Accuracy of self-reported family history of cancer, mutation status and tumor characteristics in patients with early onset breast cancer

Proactive familial cancer risk assessment: a service development study in UK primary care

BACKGROUND

Family history assessment can identify individuals above population-risk for cancer to enable targeted Screening, Prevention, and Early Detection (SPED). Family History Questionnaire Service (FHQS) is a resource-efficient patient-facing online tool to facilitate this. In the UK, cancer risk assessment is usually only offered to concerned individuals proactively self-presenting to their GP, leading to inequity in accessing SPED in the community.

AIM

To improve access to community cancer genetic risk assessment and explore barriers to uptake.

DESIGN & SETTING

Service development project of a digital pathway using the FHQS for cancer risk assessment across four general practices within the clinical remit of the South West Thames Centre for Genomics (SWTCG).

METHOD

3100 individuals aged 38-50 years were invited to complete the FHQS through either text message or email. A random selection of 100 non-responders were contacted to determine barriers to uptake.

RESULTS

In total, n = 304/3100 (10%) registered for the FHQS. Responders were more likely to be British (63% vs 47%, P<0.001), speak English as their main language (92% vs 76%, P<0.001), and not require an interpreter (99.6% vs 94.9%, P = 0.001). Of 304 responders, 158 (52%) were automatically identified as at population-risk without full family history review. Of the remaining 146 responders, 52 (36%) required either additional screening referral (n = 23), genetics referral (n = 15), and/or advice to relatives (n = 18). Of 100 non-responders contacted, eight had incorrect contact details and 53 were contactable. Reasons for not responding included not receiving invitation details (n = 26), losing the invitation (n = 5), or forgetting (n = 4).

CONCLUSION

The FHQS can be used as part of a low-resource primary care pathway to identify individuals in the community above population-risk for cancer requiring action. This study highlighted barriers to uptake requiring consideration to maximise impact and minimise inequity.

Breast cancer risk assessment and risk distribution in 3,491 Slovenian women invited for screening at the age of 50; a population-based cross-sectional study

BACKGROUND

The evidence shows that risk-based strategy could be implemented to avoid unnecessary harm in mammography screening for breast cancer (BC) using age-only criterium. Our study aimed at identifying the uptake of Slovenian women to the BC risk assessment invitation and assessing the number of screening mammographies in case of risk-based screening.

PATIENTS AND METHODS

A cross-sectional population-based study enrolled 11,898 women at the age of 50, invited to BC screening. The data on BC risk factors, including breast density from the first 3,491 study responders was collected and BC risk was assessed using the Tyrer-Cuzick algorithm (version 8) to classify women into risk groups (low, population, moderately increased, and high risk group). The number of screening mammographies according to risk stratification was simulated.

RESULTS

57% (6,785) of women returned BC risk questionnaires. When stratifying 3,491 women into risk groups, 34.0% were assessed with low, 62.2% with population, 3.4% with moderately increased, and 0.4% with high 10-year BC risk. In the case of potential personalised screening, the number of screening mammographies would drop by 38.6% compared to the current screening policy.

CONCLUSIONS

The study uptake showed the feasibility of risk assessment when inviting women to regular BC screening. 3.8% of Slovenian women were recognised with higher than population 10-year BC risk. According to Slovenian BC guidelines they may be screened more often. Overall, personalised screening would decrease the number of screening mammographies in Slovenia. This information is to be considered when planning the pilot and assessing the feasibility of implementing population risk-based screening.

Host, reproductive, and lifestyle factors in relation to quantitative histologic metrics of the normal breast

BACKGROUND

Emerging data indicate that variations in quantitative epithelial and stromal tissue composition and their relative abundance in benign breast biopsies independently impact risk of future invasive breast cancer. To gain further insights into breast cancer etiopathogenesis, we investigated associations between epidemiological factors and quantitative tissue composition metrics of the normal breast.

