Prevention of breast cancer in women who carry BRCA1 or BRCA2 mutations: a critical review of the literature

The purpose of our study was to review the evidence for the efficacy of surveillance for early detection, bilateral prophylactic mastectomy, prophylactic oophorectomy and chemoprevention in preventing breast cancer and improving survival of BRCA1 or BRCA2 carriers. A critical review of journal articles published between 1998 and 2004 identified by searches of MEDLINE, PubMed and references of retrieved articles was undertaken. None of the current evidence is based on randomized studies. The efficacy of surveillance for early detection of breast cancer among BRCA1 or BRCA2 carriers is not yet established. Screening with clinical breast examination and mammography showed lower sensitivity in BRCA1 or BRCA2 carriers than in the general population. Screening with MRI might offer higher sensitivity rates than mammography. Prophylactic mastectomy was shown to significantly reduce the risk of breast cancer by 89.5-100%. However, of all strategies reviewed, mastectomy was the least acceptable to women at high risk. Tamoxifen use was associated with breast cancer prevention among BRCA2 carriers (RR=0.38, 95%CI: 0.06-1.56). In BRCA1 or BRCA2 carriers with breast cancer, tamoxifen use was associated with the prevention of secondary breast cancer (OR= 0.50, 95% CI: 0.28-0.89). Prophylactic oophorectomy was associated with hazard ratios for breast cancer of 0.47 (95%CI:0.29-0.77) and 0.32 (95%CI: 0.08-1.20), in retrospective and short follow-up prospective cohort studies, respectively. There is a pressing need for more studies in order to determine which of the 4 strategies alone, or in combination, is the most effective for the prevention of breast cancer and for the improvement of survival of BRCA mutation carriers.     

Breast cancer risks in women with a family history of breast or ovarian cancer who have tested negative for a BRCA1 or BRCA2 mutation

Genetic testing for mutations in BRCA1 and BRCA2 is available in Canada for women with a significant family history of breast cancer. For the majority of tested women, a BRCA1 or BRCA2 mutation is not found, and counselling regarding breast cancer risk is based on the review of the pedigree. In this prospective study, we estimate breast cancer risks in women with a family history of breast cancer and for whom the proband tested negative for a mutation in BRCA1 or BRCA2. Families with two or more breast cancers under the age of 50 years, or with three cases of breast cancer at any age, and who tested negative for a BRCA1 or BRCA2 mutation were identified. Follow-up information on cancer status was collected on all first-degree relatives of breast cancer cases. The standardised incidence ratios (SIRs) for breast cancer were calculated by dividing the observed numbers of breast cancer by the expected numbers of breast cancers, based on the rates in the provincial cancer registries. A total of 1492 women from 365 families were included in the analyses. The 1492 first-degree relatives of breast cancer cases contributed 9109 person-years of follow-up. Sixty-five women developed breast cancer, compared to 15.2 expected number (SIR=4.3). The SIR was highest for women under the age of 40 (SIR=14.9) years and decreased with increasing age. However, the absolute risk was higher for women between the age of 50 and 70 (1% per year) years than for women between 30 and 50 (0.4% per year) years of age. There was no elevated risk for ovarian, colon or any other form of cancer. Women with a significant family history of breast cancer (ie, two or more breast cancers under the age of 50 years, or three or more breast cancers at any age), but who test negative for BRCA mutations have approximately a four-fold risk of breast cancer. Women in these families may be candidates for tamoxifen chemoprevention and/or intensified breast screening with an MRI.     

Prospective study of breast cancer risk for mutation negative women from BRCA1 or BRCA2 mutation positive families

