Genotype in BRCA‐associated Breast Cancers

Women with BRCA1 or 2 mutations are at high risk for breast cancer. For BRCA1, a trend of increasing risk has been associated with increasing downstream (3′) location for mutations compared to the upstream (5′) mutations in the gene. For BRCA2, an increased risk of breast cancer has been associated with mutations outside of the ovarian cancer cluster region (OCCR). We sought to determine the mutation position in BRCA‐associated breast cancers and whether or not there was a genotype‐phenotype correlation. Breast cancer patients with BRCA1/2 mutations were identified by a search of a prospectively maintained data base. Mutation site, patient, and tumor characteristics were determined through retrospective review. One hundred and sixty‐four patients with BRCA1‐associated breast cancer and 109 patients with BRCA2‐associated breast cancer were identified. Among patients with BRCA1‐associated cancers, 86 (52%) had mutations in the 5′ half of the gene. Among patients with BRCA2‐associated breast cancers, 40 (37%) had OCCR mutations. Although BRCA1‐associated tumors were more likely to be ER/PR‐ than BRCA2‐associated cancers (p < 0.0001), there was no difference in the tumor characteristics among BRCA1 or BRCA2‐associated cancers based on mutation location. In this single‐institution study, over half of BRCA1‐associated and over a third of BRCA2‐associated breast cancers were associated with putative lower risk mutations. Although we cannot exclude the possibility that mutations in these regions confer a lower relative risk for breast cancer, vigilance in cancer screening and prevention remains necessary. Further studies in genotype/phenotype correlation are needed to individualize prevention strategies.     

Early Onset Breast Cancer in a Registry‐based Sample of African‐American Women: BRCA Mutation Prevalence,and Other Personal and System‐level Clinical Characteristics

Young Black women are disproportionately afflicted with breast cancer, a proportion of which may be due to BRCA1 and BRCA2 (BRCA) gene mutations. In a sample of Black women with early onset breast cancer, we evaluated BRCA mutations and explored personal and system‐level clinical characteristics. Black women diagnosed with invasive breast cancer (age ≤50) were recruited through the state cancer registry. Participants completed a questionnaire, genetic counseling and BRCA testing. Of the 48 women who consented to study participation, 46 provided a usable biologic specimen for BRCA testing. The overall prevalence of BRCA mutations and variants of uncertain significance (VUS) in participants was 6.5% and 34.8%, respectively. Of these, only 14 were referred for genetic counseling prior to study enrollment. Overall, those participants who chose to undergo bilateral mastectomy had a higher number of relatives with breast and ovarian cancer (p = 0.024) and a higher household income (p = 0.009). BRCA mutation prevalence and the high prevalence of VUS in participants are consistent with prior studies. Furthermore, clinical factors such as family history and financial means may influence type of surgery recommended and chosen, at both the provider and patient level, respectively. Finally, the limited number of patients referred for genetic counseling prior to surgical treatment for breast cancer may represent a missed clinical opportunity to inform surgical decisions.     

Considerations for Comprehensive Assessment of Genetic Predisposition in Familial Breast Cancer

About 10–15% of breast cancer cases are family related, classified as familial breast cancer. The disease was first reported in 1866 and determined to be an autosomal dominant genetic disease in 1971. Germline mutations in BRCA1 were discovered and deemed as the first genetic predisposition for the disease in 1994. By now, genetic predispositions for about 40% of familial breast cancer families have been identified. New molecular genetic approaches currently under development should accelerate the process to identify the full spectrum of genetic predispositions for the disease, thereby enabling a better understanding of the genetic basis of the disease and therein providing benefit to high‐risk patients.     

