 have high lifetime risks of breast and ovarian cancers. However, the influence of a family history of these cancers on these risks in women with BRCA mutations is unclear. We calculated cancer incidence rates for a multinational cohort comprising 3011 women with BRCA1 or BRCA2 mutations who were followed up for a mean of 3.9 years, during which time 243 incident breast or ovarian cancers were recorded. The 10-year cumulative risks of breast cancer were 18.1% (95% confidence interval [CI] = 13.3% to 22.8%) for women with a BRCA1 mutation and 15.2% (95% CI = 9.1% to 21.2%) for women with a BRCA2 mutation. Among women with a BRCA1 mutation, the risk of breast cancer increased by 1.2-fold for each first-degree relative with breast cancer before age 50 years (hazard ratio [HR] = 1.21; 95% confidence interval [CI] = 0.94 to 1.57) and the risk of ovarian cancer increased by 1.6 fold for each first- or second-degree relative with ovarian cancer (HR = 1.61; 95% CI = 1.21 to 2.14). Among women with a BRCA2 mutation, the risk of breast cancer increased by 1.7-fold for each first-degree relative younger than 50 years with breast cancer (HR = 1.67; 95% CI = 1.04 to 2.07).     

Breast cancer surveillance in women with hereditary risk due to BRCA1 or BRCA2 mutations

Women with germline mutations in BRCA1 or BRCA2 are known to be at substantially elevated risk for breast cancer. With increasing acceptance of genetic testing, significant numbers of mutation carriers are being identified, but evidence-based guidelines for the management of women at hereditary risk are lacking. This article reviews the most commonly recommended modalities employed in breast cancer surveillance for women at increased risk. It is apparent that the standard techniques of breast self-examination, clinical breast examination, and mammography are suboptimal for the identification of hereditary breast cancer. At least half of the cancers in this population appear to be detected by physical examination in the intervals between routine radiographic surveillance. Host factors (eg, breast density) and tumor features (rapid proliferative rates) likely contribute to the relative insensitivity of mammography. These factors may be mitigated by the deployment of screening techniques for breast cancer such as ultrasound and magnetic resonance imaging. However, the effect of incremental screening on either stage at diagnosis or breast cancer mortality has not been defined. In addition, the impact of the relatively limited specificity of these techniques on the quality of life (QOL) of women at risk has not been studied. Further research is needed to evaluate the effect of incremental radiographic screening on outcomes, to delineate the best way to integrate the different modalities in terms of sequencing and frequency, and to identify interventions that will minimize the impact of intensive surveillance programs on the QOL of the women engaged in them.     

Occult ovarian tumors in women with BRCA1 or BRCA2 mutations undergoing prophylactic oophorectomy.

PURPOSE: To review the findings at prophylactic oophorectomy of a series of women who presented to a familial breast and ovarian cancer clinic. MATERIALS AND METHODS: Data from medical charts, operative notes, and pathology reports were collected on women who had undergone prophylactic oophorectomies because of the elevated risk of ovarian cancer. Because only a subset of patients underwent BRCA1 and BRCA2 testing, each patient's risk of hereditary predisposition was calculated using the Berry-Parmigiani model and family history data. RESULTS: From June 1989 to December 1998, 50 women seen at our clinic underwent prophylactic oophorectomy, 33 of whom had a calculated risk of carrying a germline BRCA1 or BRCA2 mutation greater than 25%. Among this group, four incidental tumors were found (four of 33, or 12%); one tumor was noted at the time of surgery and three were noted only in the final pathology. Two patients had microscopic, poorly differentiated serous adenocarcinomas in multiple sites on both ovaries. A third patient had a bilateral serous borderline tumor with micropapillary features. The fourth patient had a microscopic serous borderline ovarian tumor. All four patients had germline BRCA1 or BRCA2 mutations, and three had unremarkable transvaginal ultrasonography examinations within 6 months before prophylactic surgery. CONCLUSION: Foci of malignant tumor are not uncommon in prophylactic oophorectomies performed in women at very high risk for ovarian cancer and may not be detected on ultrasonograms. Surgeons should have a high suspicion of finding cancer in these women at the time of prophylactic surgery, and careful pathologic assessment of the specimens should be conducted.     

Breast cancer risk factors differ between Asian and white women with BRCA1/2 mutations

The prevalence and penetrance of BRCA1 and BRCA2 (BRCA1/2) mutations may differ between Asians and whites. We investigated BRCA1/2 mutations and cancer risk factors in a clinic-based sample. BRCA1/2 mutation carriers were enrolled from cancer genetics clinics in Hong Kong and California according to standardized entry criteria. We compared BRCA mutation position, cancer history, hormonal and reproductive exposures. We analyzed DNA samples for single-nucleotide polymorphisms reported to modify breast cancer risk. We performed logistic regression to identify independent predictors of breast cancer. Fifty Asian women and forty-nine white American women were enrolled. BRCA1 mutations were more common among whites (67 vs. 42?%, p?=?0.02), and BRCA2 mutations among Asians (58 vs. 37?%, p?=?0.04). More Asians had breast cancer (76 vs. 53?%, p?=?0.03); more whites had relatives with breast cancer (86 vs. 50?%, p?=?0.0003). More whites than Asians had breastfed (71 vs. 42?%, p?=?0.005), had high BMI (median 24.3 vs. 21.2, p?=?0.04), consumed alcohol (2 drinks/week vs. 0, p?<?0.001), and had oophorectomy (61 vs. 34?%, p?=?0.01). Asians had a higher frequency of risk-associated alleles in MAP3K1 (88 vs. 59?%, p?=?0.005) and TOX3/TNRC9 (88 vs. 55?%, p?=?0.0002). On logistic regression, MAP3K1 was associated with increased breast cancer risk for BRCA2, but not BRCA1 mutation carriers; breast density was associated with increased risk among Asians but not whites. We found significant differences in breast cancer risk factors between Asian and white BRCA1/2 mutation carriers. Further investigation of racial differences in BRCA1/2 mutation epidemiology could inform targeted cancer risk-reduction strategies.