Published studies have reached contradictory conclusions regarding breast cancer risk for women from families segregating a BRCA1 or BRCA2 mutation who do not carry the family-specific mutation. Accurate estimation of breast cancer risk is crucial for appropriate counselling regarding risk management. The aim of this study is to prospectively assess whether breast cancer risk for mutation negative women from families segregating BRCA1 or BRCA2 mutations is greater than for women in the general population. Eligible women were 722 first-, second- and third-degree relatives of a BRCA1 or BRCA2 mutation carrier from 224 mutation positive (128 BRCA1, 96 BRCA2) families, had no personal cancer history at baseline, and had been tested and found not to carry the family-specific mutation. Self-reported family history of cancer, preventive interventions and verified cancer diagnoses were collected at baseline, and every 3 years thereafter. Median follow-up was 6.1 years (range 0.1–12.4 years). Time at risk of breast cancer was censored at cancer diagnosis or risk-reducing surgery. Standardised incidence ratios (SIR) were estimated by comparing observed to population incidences of invasive breast cancer using Australian Cancer Incidence and Mortality Books. Six cases of invasive breast cancer were observed. The estimated SIRs were 1.14 (95% CI: 0.51–2.53) overall (n = 722), 1.29 (95% CI: 0.58–2.88) when restricted to first- and second-degree relatives of an affected mutation carrier (n = 442) and 0.48 (95% CI: 0.12–1.93) when restricted to those with no family history of breast cancer in the non-mutation carrying parental lineage (n = 424). There was no evidence that mutation negative women from families segregating BRCA1 or BRCA2 mutations are at increased risk of breast cancer. Despite this being the largest prospective cohort to assess this issue, moderately increased breast cancer risk (2-fold) cannot be ruled out.     

Risk reduction of contralateral breast cancer and survival after contralateral prophylactic mastectomy in BRCA1 or BRCA2 mutation carriers

The clinical outcome of contralateral prophylactic mastectomy (CPM) in women with a BRCA1 or BRCA2 mutation and a personal history of invasive breast cancer is unknown. We identified a cohort of 148 female BRCA1 or BRCA2 mutation carriers (115 and 33, respectively) who previously were treated for unilateral invasive breast cancer stages I-IIIa. In all, 79 women underwent a CPM, while the other women remained under intensive surveillance. The mean follow-up was 3.5 years and started at the time of CPM or at the date of mutation testing, whichever came last, that is, on average 5 years after diagnosis of the first breast cancer. One woman developed an invasive contralateral primary breast cancer after CPM, whereas six were observed in the surveillance group (P<0.001). Contralateral prophylactic mastectomy reduced the risk of contralateral breast cancer by 91%, independent of the effect of bilateral prophylactic oophorectomy (BPO). At 5 years follow-up, overall survival was 94% for the CPM group vs 77% for the surveillance group (P=0.03), but this was unexpectedly mostly due to higher mortality related with first breast cancer and ovarian cancer in the surveillance group. After adjustment for BPO in a multivariate Cox analysis, the CPM effect on overall survival was no longer significant. Our data show that CPM markedly reduces the risk of contralateral breast cancer among BRCA1 or BRCA2 mutation carriers with a history of breast cancer. Longer follow-up is needed to study the impact of CPM on contralateral breast cancer-specific survival. The choice for CPM is highly correlated with that for BPO, while only BPO leads to a significant improvement in overall survival so far.     

Effect of pregnancy as a risk factor for breast cancer in BRCA1/BRCA2 mutation carriers

Early age at first birth and multiparity have been associated with a decrease in the risk of breast cancer in women in the general population. We examined whether this relationship is also present in women at high risk of breast cancer due to the presence of a mutation in either of the 2 breast cancer susceptibility genes, BRCA1 or BRCA2. We performed a matched case-control study of 1,260 pairs of women with known BRCA1 or BRCA2 mutations, recruited from North America, Europe and Israel. Women who had been diagnosed with breast cancer were matched with unaffected control subjects for year of birth, country of residence, and mutation (BRCA1 or BRCA2). Study subjects completed a questionnaire detailing their reproductive histories. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived by conditional logistic regression. Among BRCA1 carriers, parity per se was not associated with the risk of breast cancer (OR for parous vs. nulliparous = 0.94; 95% CI = 0.75-1.19; p = 0.62). However, women with a BRCA1 mutation and 4 or more children had a 38% decrease in breast cancer risk compared to nulliparous women (OR = 0.62; 95% CI = 0.41-0.94). In contrast, among BRCA2 carriers, increasing parity was associated with an increased risk of breast cancer; women with 2 or more children were at approximately 1.5 times the risk of breast cancer as nulliparous women (OR = 1.53; 95% CI = 1.01-2.32; p = 0.05). Among women with BRCA2 mutations and who were younger than age 50, the (adjusted) risk of breast cancer increased by 17% with each additional birth (OR = 1.17; 95% CI = 1.01-1.36; p = 0.03). There was no significant increase in the risk of breast cancer among BRCA2 carriers older than 50 (OR for each additional birth = 0.97; 95% CI = 0.58-1.53; p = 0.92). In the 2-year period following a birth, the risk of breast cancer in a BRCA2 carrier was increased by 70% compared to nulliparous controls (OR = 1.70; 95% CI = 0.97-3.0). There was a much smaller increase in breast cancer risk among BRCA2 carriers whose last birth was 5 or more years in the past (OR = 1.24; 95% CI = 0.79-1.95). A modest reduction in risk of breast cancer was observed among BRCA1 carriers with 4 or more births. Among BRCA2 carriers, increasing parity was associated with a significant increase in the risk of breast cancer before age 50 and this increase was greatest in the 2-year period following a pregnancy.     