METHODS

The study participants were 4108 healthy women ages 18-75 years who voluntarily donated breast tissue to the US-based Susan G. Komen Tissue Bank (KTB; 2008-2019). Using high-accuracy machine learning algorithms, we quantified the percentage of epithelial, stromal, adipose, and fibroglandular tissue, as well as the proportion of fibroglandular tissue that is epithelium relative to stroma (i.e., epithelium-to-stroma proportion, ESP) on digitized hematoxylin and eosin (H&E)-stained normal breast biopsy specimens. Data on epidemiological factors were obtained from participants using a detailed questionnaire administered at the time of tissue donation. Associations between epidemiological factors and square root transformed tissue metrics were investigated using multivariable linear regression models.

RESULTS

With increasing age, the amount of stromal, epithelial, and fibroglandular tissue declined and adipose tissue increased, while that of ESP demonstrated a bimodal pattern. Several epidemiological factors were associated with individual tissue composition metrics, impacting ESP as a result. Compared with premenopausal women, postmenopausal women had lower ESP [β (95% Confidence Interval (CI)) = -0.28 (- 0.43, - 0.13); P < 0.001] with ESP peaks at 30-40 years and 60-70 years among pre- and postmenopausal women, respectively. Pregnancy [β (95%CI) vs nulligravid = 0.19 (0.08, 0.30); P < 0.001] and increasing number of live births (P-trend < 0.001) were positively associated with ESP, while breastfeeding was inversely associated with ESP [β (95%CI) vs no breastfeeding = -0.15 (- 0.29, - 0.01); P = 0.036]. A positive family history of breast cancer (FHBC) [β (95%CI) vs no FHBC = 0.14 (0.02-0.26); P = 0.02], being overweight or obese [β (95%CI) vs normal weight = 0.18 (0.06-0.30); P = 0.004 and 0.32 (0.21-0.44); P < 0.001, respectively], and Black race [β (95%CI) vs White = 0.12 (- 0.005, 0.25); P = 0.06] were positively associated with ESP.

CONCLUSION

Our findings revealed that cumulative exposure to etiological factors over the lifespan impacts normal breast tissue composition metrics, individually or jointly, to alter their dynamic equilibrium, with potential implications for breast cancer susceptibility and tumor etiologic heterogeneity.

Half of germline pathogenic and likely pathogenic variants found on panel tests do not fulfil NHS testing criteria

Genetic testing for cancer predisposition has been curtailed by the cost of sequencing, and testing has been restricted by eligibility criteria. As the cost of sequencing decreases, the question of expanding multi-gene cancer panels to a broader population arises. We evaluated how many additional actionable genetic variants are returned by unrestricted panel testing in the private sector compared to those which would be returned by adhering to current NHS eligibility criteria. We reviewed 152 patients referred for multi-gene cancer panels in the private sector between 2014 and 2016. Genetic counselling and disclosure of all results was standard of care provided by the Consultant. Every panel conducted was compared to current eligibility criteria. A germline pathogenic / likely pathogenic variant (P/LP), in a gene relevant to the personal or family history of cancer, was detected in 15 patients (detection rate of 10%). 46.7% of those found to have the P/LP variants (7 of 15), or 4.6% of the entire set (7 of 152), did not fulfil NHS eligibility criteria. 46.7% of P/LP variants in this study would have been missed by national testing guidelines, all of which were actionable. However, patients who do not fulfil eligibility criteria have a higher Variant of Uncertain Significance (VUS) burden. We demonstrated that the current England NHS threshold for genetic testing is missing pathogenic variants which would alter management in 4.6%, nearly 1 in 20 individuals. However, the clinical service burden that would ensue is a detection of VUS of 34%.

Predicting cancer risk based on family history

A new software package provides more accurate cancer risk prediction profiles and has the ability to integrate more genes and cancer types in the future.

Genetic testing in women with early-onset breast cancer: a Traceback pilot study

Purpose

In Sweden, a Traceback approach, i.e., a retrospective genetic outreach activity, among cancer patients is not normally used in clinical practice. In this pilot study, we wanted to evaluate a Traceback strategy for possible future clinical implementation and investigate why not all women with early-onset breast cancer underwent genetic testing when they were first diagnosed.

