Menopausal hormone therapy in BRCA1 mutation carriers: uncertainty and caution

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.

Safety of hormone replacement therapy following risk-reducing salpingo-oophorectomy: systematic review of literature and guidelines

Background: Women at high risk to develop ovarian cancer opt for risk-reducing salpingo-oophorectomy (RRSO) to reduce the risk by 80-96%. RRSO leads to a direct onset of menopause in premenopausal women. Hormone replacement therapy (HRT) can be used to mitigate menopausal symptoms after RRSO. However, it is unclear whether HRT in these women is safe in terms of breast cancer (BC) risk. Methods: We performed a literature search and investigated national guidelines on the use of HRT following RRSO in BRCA1 and BRCA2 mutation carriers. We analyzed differences and similarities between the guidelines and describe what these guidelines were based upon. Results: Seven articles regarding HRT following RRSO in BRCA1 and BRCA2 mutation carriers were identified. None of the included studies yielded any evidence that short-term use of HRT following RRSO increases the risk of developing BC or negates the protective effect of RRSO in BRCA1/2 mutation carriers without a personal history of BC. Eleven national guidelines were found and described. Conclusion: Short-term use of HRT after RRSO seems to be safe. The literature is more favorable toward estrogen alone. The ideal dosage and duration of use are unknown and remain to be investigated in future studies.

Genetics of breast cancer: a topic in evolution

A hereditary predisposition to breast cancer significantly influences screening and follow-up recommendations for high-risk women. However, in patients with a suggestive personal and/or family history, a specific predisposing gene is identified in <30% of cases. Up to 25% of hereditary cases are due to a mutation in one of the few identified rare, but highly penetrant genes (BRCA1, BRCA2, PTEN, TP53, CDH1, and STK11), which confer up to an 80% lifetime risk of breast cancer. An additional 2%-3% of cases are due to a mutation in a rare, moderate-penetrance gene (e.g. CHEK2, BRIP1, ATM, and PALB2), each associated with a twofold increase in risk. Prediction models suggest that there are unlikely to be additional yet to be identified high-penetrance genes. Investigation of common, low-penetrance alleles contributing to risk in a polygenic fashion has yielded a small number of suggestive single-nucleotide polymorphisms (SNPs), but the contributive risk of an individual SNP is quite small. Mutation testing is currently recommended for individual genes in the appropriate clinical setting where there is a high index of suspicion for a specific mutated gene or syndrome. Next-generation sequencing offers a new venue for risk assessment. At the present time, there are clear clinical guidelines for individuals with a mutation in a high-penetrance gene. Otherwise, standard models are used to predict an individual's lifetime risk by clinical and family history rather than genomic information.

Evidence of gene-environment interactions between common breast cancer susceptibility loci and established environmental risk factors

Various common genetic susceptibility loci have been identified for breast cancer; however, it is unclear how they combine with lifestyle/environmental risk factors to influence risk. We undertook an international collaborative study to assess gene-environment interaction for risk of breast cancer. Data from 24 studies of the Breast Cancer Association Consortium were pooled. Using up to 34,793 invasive breast cancers and 41,099 controls, we examined whether the relative risks associated with 23 single nucleotide polymorphisms were modified by 10 established environmental risk factors (age at menarche, parity, breastfeeding, body mass index, height, oral contraceptive use, menopausal hormone therapy use, alcohol consumption, cigarette smoking, physical activity) in women of European ancestry. We used logistic regression models stratified by study and adjusted for age and performed likelihood ratio tests to assess gene-environment interactions. All statistical tests were two-sided. We replicated previously reported potential interactions between LSP1-rs3817198 and parity (Pinteraction = 2.4 × 10(-6)) and between CASP8-rs17468277 and alcohol consumption (Pinteraction = 3.1 × 10(-4)). Overall, the per-allele odds ratio (95% confidence interval) for LSP1-rs3817198 was 1.08 (1.01-1.16) in nulliparous women and ranged from 1.03 (0.96-1.10) in parous women with one birth to 1.26 (1.16-1.37) in women with at least four births. For CASP8-rs17468277, the per-allele OR was 0.91 (0.85-0.98) in those with an alcohol intake of <20 g/day and 1.45 (1.14-1.85) in those who drank ≥ 20 g/day. Additionally, interaction was found between 1p11.2-rs11249433 and ever being parous (Pinteraction = 5.3 × 10(-5)), with a per-allele OR of 1.14 (1.11-1.17) in parous women and 0.98 (0.92-1.05) in nulliparous women. These data provide first strong evidence that the risk of breast cancer associated with some common genetic variants may vary with environmental risk factors.

Risk factors associated with the occurrence of breast cancer after bilateral salpingo-oophorectomy in high-risk women

INTRODUCTION

Bilateral salpingo-oophorectomy (BSO) is a common procedure for preventing breast and ovarian cancer in high-risk women. The goal of this study was to determine the incidence of subsequent breast cancer (BC) in a high-risk population and to identify clinical and epidemiological predictors of BC following BSO.

MATERIALS AND METHODS

One hundred and thirty-three consecutive high-risk women, tested for BRCA1 and BRCA2 mutations due to family history, underwent preventive or therapeutic BSO at one of the study hospitals. One hundred and three patients had breast tissue at risk and were considered evaluable for the event-free survival analysis. Twenty-five women harbored a deleterious mutation in BRCA1 and 25 in BRCA2 genes.

RESULTS

Fifteen cases of invasive BC were diagnosed with a median interval of 49 months after BSO. Multivariate analysis showed that a prior BC after 50 years of age (p=0.004), age over 50 years at the time of BSO (p=0.005), and prior replacement or contraceptive hormonal treatment (p=0.007) were significantly associated with a shorter event-free survival.

CONCLUSION

In conclusion, age at prior diagnosis of cancer, age at BSO and prior hormonal treatment may be predictors of breast cancer after BSO.