BRCA1 and BRCA2 mutation frequency in women evaluated in a breast cancer risk evaluation clinic.

PURPOSE: To determine the prevalence of BRCA1 and BRCA2 mutations in families identified in a breast cancer risk evaluation clinic. PATIENTS AND METHODS: One hundred sixty-four families seeking breast cancer risk evaluation were screened for coding region mutations in BRCA1 and BRCA2 by conformation-sensitive gel electrophoresis and DNA sequencing. RESULTS: Mutations were identified in 37 families (22.6%); 28 (17.1%) had BRCA1 mutations and nine (5.5%) had BRCA2 mutations. The Ashkenazi Jewish founder mutations 185delAG and 5382insC (BRCA1) were found in 10 families (6.1%). However, 6174delT (BRCA2) was found in only one family (0.6%) despite estimates of equal frequency in the Ashkenazi population. In contrast to other series, the average age of breast cancer diagnosis was earlier in BRCA2 mutation carriers (32.1 years) than in women with BRCA1 mutations (37.6 years, P =.028). BRCA1 mutations were detected in 20 (45.5%) of 44 families with ovarian cancer and 12 (75%) of 16 families with both breast and ovarian cancer in a single individual. Significantly fewer BRCA2 mutations (two [4.5%] of 44) were detected in families with ovarian cancer (P =.01). Eight families had male breast cancer; one had a BRCA1 mutation and three had BRCA2 mutations. CONCLUSION: BRCA1 mutations were three times more prevalent than BRCA2 mutations. Breast cancer diagnosis before 50 years of age, ovarian cancer, breast and ovarian cancer in a single individual, and male breast cancer were all significantly more common in families with BRCA1 and BRCA2 mutations, but none of these factors distinguished between BRCA1 and BRCA2 mutations. Evidence for reduced breast cancer penetrance associated with the BRCA2 mutation 6174delT was noted.     

Breast conservation in BRCA1 or BRCA2 mutation carriers with early stage breast cancer

The role of breast conservation therapy (limited surgery and irradiation of the breast with/without axilla) in the approximately 5% of breast cancer patients who harbour a germline mutation in BRCA1 or BRCA2, is a largely unexplored area and is seen by some as controversial. The relatively high cumulative risk of second primary cancers in such patients and concern about a possible decreased ability of mutation carriers to repair DNA damage caused by radiation has fuelled this controversy. Published studies of breast conservation therapy in carriers of a mutation in BRCA1 or BRCA2 are reviewed, with particular attention to their methodology. These studies have not demonstrated any increase in radiation sensitivity of normal tissues in mutation carriers, either in terms of increased early or late toxicity or tumourigenesis. Likewise, tumour sensitivity to radiotherapy, which might be expected based on the known functions of the BRCA1 and BRCA2 genes, has not been documented to date in mutation carriers. Further, methodologically rigorous studies of large numbers of breast cancer patients who carry a mutation in BRCA1 or BRCA2 are required to fully elucidate these issues.     

Uptake of risk-reducing salpingo-oophorectomy in women carrying a BRCA1 or BRCA2 mutation: evidence for lower uptake in women affected by breast cancer and older women

Background:

Bilateral risk-reducing salpingo-oophorectomy (BRRSO) is the only effective way of reducing mortality from ovarian cancer. This study investigates uptake of BRRSO in 700 BRCA1/2 mutation carriers from Greater Manchester.