Methods

Out of all women (n = 409) diagnosed with breast cancer at ≤ 35 years in Southern Sweden between 2000 and 2017, 63 had not previously been tested. These women were offered an analysis of the genes BRCA1, BRCA2, PALB2, CHEK2, and ATM through a standardized letter. Subsequently, women with normal test results were informed through a letter and carriers of pathogenic variants were contacted through a telephone call and offered in-person genetic counseling. All tested women were asked to complete a follow-up questionnaire regarding previously not having attended genetic counseling and testing and their experiences of the current retrospective approach.

Results

Out of the invited women, 29 (46%) underwent genetic testing and 27 (43%) answered the questionnaire. Pathogenic variants were identified in BRCA1 (n = 2), CHEK2 (n = 1), and ATM (n = 1). The main reason for previously not having undergone genetic testing was not having received any information from their physicians. Most study participants were satisfied with both written pre- and post-test information.

Conclusion

The process with retrospective identification, written pre-test information, and genetic testing, followed by in-person counseling for carriers of pathogenic variants only, was well accepted. This has implications for future Traceback implementation programs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06351-z.

Implementation and implications for polygenic risk scores in healthcare

Increasing amounts of genetic data have led to the development of polygenic risk scores (PRSs) for a variety of diseases. These scores, built from the summary statistics of genome-wide association studies (GWASs), are able to stratify individuals based on their genetic risk of developing various common diseases and could potentially be used to optimize the use of screening and preventative treatments and improve personalized care for patients. Many challenges are yet to be overcome, including PRS validation, healthcare professional and patient education, and healthcare systems integration. Ethical challenges are also present in how this information is used and the current lack of diverse populations with PRSs available. In this review, we discuss the topics above and cover the nature of PRSs, visualization schemes, and how PRSs can be improved. With these tools on the horizon for multiple diseases, scientists, clinicians, health systems, regulatory bodies, and the public should discuss the uses, benefits, and potential risks of PRSs.

Identification of women at risk for hereditary breast and ovarian cancer in a sample of 1000 Slovenian women: a comparison of guidelines

Background

An important number of breast and ovarian cancer cases is due to a strong genetic predisposition. The main tool for identifying individuals at risk is recognizing a suggestive family history of cancer. We present a prospective study on applying three selected clinical guidelines to a cohort of 1000 Slovenian women to determine the prevalence of at-risk women according to each of the guidelines and analyze the differences amongst the guidelines.

Methods

Personal and family history of cancer was collected for 1000 Slovenian women. Guidelines by three organizations: National Comprehensive Cancer Network (NCCN), American College of Medical Genetics in cooperation with National Society of Genetic Counselors (ACMG/NSGC), and Society of Gynecologic Oncology (SGO) were applied to the cohort. The number of women identified, the characteristics of the high-risk population, and the agreement between the guidelines were explored.

Results

NCCN guidelines identify 13.2% of women, ACMG/NSGC guidelines identify 7.1% of women, and SGO guidelines identify 7.0% of women from the Slovenian population, while 6.2% of women are identified by all three guidelines as having high-risk for hereditary breast and ovarian cancer.

Conclusions

We identified 13.7% of women from the Slovenian population as being at an increased risk for breast and ovarian cancer based on their personal and family history of cancer using all of the guidelines. There are important differences between the guidelines. NCCN guidelines are the most inclusive, identifying nearly twice the amount of women as high-risk for hereditary breast and ovarian cancer as compared to the AGMG/NSCG and SGO guidelines in the Slovenian population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08400-8.

Mainstreamed genetic testing of breast cancer patients in two hospitals in South Eastern Norway

Studies have shown that a significant number of eligible breast cancer patients are not offered genetic testing or referral to genetic counseling. To increase access to genetic testing in South Eastern Norway, testing has since 2014 been offered directly to breast cancer patients by surgeons and oncologists. This practice is termed “mainstreamed genetic testing”. The aim of this study was to investigate to what extent patients in South Eastern Norway are offered testing. Three hundred and sixty one patients diagnosed in 2016 and 2017 at one regional and one university hospital in South Eastern Norway were included. Data on whether the patients fulfilled the criteria, whether they had been offered testing and if they were tested were collected. In total, 26.6% (96/361) fulfilled the criteria for testing. Seventy five percent (69/92) of these were offered testing, and 71.7% (66/92) were tested. At the university hospital, 90.2% (37/41) of eligible patients were offered testing, and at the regional hospital 62.7% (32/51). Fifty two percent (12/23) of eligible patient not offered testing were younger than 50 years at time of diagnosis. As many as 95.4% (125/131) of all patients who were offered testing, wanted to be tested. The majority of patients who fulfilled the criteria were offered testing, supporting the practice of mainstreamed genetic testing. There were nevertheless differences in rates of testing between the hospitals that affected all groups of patients, indicating that genetic testing may not be equally accessible to all patients. We suggest that efforts should be made to increase awareness and improve routines for genetic testing of breast cancer patients in Norway.