Genotype–Phenotype Correlations by Ethnicity and Mutation Location in BRCA Mutation Carriers

The genotype–phenotype correlations of the specific BRCA1 and BRCA2 mutations in multi‐ethnic populations in USA have not yet been fully investigated. This study was designed to evaluate the effects of ethnicity at specific mutation locations and breast/ovarian cancer phenotypes. Our cohort included 445 women with different ethnic backgrounds who underwent BRCA genetic testing between 1997 and 2010. Known clinical and pathologic characteristics were compared with Chi‐Square Analysis or Fisher's Exact test as appropriate. The three most common mutation locations in BRCA1 (exons 2, 11, and 20) and BRCA2 (exons 10, 11, and 25) genes were chosen. Prevalence of BRCA1 exon 2 mutations were significantly higher in Ashkenazi Jewish (AJ) women compared to Caucasians (41% versus 15%; p = 0.001). Similarly, AJ women with breast cancer were more likely to have BRCA1 exon 2 mutation (47% positivity in AJ women versus 0–12.5% positivity in other ethnicities; p = 0.004). Women carrying the exon 20 BRCA1 mutation had the highest probability of having combined breast and ovarian cancers compared to women carrying other exon mutations (p = 0.05). The median age at initial cancer diagnosis, phenotypic features of breast cancer tumors, and overall survival did not vary significantly by ethnicity or mutation location. Our data suggest that ethnicity does not affect age of onset, overall survival or confer different risks of breast and ovarian cancer development in BRCA carriers. These results also suggest that women carrying the exon 20 BRCA1 mutation may warrant mutation‐specific counseling and be more aggressively managed for risk reduction.     

Alcohol consumption and the risk of breast cancer among BRCA1 and BRCA2 mutation carriers

Alcohol consumption increases the risk of breast cancer among women in the general population, but its effect on women who carry a BRCA gene mutation is unclear. We conducted a case-control study of 1925 matched pairs of predominantly premenopausal women who carry a BRCA1 or a BRCA2 mutation. Information on current alcohol consumption was obtained from a questionnaire administered during the course of genetic counselling or at the time of enrolment. A modest inverse association between breast cancer and reported current alcohol consumption was observed among women with a BRCA1 mutation (OR = 0.82, 95% CI 0.70–0.96), but not among women with a BRCA2 mutation (OR = 1.00; 95% CI 0.71–1.41). Compared to non-drinkers, exclusive consumption of wine was associated with a significant reduction in the risk of breast cancer among BRCA1 carriers (p-trend = 0.01). Alcohol consumption does not appear to increase breast cancer risk in women carrying a BRCA gene mutation.     

Germline BRCA mutation does not prevent response to taxane-based therapy for the treatment of castration-resistant prostate cancer

Study Type – Prognosis (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? In the preclinical setting BRCA mutations appear to modulate response to chemotherapy, increasing sensitivity to platinums and increasing resistance to taxanes. Clinical data supports a greater platinum sensitivity among BRCA mutation carriers. This study suggests that BRCA mutation carriers may also respond to taxanes.

OBJECTIVE

? To investigate the relationship between BRCA mutation status and response to taxane‐based chemotherapy, since BRCA mutation carriers with prostate cancer appear to have worse survival than non‐carriers and docetaxel improves survival in patients with castration‐resistant prostate cancer.

PATIENTS AND METHODS

? We determined BRCA mutation prevalence in 158 Ashkenazi Jewish (AJ) men with castration‐resistant prostate cancer. Clinical data were collected as part of an institutional prostate cancer research database and through additional medical record review. ? Clinical records and DNA samples were linked through a unique identifier, anonymizing the samples before genetic testing for the AJ BRCA1/2 founder mutations. ? Response to taxane‐based therapy was defined by the prostate‐specific antigen nadir within 12 weeks of therapy.