Methods:

Dates of last follow-up and BRRSO were obtained, and the following variables were investigated: ovarian cancer risk/gene, age and breast cancer history. The date of the genetic mutation report was the initiation for Kaplan–Meier analysis.

Results:

The uptake of BRRSO in BRCA1 mutation carriers was 54.5% (standard error 3.6%) at 5 years post testing compared with 45.5% (standard error 3.2%) in BRCA2 mutation carriers (P=0.045). The 40–59 years category showed the greatest uptake for BRRSO and uptake was significantly lower in the over 60 s (P<0.0001). Of the unaffected BRCA1 mutation carriers, 65% (standard error 5.1%) opted for surgery at 5 years post-testing compared with 41.1% (standard error 5.1%) in affected BRCA1 mutation carriers (P=0.045).

Conclusion:

The uptake of BRRSO is lower in women previously affected by breast cancer and in older women. As there is no efficient method for early detection of ovarian cancer, uptake should ideally be greater. Counselling should be offered to ensure BRCA1/2 mutation carriers make an informed decision about managing their ovarian cancer risk.     

Humoral immune responses to MUC1 in women with a BRCA1 or BRCA2 mutation

IntroductionBreast cancer patients with early disease and a natural humoral response to MUC1 have a favourable prognosis, suggesting a possible role of MUC1 antibodies (ab) in controlling haematogenous tumour dissemination and outgrowth. The aim of the study was to evaluate humoral immune responses to MUC1 in women at hereditary high risk of breast cancer to investigate whether this immune response could play a role in the prevention of disease.Materials and methodsCA15.3 (U/mL), and IgG and IgM ab to MUC1 (arbitrary units per mL, Arb-U/mL) were measured in serum samples obtained from 422 women at hereditary high risk of breast/ovarian cancer, of whom 127 BRCA1/2 carriers, attending the Familial Cancer Clinic of the VU University Medical Centre, and from 370 age-matched healthy controls. Serum samples obtained from women who developed breast cancer (N = 12) or breast cancer recurrence (N = 17), and from women who underwent prophylactic mastectomy (N = 12) and had no breast lesions were also tested.ResultsCA15.3 ranked significantly higher in mutation carriers than in controls (P = 0.03). MUC1 IgG ab levels ranked significantly lower in BRCA1/2 mutation carriers than in controls (P = 0.003). MUC1 IgG levels were not significantly different (P = 0.53) between women who developed primary breast cancer (median 0.72 Arb-U/ml, range 0.52–2.44 Arb-U/ml) and women who underwent prophylactic mastectomy and had no breast lesions (median 1.04 Arb-U/ml, range 0.43–2.88 Arb-U/ml).ConclusionSerum levels of natural IgG ab to MUC1 are lower in BRCA1/2 mutation carriers than in healthy controls. Furthermore, in contrast to previous results in women with sporadic breast cancer, no elevated MUC1 IgG ab were seen in women at hereditary high risk who developed breast cancer. Prophylactic immunotherapy with MUC1 substrates may be a strategy to reduce the risk of breast cancer in BRCA1/2 mutation carriers, strengthening tumour immune surveillance.     

Survival from breast cancer in women with a BRCA2 mutation by treatment

Background The impact of various breast-cancer treatments on patients with a BRCA2 mutation has not been studied. We sought to estimate the impact of bilateral oophorectomy and other treatments on breast cancer-specific survival among patients with a germline BRCA2 mutation.Methods We identified 664 women with stage I–III breast cancer and a BRCA2 mutation by combining five different datasets (retrospective and prospective). Subjects were followed for 7.2 years from diagnosis to death from breast cancer. Tumour characteristics and cancer treatments were patient-reported and derived from medical records. Predictors of survival were determined using Cox proportional hazard models, adjusted for other treatments and for prognostic features.Results The 10-year breast-cancer survival for ER-positive patients was 78.9% and for ER-negative patients was 82.3% (adjusted HR = 1.23 (95% CI, 0.62–2.45, p = 0.55)). The 10-year breast-cancer survival for women who had a bilateral oophorectomy was 89.1% and for women who did not have an oophorectomy was 59.0% (adjusted HR = 0.45; 95% CI, 0.28–0.72, p = 0.001). The adjusted hazard ratio for chemotherapy was 0.83 (95% CI, 0.65–1.53: p = 0.56).Conclusions For women with breast cancer and a germline BRCA2 mutation, positive ER status does not predict superior survival. Oophorectomy is associated with a reduced risk of death from breast cancer and should be considered in the treatment plan.Subject terms: Targeted therapies, Breast cancer     