Variations in the Referral Pattern for Genetic Counseling of Patients with Early-Onset Breast Cancer: A Population-Based Study in Southern Sweden

Swedish national breast cancer guidelines recommend that all women diagnosed with breast cancer (BC) at the age of 35 years or younger should be referred to their regional oncogenetic clinic for genetic counseling and testing, regardless of family history of cancer. The main objective of this study was to evaluate whether place of residence at BC diagnosis and treating hospital were associated with the fact that not all BC patients diagnosed at ≤35 years in the southern part of Sweden have attended genetic counseling and testing. Between 2000 and 2013, 279 women in the South Swedish Health Care Region were diagnosed with BC at ≤35 years. Information regarding place of residence at BC diagnosis, treating hospital, time of registration and first meeting at the Oncogenetic Clinic in Lund, and genetic testing was collected. With a follow-up period until August 2018, 64% were registered at the clinic (60% underwent genetic testing) and 36% were not. BC patients from 2 counties and from rural settings with a population of <10,000 inhabitants were significantly less likely to be registered at the clinic. Our results suggest that place of residence at BC diagnosis and treating hospital were associated with the probability of referral for genetic counseling and testing for women diagnosed with BC at ≤35 years in the South Swedish Health Care Region. We propose, as a generalizable finding, that further educational and outreach activities within the health care system and the community may be needed to ensure that all women diagnosed with early-onset BC receive proper genetic counseling.

MICA-129 Met/Val polymorphism could be a genetic biomarker for Familial Breast Cancer in the Tunisian population

Identification of candidate genes associated with susceptibility of breast cancer can have a significant impact at a cancer management national healthcare systems level, making genetic testing more affordable and cost-effective. We have previously shown that the major histocompatibility complex class I-related chain A (MICA) was related to breast cancer and plays an important role in modulating immune response mechanisms through NKG2D receptor activation. Compared to our previous study, in this work, we recruited a new cohort composed of 354 unrelated Tunisian women affected by breast cancer and 380 age-matched women as controls, all genotyped for MICA-129 Met/Val (rs 1051792). Subsequently, we exanimated the distribution of this polymorphism in ten families. As a result, an association was found between the Val allele and Val/Val genotype and the risk of breast cancer (p = 2.5 × 10^-15 ; OR = 2.40; p = 6.5 × 10^-13 ; OR = 3.03, respectively). Stratified analysis with age and family history of cancer revealed an association between the Val/Val genotype and younger patients <40 years (p = .003; OR = 2.03). Among those patients having a family history of cancer, 68% had a Val/Val genotype (p = .02; OR = 1.82). In the family study, an analyse of pedigrees revealed that the majority of families showed the development of breast cancer at a young age. Moreover, all patients diagnosed with early-onset breast cancer had a Val/Val genotype. Our results lead us to propose that this polymorphism may be an inherited genetic biomarker contributing to an increased breast cancer risk in Tunisian women.

Race/Ethnicity and Accuracy of Self-Reported Female First-Degree Family History of Breast and Other Cancers in the Northern California Breast Cancer Family Registry

BACKGROUND

Few studies have evaluated accuracy of self-reported family history of breast and other cancers in racial/ethnic minorities.

METHODS

We assessed the accuracy of cancer family history reports by women with breast cancer (probands) from the Northern California Breast Cancer Family Registry compared with 2 reference standards: personal cancer history reports by female first-degree relatives and California Cancer Registry records.

