Prophylactic mastectomy versus surveillance for the prevention of breast cancer in women's BRCA carriers

Prevention, diagnosis and clinical management of hereditary breast cancer beyond BRCA1/2 genes

The detection of germline pathogenic variants (gPVs) in BRCA1/2 and other breast cancer (BC) genes is rising exponentially thanks to the advent of multi-gene panel testing. This promising technology, coupled with the availability of specific therapies for BC BRCA-related, has increased the number of patients eligible for genetic testing. Implementing multi-gene panel testing for hereditary BC screening holds promise to maximise benefits for patients at hereditary risk of BC. These benefits range from prevention programs to antineoplastic-targeted therapies. However, the clinical management of these patients is complex and requires guidelines based on recent evidence. Furthermore, applying multi-gene panel testing into clinical practice increases the detection of variants of uncertain significance (VUSs). This augments the complexity of patients' clinical management, becoming an unmet need for medical oncologists. This review aims to collect updated evidence on the most common BC-related genes besides BRCA1/2, from their biological role in BC development to their potential impact in tailoring prevention and treatment strategies.

Cancer genetic counselling for hereditary breast cancer in the era of precision oncology

A relevant percentage of breast cancers (BCs) are tied to pathogenetic (P)/likely pathogenetic (LP) variants in predisposing genes. The knowledge of P/LP variants is an essential element in the management of BC patients since the first diagnosis because it influences surgery and subsequent oncological treatments and follow-up. Moreover, patients with metastatic BCs can benefit from personalized treatment if carriers of P/LP in BRCA1/2 genes. Multigene panels allow the identification of other predisposing genes with an impact on management. Cascade genetic testing for healthy family members allows personalized preventive strategies. Here, we review the advances and the challenges of Cancer Genetic Counseling (CGC). We focus on the area of oncology directed to hereditary BC management describing the peculiar way to lead CGC and how CGC changes over time. The authors describe the impact of genetic testing by targeted approach or universal approach on the management of BC according to the stage at diagnosis. Moreover, they describe the burden of CGC and testing and future perspectives to widely offer testing. A new perspective is needed for models of service delivery of CGC and testing, beyond formal genetic counselling. A broader genetic test can be quickly usable in clinical practice for comprehensive BC management and personalized prevention in the era of precision oncology.

Role of Breast Cancer Risk Estimation Models to Identify Women Eligible for Genetic Testing and Risk-Reducing Surgery

Hereditary breast and ovarian cancer (HBOC) syndrome is responsible for approximately 10% of breast cancers (BCs). The HBOC gene panel includes both high-risk genes, i.e., a four times higher risk of BC (BRCA1, BRCA2, PALB2, CDH1, PTEN, STK11 and TP53), and moderate-risk genes, i.e., a two to four times higher risk of BC (BARD1, CHEK2, RAD51C, RAD51D and ATM). Pathogenic germline variants (PGVs) in HBOC genes confer an absolute risk of BC that changes according to the gene considered. We illustrate and compare different BC risk estimation models, also describing their limitations. These models allow us to identify women eligible for genetic testing and possibly to offer surgical strategies for primary prevention, i.e., risk-reducing mastectomies and salpingo-oophorectomies.

Difficulties of gender affirming treatment in trans women with BRCA1+ mutation: A case report

Gender affirming treatment in transgender women is based on a combination of antiandrogens and estrogens, with the latter maintained over the long term. When prescribing these treatments, we must consider the possibility of developing estrogen-dependent breast cancer. In transgender women, a breast cancer incidence of 4.1 per 100,000 has been estimated, which would increase the risk by 46% in relation to cisgender men but decrease it by 70% in relation to cisgender women. It is known that certain gene mutations such as BRCA1 imply an increased risk of breast cancer, but at present the risk in transgender women with BRCA1 treated with estrogens is not well established. We present the case of a transgender woman with a family history of breast cancer and BRCA1 mutation and the therapeutic decisions made in a multidisciplinary team. Following this case, we review and discuss the published literature.

Reclassifying BRCA1 c.4358-2A > G and BRCA2 c.475 + 5G > C variants from "Uncertain Significance" to "Pathogenic" based on minigene assays and clinical evidence

BACKGROUND

Pathogenic variants in BRCA genes play a crucial role in the pathogenesis of ovarian cancer. Intronic variants of uncertain significance (VUS) may contribute to pathogenicity by affecting splicing. Currently, the significance of many intronic variants in BRCA has not been clarified, impacting patient treatment strategies and the management of familial cases.