Effect of mammography on breast cancer risk in women with mutations in BRCA1 or BRCA2.

Women who carry mutations in either the BRCA1 or BRCA2 genes are at risk for early-onset breast cancer and are recommended to begin screening mammography at age 25 to 30 years. Results of in vitro and animal studies suggest that BRCA1/BRCA2 mutation carriers are hypersensitive to ionizing radiation and possibly to radiation-induced breast cancer. This study was undertaken to investigate the association of low-dose radiation exposure from mammograms with breast cancer status in BRCA mutation carriers. One hundred sixty-two female mutation carriers provided information at time of genetic testing about exposure to mammograms before enrollment. Using unconditional logistic regression, breast cancer status was not associated with number of mammograms received before diagnosis (affected women) or ascertainment [unaffected women; adjusted odds ratio (OR), 0.94; P = not significant]. A larger group of 213 women provided information about lifetime number of mammograms. There was no association between mammogram exposure and risk in the group as a whole (adjusted OR, 1.04; P = not significant), although there was a modest association in BRCA1 carriers (adjusted OR, 1.08; P = 0.03). These findings indicate that screening mammography is unlikely to be associated with a large increase in breast cancer risk in this population.     

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   

Contralateral mastectomy improves survival in women with BRCA1/2-associated breast cancer

BRCA1/2 mutation carriers with breast cancer are at high risk of contralateral disease. Such women often elect to have contralateral risk-reducing mastectomy (CRRM) to reduce the likelihood of recurrence. This study considers whether CRRM improves overall survival. 105 female BRCA1/2 mutation carriers with unilateral breast cancer who underwent CRRM were compared to controls (593 mutation carriers and 105 specifically matched) not undergoing CRRM and diagnosed between 1985 and 2010. Survival was assessed by proportional hazards models, and extended to a matched analysis using stratification by risk-reducing bilateral salpingo-oophorectomy (RRBSO), gene, grade and stage. Median time to CRRM was 1.1 years after the primary diagnosis (range 0.0–13.3). Median follow-up was 9.7 years in the CRRM group and 8.6 in the non-CRRM group. The 10-year overall survival was 89 % in women electing for CRRM (n = 105) compared to 71 % in the non-CRRM group (n = 593); p < 0.001. The survival advantage remained after matching for oophorectomy, gene, grade and stage: HR 0.37 (0.17–0.80, p = 0.008)—CRRM appeared to act independently of RRBSO. CRRM appears to confer a survival advantage. If this finding is confirmed in a larger series it should form part of the counselling procedure at diagnosis of the primary tumour. The indication for CRRM in women who have had RRBSO also requires further research.     

Prophylactic salpingo-oophorectomy in a series of 89 women carrying a BRCA1 or a BRCA2 mutation