RESULTS

? In all, 88 men received taxane‐based treatment, seven of whom were BRCA carriers (three BRCA1, four BRCA2; 8%). Initial response to taxane was available for all seven BRCA carriers and for 69 non‐carriers. ? Overall, 71% (54/76) of patients responded to treatment, with no significant difference between carriers (57%) and non‐carriers (72%) (absolute difference 15%; 95% confidence interval –23% to 53%; P= 0.4). ? Among patients with an initial response, the median change in prostate‐specific antigen was similar for BRCA carriers (?63%, interquartile range ?71% to ?57%) and non‐carriers (?60%, interquartile range ?78% to ?35%) (P= 0.6). ? At last follow‐up, all seven BRCA carriers and 49 non‐carriers had died from prostate cancer. One BRCA2 carrier treated with docetaxel plus platinum survived 37 months.

CONCLUSION

? In this small, hypothesis‐generating study approximately half of BRCA carriers had a prostate‐specific antigen response to taxane‐based chemotherapy, suggesting that it is an active therapy in these individuals.     

Uptake of risk‐reducing surgery in BRCA gene carriers in Wales,UK

Women who inherit a mutated copy of the BRCA gene have a higher lifetime risk of developing breast cancer. No large epidemiological studies exist looking at BRCA mutation carriers in UK populations. All patients with BRCA1/BRCA2 mutation identified between 1995 and 2015 were included. Individuals were identified from a prospectively gathered data base. Genetics case‐notes were obtained and retrospective analysis performed. 581 female BRCA mutation carriers were identified with a median age of 34 (18‐81) at the time of testing. Of the 301 women who underwent diagnostic testing (symptomatic) 246 had been diagnosed with breast cancer, 89 with ovarian cancer and 37 had both at time of testing. Median age at diagnostic test was 51 (25‐81). 33% of women underwent risk‐reducing mastectomies (RRM); median age at surgery 45. This compares with 37% of women in this diagnostic group who underwent Risk‐reducing bilateral salpingo‐oopherectomies (RRBSO) at a median age of 46. Two hundred and eighty women underwent predictive testing (family history, asymptomatic), median age 36 (18‐81). 34% of women in this predictive group underwent RRM, median age 37. There was a 29% uptake of RRBSO (median age 44 years). Fifteen women (5%) developed breast cancer after being tested; none of these had undergone RRS. This unique study of all BRCA mutation carriers in Wales shows considerable variation in uptake of RRS. The decision to undergo RRS is complex and involves a number of factors, including a woman's age and life stage. As BRCA testing becomes more frequent and more gene mutation carriers are identified there will be significant implications for service allocation, screening demands, and provision of risk‐reducing surgery for this high‐risk patient group.     

Practical aspects of genetic counseling in breast cancer: Lights and shadows

In unselected populations, less than 10% of breast cancers are associated with germline mutations in predisposing genes. Breast cancer type 1 and 2 (BRCA1 and BRCA2) susceptibility genes are the most common involved genes and confer a 10–30 times higher risk of developing the disease compared to the general population. A personal or family history suggestive of inherited breast cancer syndrome may be further evaluated to assess the risk of genetic predisposition and the presence of a genetic mutation. Breast cancer genetic counseling should include a careful risk assessment with associated psychosocial evaluation and support, possible molecular testing, personalized discussion of results. Knowledge of BRCA status can influence individualized cancer risk-reduction strategies. i.e. active surveillance, prophylactic surgery and/or pharmacoprevention.     

Benchmarking of a checklist for the identification of familial risk for breast and ovarian cancers in a prospective cohort

The detection of deleterious germline mutations in BRCA1 and BRCA2 considerably influences the clinical management of healthy and diseased carriers. Therefore, the identification of persons at risk who could uptake genetic counseling and testing is pivotal. We developed a checklist with validated criteria to improve the identification, and prospectively evaluate the incidence, of familial cancer history in 5091 breast cancer patients. The rate of 30.4% of patients at high genetic risk underpins the demand for care in risk identification and counseling. The easy‐to‐use instrument promotes the implementation and dissemination of risk counseling by physicians.     