RESULTS

Probands reported breast cancer in first-degree relatives with high accuracy, but accuracy was lower for other cancers. Sensitivity (percentage correctly identifying relatives with cancer) was 93% [95% confidence interval (CI), 89.5-95.4] when compared with the relatives' self-report of breast cancer as the reference standard and varied little by proband race/ethnicity and other demographic factors, except for marginally lower sensitivity for Hispanic white probands (87.3%; 95% CI, 78.0-93.1; P = 0.07) than non-Hispanic white probands (95.1%; 95% CI, 88.9-98.0). Accuracy was also high when compared with cancer registry records as the reference standard, with a sensitivity of 95.5% (95% CI, 93.4-96.9) for breast cancer, but lower sensitivity for Hispanic white probands (91.2%; 95% CI, 84.4-95.2; P = 0.05) and probands with low English language proficiency (80%; 95% CI, 52.8-93.5; P < 0.01).

CONCLUSIONS

Non-Hispanic white, African American, and Asian American probands reported first-degree breast cancer family history with high accuracy, although sensitivity was lower for Hispanic white probands and those with low English language proficiency.

IMPACT

Self-reported family history of breast cancer in first-degree relatives is highly accurate and can be used as a reliable standard when other validation methods are not available.

Familial occurrence of mitral regurgitation in patients with mitral valve prolapse undergoing mitral valve surgery

Background

Initial studies have suggested the familial clustering of mitral valve prolapse, but most of them were either community based among unselected individuals or applied non-specific diagnostic criteria. Therefore little is known about the familial distribution of mitral regurgitation in a referral-type population with a more severe mitral valve prolapse phenotype. The objective of this study was to evaluate the presence of familial mitral regurgitation in patients undergoing surgery for mitral valve prolapse, differentiating patients with Barlow's disease, Barlow forme fruste and fibro-elastic deficiency.

Methods

A total of 385 patients (62 ± 12 years, 63% men) who underwent surgery for mitral valve prolapse were contacted to assess cardiac family history systematically. Only the documented presence of mitral regurgitation was considered to define ‘familial mitral regurgitation’. In the probands, the aetiology of mitral valve prolapse was defined by surgical observations.

Results

A total of 107 (28%) probands were classified as having Barlow's disease, 85 (22%) as Barlow forme fruste and 193 (50%) patients as fibro-elastic deficiency. In total, 51 patients (13%) reported a clear family history for mitral regurgitation; these patients were significantly younger, more often diagnosed with Barlow's disease and also reported more sudden death in their family as compared with ‘sporadic mitral regurgitation’. In particular, ‘familial mitral regurgitation’ was reported in 28 patients with Barlow's disease (26%), 15 patients (8%) with fibro-elastic deficiency and eight (9%) with Barlow forme fruste (P < 0.001).

Conclusions

In a large cohort of patients operated for mitral valve prolapse, the self-reported prevalence of familial mitral regurgitation was 26% in patients with Barlow's disease and still 8% in patients with fibro-elastic deficiency, highlighting the importance of familial anamnesis and echocardiographic screening in all mitral valve prolapse patients.

Electronically ascertained extended pedigrees in breast cancer genetic counseling

A comprehensive pedigree, usually provided by the counselee and verified by medical records, is essential for risk assessment in cancer genetic counseling. Collecting the relevant information is time-consuming and sometimes impossible. We studied the use of electronically ascertained pedigrees (EGP). The study group comprised women (n = 1352) receiving HBOC genetic counseling between December 2006 and December 2016 at Landspitali in Iceland. EGP's were ascertained using information from the population-based Genealogy Database and Icelandic Cancer Registry. The likelihood of being positive for the Icelandic founder BRCA2 pathogenic variant NM_000059.3:c.767_771delCAAAT was calculated using the risk assessment program Boadicea. We used this unique data to estimate the optimal size of pedigrees, e.g., those that best balance the accuracy of risk assessment using Boadicea and cost of ascertainment. Sub-groups of randomly selected 104 positive and 105 negative women for the founder BRCA2 PV were formed and Receiver Operating Characteristics curves compared for efficiency of PV prediction with a Boadicea score. The optimal pedigree size included 3° relatives or up to five generations with an average no. of 53.8 individuals (range 9-220) (AUC 0.801). Adding 4° relatives did not improve the outcome. Pedigrees including 3° relatives are difficult and sometimes impossible to generate with conventional methods. Pedigrees ascertained with data from pre-existing genealogy databases and cancer registries can save effort and contain more information than traditional pedigrees. Genetic services should consider generating EGP's which requires access to an accurate genealogy database and cancer registry. Local data protection laws and regulations have to be addressed.