BACKGROUND: Prophylactic salpingo-oophorectomy (SO), which is recommended in BRCA1/2 mutation carriers, still needs to be reappraised. METHODS: In all, 89 BRCA1/BRCA2 mutation carriers underwent SO between 1994-2004. Past medical and familial history, SO, results and survival after SO were analyzed. RESULTS: The series consisted of 56 BRCA1 and 33 BRCA2 mutation carriers. All but 1 had a family history of breast (BC) and/or ovarian cancer; 42 BRCA1 and 31 BRCA2 had a personal history of BC. The median age at SO was 44 (BRCA1) and 49.5 (BRCA2) years for women without previous BC (not significant) and 48 (BRCA1) and 53 BRCA2) years (P=.03) for women with previous BC. Occult ovarian (n=2) and/or fallopian (n=3) carcinomas were found in 4 patients (4.5%): 1 experienced recurrence (4 years), 2 are disease-free (26 and 38 months of follow-up), and 1 died from BC (12 months). Among the other 69 patients with previous BC (median follow-up, 42 months), 14 developed ipsilateral or contralateral BC and 8 developed metastatic disease. Among the 16 patients without previous BC (median follow-up, 27 months), 3 developed BC. Of the 89 patients, 85 are still alive: 3 died from BC and 1 died from pancreatic cancer. No peritoneal malignancy was observed. CONCLUSIONS: This study shows that prophylactic SO remains an important option for BRCA1/2 mutation carriers as asymptomatic ovarian/fallopian cancers were found in 4.5% of patients. However, a longer follow-up and larger series are required to more precisely evaluate the benefits of this procedure in terms of BC incidence, peritoneal malignancy, or recurrence.     

Use of genetic testing and prophylactic mastectomy and oophorectomy in women with breast or ovarian cancer from families with a BRCA1 or BRCA2 mutation.

PURPOSE: To analyze the use of genetic testing, prophylactic mastectomy, and oophorectomy among women with breast and/or ovarian cancer from families with a BRCA1 or BRCA2 mutation. PATIENTS AND METHODS: We examined prospectively the use of BRCA1/BRCA2 testing in all women with a primary breast or ovarian cancer from a consecutive series of 112 high-risk families in which a BRCA1/BRCA2 mutation eventually was identified. The rate of prophylactic bilateral and contralateral mastectomy and prophylactic oophorectomy was analyzed in the women who carried a BRCA1/BRCA2 mutation and who had no metastatic disease at the time of the genetic test disclosure. We examined predictors for genetic test uptake and prophylactic surgery using univariate and multivariate analysis. RESULTS: Overall, 192 of 220 women (87%) with primary tumors underwent genetic testing. Eleven of these 192 tested women (6%) appeared not to carry the family-specific BRCA1/BRCA2 mutation. Genetic testing occurred significantly more frequently at ages younger than 50 years (P =.04) and in persons with multiple primary tumors (P =.02). Among eligible women, 35 of 101 (35%) requested bilateral or contralateral mastectomy, and 47 of 95 (49%) requested oophorectomy. Women aged younger than 50 years and women who developed their first tumor after the initial identification of a BRCA1/BRCA2 mutation in the family were significantly (both P =.01) more likely to opt for prophylactic bilateral or contralateral mastectomy. CONCLUSION: In a clinical setting, we show a high demand for BRCA1/BRCA2 testing and for prophylactic surgery by women with breast and/or ovarian cancer from high-risk families.     

乳腺癌易感基因BRCA1和BRCA2的突变检测及其临床意义

乳腺癌易感基因BRCA1、BRCA2在家族性和遗传性乳腺癌中突变率较高.现就其功能、检测及临床应用方面的研究进展作一综述.     

Predictors of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers

Purpose:

The objective of this study was to estimate the risk of contralateral breast cancer in BRCA1 and BRCA2 carriers; and measure the extent to which host, family history, and cancer treatment-related factors modify the risk.

Patients and methods:

Patients were 810 women, with stage I or 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:

Overall, 149 subjects (18.4%) developed a contralateral breast cancer. The 15-year actuarial risk of contralateral breast cancer was 36.1% for women with a BRCA1 mutation and was 28.5% for women with a BRCA2 mutation. Women younger than 50 years of age at the time of breast cancer diagnosis were significantly more likely to develop a contralateral breast cancer at 15 years, compared with those older than 50 years (37.6 vs 16.8% P=0.003). Women aged <50 years with two or more first-degree relatives with early-onset breast cancer were at high risk of contralateral breast cancer, compared with women with fewer, or no first-degree relatives with breast cancer (50 vs 36% P=0.005). The risk of contralateral breast cancer was reduced with oophorectomy (RR 0.47; 95% CI 0.30–0.76; P=0.002).

Conclusion:

The risk of contralateral breast cancer risk in BRCA mutation carriers declines with the age of diagnosis and increases with the number of first-degree relatives affected with breast cancer. Oophorectomy reduces the risk of contralateral breast cancer in young women with a BRCA mutation.