Heterogenic Loss of the Wild-Type BRCA Allele in Human Breast Tumorigenesis

Background For individuals genetically predisposed to breast and ovarian cancer through inheritance of a mutant BRCA allele, somatic loss of heterozygosity affecting the wild-type allele is considered obligatory for cancer initiation and/or progression. However, several lines of evidence suggest that phenotypic effects may result from BRCA haploinsufficiency. Methods Archival fixed and embedded tissue specimens from women with germ line deleterious mutations in BRCA1 or BRCA2 were identified. After pathologic review, focal areas of normal breast epithelium, atypical ductal hyperplasia, ductal carcinoma-in-situ, and invasive ductal carcinoma were identified from 14 BRCA1-linked and 9 BRCA2-linked breast cancers. Ten BRCA-linked prophylactic mastectomy specimens and 12 BRCA-linked invasive ovarian carcinomas were also studied. Laser catapult microdissection was used to isolate cells from the various pathologic lesions and corresponding normal tissues. After DNA isolation, real-time polymerase chain reaction assays were used to quantitate the proportion of wild-type to mutant BRCA alleles in each tissue sample. Results Quantitative allelotyping of microdissected cells revealed a high level of heterogeneity in loss of heterozygosity within and between preinvasive lesions and invasive cancers from BRCA1 and BRCA2 heterozygotes with breast cancer. In contrast, all BRCA-associated ovarian cancers displayed complete loss of the wild-type BRCA allele. Conclusions These data suggest that loss of the wild-type BRCA allele is not required for BRCA-linked breast tumorigenesis, which would have important implications for the genetic mechanism of BRCA tumor suppression and for the clinical management of this patient population.     

Earlier Age of Breast Cancer Onset in Israeli BRCA Carriers—Is it a Real Phenomenon?

Data on genetic anticipation in breast cancer are sparse. We sought to evaluate age at diagnosis of breast cancer in daughters with a BRCA mutation and their mothers. A review of all carriers of the BRCA mutation diagnosed with breast cancer at the Genetics Institute of a tertiary medical center in 2000–2013 yielded 80 women who could be paired with a mother with breast cancer who was either a carrier of the BRCA mutation or an obligate carrier according to pedigree analysis. Age at diagnosis, type of mutation (BRCA1, BRCA2), year of birth, and ethnicity were recorded. Paired t‐test was used to analyze differences in age at cancer diagnosis between groups and subgroups. Mean age at diagnosis of breast cancer was 50.74 years (range 22–88) in the mothers and 43.85 years (range 24–75) in the daughters. The difference was statistically significant (p < 0.001). These findings were consistent regardless of type of BRCA mutation, ethnicity, or mother's year of birth. However, on separate analysis of pairs in which the mother was diagnosed before the age of 50 years, there was no significant difference in mean age at diagnosis between mothers and daughters (~42 years for both). Daughters who carry a BRCA mutation are diagnosed with breast cancer at an earlier age than their carrier mothers, with the exception of pairs in which the mother was diagnosed before the age of 50 years. Future breast‐screening guidelines may need to target specific subpopulations of BRCA mutation carriers.     

BRCA mutation characteristics in a series of index cases of breast cancer selected independent of family history