Incidence of Pathogenic Variants in Those With a Family History of Pancreatic Cancer

Discovery of a hereditary cancer syndrome can be one of the factors that determine whether a healthy individual completes pancreas cancer screening or whether an individual with cancer receives certain chemotherapies. Retrospective review was completed to determine the likelihood of detection of a pathogenic variant causing a hereditary cancer syndrome based on personal and family history. Study was completed through the hereditary cancer clinic at Mayo Clinic Florida over a 6 year period, 1/2012 through 1/2018. All participants were referred based on suspicion for a hereditary cancer syndrome based on personal and/or family history. Patients' personal oncologic history at time of consultation was recorded, as well as, cancer diagnoses in the family history and the number of family members with a history of pancreas cancer. Test result and gene name, if variant was pathogenic or likely pathogenic, were noted as well. A total of 2,019 patients completed genetic testing during study period. Personal history of cancer included a variety of primaries, including breast (N = 986), ovarian (N = 119), colon (N = 106), prostate (N = 65), and pancreas (N = 59). A positive result was discovered in 11% of the total group. Two hundred and eighty five reported a family history of pancreas cancer. The incidence of pathogenic variants was 13% (37/285) in those with any family history and 23% (13/56) in those with two or more relatives with pancreatic cancer. Those with multiple relatives with pancreatic cancer were significantly more likely to carry a pathogenic variant than those with a personal history of breast cancer under the age of 45 (23.2 vs. 11.9%, p = 0.02). Presence of multiple family members with a reported history of pancreatic cancer significantly increased the likelihood that a pathogenic variant would be identified in the patient even over other significant risk factors, like personal history of early onset breast cancer.

Risk-reducing bilateral salpingo-oophorectomy in women with BRCA1 or BRCA2 mutations

BACKGROUND

The presence of deleterious mutations in breast cancer 1 gene (BRCA1) or breast cancer 2 gene (BRCA2) significantly increases the risk of developing some cancers, such as breast and high-grade serous cancer (HGSC) of ovarian, tubal and peritoneal origin. Risk-reducing salpingo-oophorectomy (RRSO) is usually recommended to BRCA1 or BRCA2 carriers after completion of childbearing. Despite prior systematic reviews and meta-analyses on the role of RRSO in reducing the mortality and incidence of breast, HGSC and other cancers, RRSO is still an area of debate and it is unclear whether RRSO differs in effectiveness by type of mutation carried.

OBJECTIVES

To assess the benefits and harms of RRSO in women with BRCA1 or BRCA2 mutations.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 7) in The Cochrane Library, MEDLINE Ovid, Embase Ovid and trial registries, with no language restrictions up to July 2017. We handsearched abstracts of scientific meetings and other relevant publications.

SELECTION CRITERIA

We included non-randomised trials (NRS), prospective and retrospective cohort studies, and case series that used statistical adjustment for baseline case mix using multivariable analyses comparing RRSO versus no RRSO in women without a previous or coexisting breast, ovarian or fallopian tube malignancy, in women with or without hysterectomy, and in women with a risk-reducing mastectomy (RRM) before, with or after RRSO.

DATA COLLECTION AND ANALYSIS

We extracted data and performed meta-analyses of hazard ratios (HR) for time-to-event variables and risk ratios (RR) for dichotomous outcomes, with 95% confidence intervals (CI). To assess bias in the studies, we used the ROBINS-I 'Risk of bias' assessment tool. We quantified inconsistency between studies by estimating the I² statistic. We used random-effects models to calculate pooled effect estimates.

MAIN RESULTS

We included 10 cohort studies, comprising 8087 participants (2936 (36%) surgical participants and 5151 (64%) control participants who were BRCA1 or BRCA2 mutation carriers. All the studies compared RRSO with or without RRM versus no RRSO (surveillance). The certainty of evidence by GRADE assessment was very low due to serious risk of bias. Nine studies, including 7927 women, were included in the meta-analyses. The median follow-up period ranged from 0.5 to 27.4 years.