METHOD

A retrospective study was conducted to analyze BRCA intronic VUS in a cohort of 707 unrelated ovarian cancer patients at a single institution from 2018 to 2023. Three splicing predictors were employed to analyze detected intronic VUS. Variants predicted to have splicing alterations were selected for further validation through minigene assays. Patient and familial investigations were conducted to comprehend cancer incidence within pedigrees and the application of poly (ADP-ribose) polymerase inhibitors (PARPi) by the patients. In accordance with the guidelines of the American College of Medical Genetics and Genomics (ACMG), the intronic VUS were reclassified based on minigene assay results and clinical evidence.

RESULT

Approximately 9.8% (69/707) of patients were identified as carriers of 67 different VUS in BRCA1/2, with four intronic variants accounting for 6% (4/67) of all VUS. Splicing predictors indicated potential splicing alterations in splicing for BRCA1 c.4358-2A>G and BRCA2 c.475+5G>C variants. Minigene assays utilizing the pSPL3 exon trapping vector revealed that these variants induced changes in splicing sites and frameshift, resulting in premature termination of translation (p. Ala1453Glyfs and p. Pro143Glyfs). According to ACMG guidelines, BRCA1 c.4358-2A>G and BRCA2 c.475+5G>C were reclassified as pathogenic variants. Pedigree investigations were conducted on patients with BRCA1 c.4358-2A>G variant, and the detailed utilization of PARPi provided valuable insights into research on PARPi resistance.

CONCLUSION

Two intronic VUS were reclassified as pathogenic variants. A precise classification of variants is crucial for the effective treatment and management of both patients and healthy carriers.

Impact of non-BRCA genes in the indication of risk-reducing surgery in hereditary breast and ovarian cancer syndrome (HBOC)

Hereditary breast and ovarian cancer syndrome (HBOC) is associated with other genes beyond BRCA. The performance of prophylactic bilateral mastectomy (PBM) and risk-reducing salpingo-oophorectomy (RRSO) are primary prevention measures that can be recommended depending on the type of pathogenic/likely pathogenic (P/LP) variant detected or family history. Descriptive, retrospective, and observational audit. Between the years 2015 to May 2023, a total of 288 families were studied by a multigene panel using NGS. Statistical analysis was performed using IBM SPSS Statistics 22. Non-BRCA P/LP variants were detected in 38 families (84.2% females and 15.8% males); 18 in ATM (44.7 %), 7 in CHEK2 (18.4%), 5 in TP53 (13.2%), 2 in PTEN (5.3%), 2 in PALB2 (5.3%), 1 in RAD51C (2.6%), 1 in BRIP1 (2.6%), 1 in CDH1 (2.6%) and 1 in RAD51D (2.6%). Risk-reducing surgery was recommended in 18 patients (PBM in 18 [46.2 %] and RRSO in 5 [13.2%]). Given the results of our study, we support the recommendations of the guidelines on the use of multigene panels in the study of HBOC. Knowing P/LP variants beyond BRCA1 and 2 has an impact on the follow-up and primary and secondary prevention of affected families.

Diagnosis, Management, and Surveillance for Patients With PALB2, CHEK2, and ATM Gene Mutations

BACKGROUND

This study aims to capture clinical and surgical practice patterns of patients with deleterious mutations in partner and localizer of BRCA2 (PALB2), checkpoint kinase 2 (CHEK2) and ataxia telangiesctasia mutated (ATM) genes.

MATERIALS AND METHODS

This study is a retrospective chart review of patients with PALB2, CHEK2 or ATM mutations. Patient demographics, testing indications, management decisions, and surveillance strategies were recorded.

RESULTS

Sixty-two patients were found to have deleterious mutations: 14 (23%) with a PALB2 mutation, 30 (48%) with a CHEK2 mutation, and 18 (29%) patients with an ATM mutation. Thirty-one (50%) patients have a history of breast cancer. Twenty-three patients were diagnosed and treated prior to genetic testing while 8 patients learned of their mutation status and breast cancer diagnosis simultaneously. Of these 8 patients, 4 sought treatment at our institution, 3 underwent bilateral mastectomy, and 1 patient opted for lumpectomy and surveillance. Thirty-one patients had no history of breast cancer. After genetic diagnosis, 3 of the 9 patients who continued clinical follow-up proceeded with bilateral prophylactic mastectomy within 2 years. Clinical surveillance continued for 23 months on average.

CONCLUSION

Most patients who learned of their genetic and breast cancer diagnoses simultaneously underwent bilateral mastectomy, whereas only a third of patients without cancer opted for bilateral prophylactic mastectomy.

From the patient to the population: Use of genomics for population screening

Genomic medicine is expanding from a focus on diagnosis at the patient level to prevention at the population level given the ongoing under-ascertainment of high-risk and actionable genetic conditions using current strategies, particularly hereditary breast and ovarian cancer (HBOC), Lynch Syndrome (LS) and familial hypercholesterolemia (FH). The availability of large-scale next-generation sequencing strategies and preventive options for these conditions makes it increasingly feasible to screen pre-symptomatic individuals through public health-based approaches, rather than restricting testing to high-risk groups. This raises anew, and with urgency, questions about the limits of screening as well as the moral authority and capacity to screen for genetic conditions at a population level. We aimed to answer some of these critical questions by using the WHO Wilson and Jungner criteria to guide a synthesis of current evidence on population genomic screening for HBOC, LS, and FH.