Certain genetic predisposition factors, such as BRCA1 and BRCA2 mutations play a pivotal role in familial breast cancer development in both males and females. Due to this, the importance and necessity of genetic screening to identify mutations affecting the population is paramount. Undergoing genetic screenings allows for a more knowledgeable risk assessment for the patients and their care providers. The aim of this study was to evaluate the prevalence of BRCA1/BRCA2 mutated genes in the Turkish population among unselected patients. To identify the molecular markers, we utilized a gene panel analysis consisting of BRCA1 and BRCA2 genes, with a next generation sequencing platform (MiSeq System, Illumina). Sequencing was performed using leukocyte DNA from breast cancer patients. In‐silico analysis for novel mutations was carried out using SIFT, PolyPhen2 and MutationTaster. BRCA1 and BRCA2 pathogenic variants were identified in 18 of 129 (14%) patients among the study population; of those 18 patients, seven (39%) were found in the BRCA1 gene and 11 (61%) in the BRCA2 gene. Ten of the eleven BRCA2 variants (90%) were novel mutations. Four of ten (40%) of the novel mutations were determined to be deleterious and six out of ten (60%) were identified as single nucleotide variations. Clinically significant mutations of the BRCA1/BRCA2 genes are related to an increased susceptibility for breast cancer. There is however, little known about BRCA mutations amongst the general population. Thus, it is important that patients are able to undergo genetic screenings and counseling. This also allows for greater care from health care providers and can only facilitate disease prevention which in turn can lead to a decreased cancer morbidity rate.     

The Impact of Mental Illness on Uptake of Genetic Counseling for Hereditary Breast Cancer and Ovarian Cancer in a Multiethnic Cohort of Breast Cancer Patients

We evaluated whether mental illness is a barrier to genetic counseling for hereditary breast and ovarian cancer (HBOC) in multiethnic breast cancer patients. We conducted a retrospective analysis of 308 women with newly diagnosed breast cancer and eligible for HBOC genetic testing seen in the breast clinic of an academic, urban medical center from 2007 to 2015. Uptake of genetic services and history of mental health disorder (MHD), defined as a psychiatric diagnosis or treatment with an antidepressant, mood stabilizer, anxiolytic, or antipsychotic medication, were ascertained by medical chart review. The mean age at breast cancer diagnosis was 56 years, with 44% non‐Hispanic whites, 37% Hispanics, and 15% non‐Hispanic blacks. Ninety‐nine (32%) women met study criteria for MHD, 73% had a genetics referral, 57% had genetic counseling, and 54% completed BRCA testing. Uptake of genetic counseling services did not differ by race/ethnicity or presence of MHD. In multivariable analysis, younger age at diagnosis, Ashkenazi Jewish heritage, and family history of breast cancer were associated with HBOC genetic counseling. A relatively high proportion of breast cancer patients eligible for HBOC genetic testing were referred to a genetic counselor and referral status did not vary by MHD or race/ethnicity.     

Efficacy of anthracycline/taxane‐based neo‐adjuvant chemotherapy on triple‐negative breast cancer in BRCA1/BRCA2 mutation carriers

This study aims to estimate the pathologic complete response (pCR) rate after neo‐adjuvant chemotherapy and to compare disease‐free survival (DFS) and overall survival (OS) between pCR and non‐pCR groups of patients with triple‐negative breast cancer (TNBC) and deleterious BRCA1 or BRCA2 mutation. We carried out a retrospective analysis of 53 patients including 46 BRCA1, 6 BRCA2, and 1 combined BRCA1 and BRCA2 mutation. All patients had been diagnosed with triple‐negative breast cancer (TNBC) between 1997 and 2014. Neo‐adjuvant therapy consisted of regimens that were based on anthracycline or an anthracycline‐taxane doublet. DFS included any relapse or second cancer. The Kaplan‐Meier method and the log‐rank test were used to compare pCR and non‐pCR groups. A pCR was observed in 23 (42.6% [95% CI, 29.2%‐56.8%]) of the TNBC included. The pCR rate was 38.3% [95% CI, 26%‐55%] among BRCA1 mutation carriers, and 66% among the 6 BRCA2 mutation carriers. Median follow‐up was 4.4 years (range 0.62‐16.2 years) and did not differ between the groups (P = .25). Fifteen relapses and six second cancers were recorded during the follow‐up period. Eleven deaths occurred, all of which were in the non‐pCR group. DFS (P < .01) and OS (P < .01) were significantly better in the pCR group than the non‐pCR group. This study shows a high pCR rate after neo‐adjuvant therapy in BRCA‐mutated triple‐negative breast cancer, and the survival results confirm the prognostic value of pCR in this group. These outcomes should be considered as a basis of comparison to be used by future studies about new therapies in this domain.     