MAIN OUTCOMES

overall survival was longer with RRSO compared with no RRSO (HR 0.32, 95% CI 0.19 to 0.54; P < 0.001; 3 studies, 2548 women; very low-certainty evidence). HGSC cancer mortality (HR 0.06, 95% CI 0.02 to 0.17; I² = 69%; P < 0.0001; 3 studies, 2534 women; very low-certainty evidence) and breast cancer mortality (HR 0.58, 95% CI 0.39 to 0.88; I² = 65%; P = 0.009; 7 studies, 7198 women; very low-certainty evidence) were lower with RRSO compared with no RRSO. None of the studies reported bone fracture incidence. There was a difference in favour of RRSO compared with no RRSO in terms of ovarian cancer risk perception quality of life (MD 15.40, 95% CI 8.76 to 22.04; P < 0.00001; 1 study; very low-certainty evidence). None of the studies reported adverse events.Subgroup analyses for main outcomes: meta-analysis showed an increase in overall survival among women who had RRSO versus women without RRSO who were BRCA1 mutation carriers (HR 0.30, 95% CI 0.17 to 0.52; P < 0001; I² = 23%; 3 studies; very low-certainty evidence) and BRCA2 mutation carriers (HR 0.44, 95% CI 0.23 to 0.85; P = 0.01; I² = 0%; 2 studies; very low-certainty evidence). The meta-analysis showed a decrease in HGSC cancer mortality among women with RRSO versus no RRSO who were BRCA1 mutation carriers (HR 0.10, 95% CI 0.02 to 0.41; I² = 54%; P = 0.001; 2 studies; very low-certainty evidence), but uncertain for BRCA2 mutation carriers due to low frequency of HGSC cancer deaths in BRCA2 mutation carriers. There was a decrease in breast cancer mortality among women with RRSO versus no RRSO who were BRCA1 mutation carriers (HR 0.45, 95% CI 0.30 to 0.67; I² = 0%; P < 0.0001; 4 studies; very low-certainty evidence), but not for BRCA2 mutation carriers (HR 0.88, 95% CI 0.42 to 1.87; I² = 63%; P = 0.75; 3 studies; very low-certainty evidence). One study showed a difference in favour of RRSO versus no RRSO in improving quality of life for ovarian cancer risk perception in women who were BRCA1 mutation carriers (MD 10.70, 95% CI 2.45 to 18.95; P = 0.01; 98 women; very low-certainty evidence) and BRCA2 mutation carriers (MD 13.00, 95% CI 3.59 to 22.41; P = 0.007; very low-certainty evidence). Data from one study showed a difference in favour of RRSO and RRM versus no RRSO in increasing overall survival (HR 0.14, 95% CI 0.02 to 0.98; P = 0.0001; I² = 0%; low-certainty evidence), but no difference for breast cancer mortality (HR 0.78, 95% CI 0.51 to 1.19; P = 0.25; very low-certainty evidence). The risk estimates for breast cancer mortality according to age at RRSO (50 years of age or less versus more than 50 years) was not protective and did not differ for BRCA1 (HR 0.85, 95% CI 0.64 to 1.11; I² = 16%; P = 0.23; very low-certainty evidence) and BRCA2 carriers (HR 0.88, 95% CI 0.42 to 1.87; I² = 63%; P = 0.75; very low-certainty evidence).

AUTHORS' CONCLUSIONS

There is very low-certainty evidence that RRSO may increase overall survival and lower HGSC and breast cancer mortality for BRCA1 and BRCA2 carriers. Very low-certainty evidence suggests that RRSO reduces the risk of death from HGSC and breast cancer in women with BRCA1 mutations. Evidence for the effect of RRSO on HGSC and breast cancer in BRCA2 carriers was very uncertain due to low numbers. These results should be interpreted with caution due to questionable study designs, risk of bias profiles, and very low-certainty evidence. We cannot draw any conclusions regarding bone fracture incidence, quality of life, or severe adverse events for RRSO, or for effects of RRSO based on type and age at risk-reducing surgery. Further research on these outcomes is warranted to explore differential effects for BRCA1 or BRCA2 mutations.