Controversies and Open Questions in Management of Cancer-Free Carriers of Germline Pathogenic Variants in BRCA1/BRCA2

Females harboring germline BRCA1/BRCA2 (BRCA) P/LPV are offered a tight surveillance scheme from the age of 25−30 years, aimed at early detection of specific cancer types, in addition to risk-reducing strategies. Multiple national and international surveillance guidelines have been published and updated over the last two decades from geographically diverse countries. We searched for guidelines published between 1 January 2015 and 1 May 2022. Differences between guidelines on issues such as primary prevention, mammography screening in young (<30 years) carriers, MRI screening in carriers above age 65 years, breast imaging (if any) after risk-reducing bilateral mastectomy, during pregnancy, and breastfeeding, and hormone-replacement therapy, are just a few notable examples. Beyond formal guidelines, BRCA carriers’ concerns also focus on the timing of risk-reducing surgeries, fertility preservation, management of menopausal symptoms in cancer survivors, and pancreatic cancer surveillance, issues that, for some, there are no data to support evidence-based recommendations. This review discusses these unsettled issues, emphasizing the importance of future studies to enable global guideline harmonization for optimal surveillance strategies. Moreover, it raises the unmet need for personalized risk stratification and surveillance in BRCA P/LPV carriers.

Risk‐reducing mastectomy decisions among women with mutations in high‐ and moderate‐ penetrance breast cancer susceptibility genes

Background

Women harboring mutations in breast cancer susceptibility genes are at increased lifetime risk of developing breast cancer and are faced with decisions about risk management, including whether to undergo high‐risk screening or risk‐reducing mastectomy (RRM). National guidelines recommend BRCA1 or BRCA2 mutation carriers consider RRM, but that carriers of moderate penetrance mutations (e.g., ATM or CHEK2) should be managed based on family history. We aimed to investigate determinants of decision for RRM, and hypothesized that mutation status, age, family history, partner status, and breast cancer would impact RRM decision making.

Methods

We performed a retrospective study assessing RRM decisions for 279 women.

Results

Women with BRCA and moderate penetrance gene mutations, a personal history of breast cancer, or a first degree relative with a history of breast cancer were more likely to undergo RRM. Breast cancer status and age showed an interaction effect such that women with breast cancer were less likely to undergo RRM with increasing age.

Conclusion

Although national guidelines do not recommend RRM for moderate penetrance carriers, the rates of RRM for this population approached those for BRCA mutation carriers. Further insights are needed to better support RRM decision‐making in this population.

BRCA1 and Breast Cancer: Molecular Mechanisms and Therapeutic Strategies

Breast cancer susceptibility gene 1 (BRCA1) is a tumor suppressor gene, which is mainly involved in the repair of DNA damage, cell cycle regulation, maintenance of genome stability, and other important physiological processes. Mutations or defects in the BRCA1 gene significantly increase the risk of breast, ovarian, prostate, and other cancers in carriers. In this review, we summarized the molecular functions and regulation of BRCA1 and discussed recent insights into the detection and treatment of BRCA1 mutated breast cancer.

Breast cancer risk reduction: who, why, and what?

Women at increased risk of breast cancer have options to mitigate that risk. Understanding factors that increase risk and utilizing tools for quantitative estimates are important to be able to adequately counsel and target strategies for patients. On the basis of these estimates, patients may be able to engage in risk reduction interventions and increased screening, including chemoprevention or surgical risk reduction. Multiple organizations have published guidelines supporting risk assessment, genetic assessment, increased screening, and prevention measures for these women.

Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic focus primarily on assessment of pathogenic or likely pathogenic variants associated with increased risk of breast, ovarian, and pancreatic cancer and recommended approaches to genetic testing/counseling and management strategies in individuals with these pathogenic or likely pathogenic variants. This manuscript focuses on cancer risk and risk management for BRCA-related breast/ovarian cancer syndrome and Li-Fraumeni syndrome. Carriers of a BRCA1/2 pathogenic or likely pathogenic variant have an excessive risk for both breast and ovarian cancer that warrants consideration of more intensive screening and preventive strategies. There is also evidence that risks of prostate cancer and pancreatic cancer are elevated in these carriers. Li-Fraumeni syndrome is a highly penetrant cancer syndrome associated with a high lifetime risk for cancer, including soft tissue sarcomas, osteosarcomas, premenopausal breast cancer, colon cancer, gastric cancer, adrenocortical carcinoma, and brain tumors.