Management of breast cancer risk in BRCA1/2 mutation carriers who are unaffected with cancer

Pathogenic mutations in BRCA1 and BRCA2 genes markedly increase the risk of breast cancer and other cancers such as ovarian/fallopian tube, pancreatic, prostate, and melanoma. Patients with BRCA1 mutations have a slightly higher lifetime risk of breast cancer than BRCA2 mutation carriers, and both BRCA1 and BRCA2 carriers tend to develop breast cancer at an earlier age than the general population. In this review, we will discuss management recommendations to reduce breast cancer risk for BRCA1/2 mutation carriers including special populations of carriers such as pregnant or lactating patients and men. Breast cancer screening, including clinical breast examination, mammogram, and breast MRI, is important for detecting breast cancer at an early and likely curable stage. In addition to screening, counseling on risk‐reducing surgeries is strongly recommended for BRCA1/2 carriers. Risk‐reducing mastectomy decreases the risk of breast cancer development, and risk‐reducing salpingo‐oophorectomy decreases ovarian cancer‐specific as well as overall mortality, but controversy exists regarding its impact on breast cancer‐specific mortality. Given the effectiveness of screening for breast cancer, further management should be carried out on an individual basis taking into account quality of life and psychosocial factors, and recommendations should be readdressed periodically as science progresses and patients’ goals may change.     

Parent of origin differences in psychosocial burden and approach to BRCA risk management

We conducted a mixed‐method study to examine coping response in BRCA+ women based on parent of origin (maternally vs paternally inherited BRCA mutation). Quantitative findings (n = 408) revealed paternally inherited cases had genetic testing later and were more likely to have a cancer diagnosis. Having a maternally inherited mutation was the strongest predictor of proactive risk management response. Qualitative interviews (n = 56) identified proactive responses among maternally inherited cases compared to reactive responses in paternally inherited cases. Findings underscore the importance of unbiased pedigree analysis to determine cancer risk. Women with paternally inherited BRCA mutations may benefit from additional psychosocial support.     

BRCA mutation genetic testing implications in the United States

BRCA mutation carriers have a very high risk of breast and ovarian cancer by age 70, in the ranges 47%–66% and 40%–57%, respectively. Additionally, women with BRCA mutation-associated breast cancer also have an elevated risk of other or secondary malignancies. Fortunately, the breast and ovarian cancer outcome for BRCA1/2 mutation carriers is at least as good as for non-carriers with chemoprevention, prophylactic surgeries and appropriate use of therapies. Therefore, identification of those who might have a mutation is important so that genetic counseling, testing, screening and prevention strategies can be applied in a timely manner. This article reviews the impact of genetic testing in general, timing of genetic testing after diagnosis and prior knowledge of mutation status in BRCA carriers with newly diagnosed breast cancer. Additionally, risk-reducing surgeries including the prophylactic contralateral mastectomy, and bilateral salpingo-oophorectomy and the sensitivity of BRCA-defective breast cancer cell lines to differential chemotherapeutic agents will be discussed.     

Assessing the Knowledge and Attitudes Regarding Genetic Testing for Breast Cancer Risk in our Region of Southeastern Georgia

Abstract: Genetic testing for the breast cancer susceptibility genes, BRCA1 and BRCA2, has been available for over a decade. Positive test results carry significant medical, psychological, and social implications. Knowledge of the public’s awareness concerning BRCA testing, and perceived benefits and barriers to testing can help refine educational programs and identify subgroups needing additional support. Patients and their acquaintances with a breast complaint attending a surgical clinic or private office were asked to complete a questionnaire about their knowledge of breast cancer genes and their desire to be tested. Demographic information collected included ethnicity, education background, age, income, and personal and family history of breast cancer, knowledge of BRCA genes and testing, and their willingness to participate in genetic counseling. A total of 222 people completed the questionnaire that showed the majority of subjects in southeast Georgia believe breast cancer is inherited 26–50% of the time. Caucasians and those with advanced degrees are the most informed regarding awareness of BRCA genes (p < 0.05); the least informed groups include African Americans and those with no more than a college education. Participants with a family history of breast cancer were significantly more likely to know that genes had been identified that indicate an increased risk of breast cancer (p < 0.05). A history of breast cancer did not impact the degree of awareness (p > 0.05). Subjects aware of genetic testing are more willing to utilize counseling (p < 0.05). Perceptions of breast cancer inheritance, awareness of susceptibility genes, and availability of testing and counseling are not uniform among all population subgroups. In southeast Georgia, educational efforts should focus on the less educated and minority groups.     

Investigating the relationship between BRCA1 and BRCA2 genes methylation profile and sperm DNA fragmentation in infertile men

The purpose of the study was to investigate whether the promoter methylation status of BRCA1 and BRCA2 DNA repair genes is associated with sperm DNA fragmentation (sDF) in infertile men with oligoasthenoteratozoospermia (OAT) which emerges due to various reasons and is effective in male infertility. Seventy‐three infertile men with OAT and 20 normozoospermic volunteers participated in the study. To investigate sDF and methylation patterns of BRCA1 and BRCA2 gene promoters, TUNEL assay and methylation‐specific PCR (MS‐PCR) were used. The mean sDF ratio for the patients was calculated as 22.50%. The calculated cut‐off value for sDF ratio was 17.0% in ROC curve analysis. Regarding sDF, a significant difference between the normozoospermic group and the OAT group with abnormal semen parameters (p < 0.001) was found. sDF demonstrated a significant effect on the semen parameters and negative correlations on sDF ratios and sperm motility, concentration and morphology. There was no statistically significant association between sDF and the methylation status of the promoter of either BRCA1 or BRCA2 genes. In routine clinical practice, sperm DNA integrity should be investigated before applying assisted reproductive techniques. To understand better the relationship between epigenetic regulation of DNA repair genes and male infertility, additional studies are required.     

Post-mastectomy surveillance of BRCA1/BRCA2 mutation carriers: Outcomes from a specialized clinic for high-risk breast cancer patients

Female BRCA1/BRCA2 mutation carriers may elect bilateral risk-reducing mastectomy. There is a paucity of data on yield of imaging surveillance after risk-reducing mastectomy. This retrospective study focused on female BRCA1/BRCA2 mutation carriers who underwent bilateral mastectomy either as primary preventative, or as secondary preventative, after breast cancer diagnosis. All participants underwent breast imaging at 6- to 12-month intervals after mastectomy. Data on subsequent breast cancer diagnosis and timing were collected and compared between the groups. Overall, 184 female mutation carriers (134 BRCA1, 45 BRCA2, 5 both BRCA genes) underwent bilateral mastectomy after initial breast cancer diagnosis, between April 1, 2009 and August 31, 2018. During a mean follow-up of 6.2 ± 4.2 years, 13 (7.06%) were diagnosed with breast cancer; 12 ipsilateral (range: 0.4–28.8 years) and 1 contralateral breast cancer, 15.9 years after surgery. On the contrary, among asymptomatic BRCA1 (n = 40) and BRCA2 (n = 13) mutation carriers who underwent primary risk-reducing mastectomy (mean age at surgery 39.5 ± 8.4 years); none has developed breast cancer after a mean follow-up of 5.4 ± 3.4 years. BRCA1/BRCA2 mutation carriers with prior disease who underwent risk-reducing mastectomy after breast cancer diagnosis are still prone for developing ipsi or contralateral breast cancer, and therefore may benefit from continues clinical and imaging surveillance, unlike BRCA1/BRCA2 mutation carriers who undergo primary preventative bilateral mastectomy.