Age at first birth and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers

Neoadjuvant Chemotherapy Response and Genetic Susceptibility in Recently Parous Women with Breast Cancer: A Retrospective Analysis

BACKGROUND

Women with recent parity are at increased short-term breast cancer (BC) risk and face a worse prognosis. The effect of parity on response to neoadjuvant chemotherapy (NAC) is unstudied, and the influence of inherited susceptibility on parity-related short-term risk remains unclear.

METHODS

A retrospective case-cohort study analyzed women age 50 years or younger with non-metastatic BC diagnosed between 2010 and 2020 who underwent genetic testing and were treated at Northwestern Medicine. Associations between NAC response and recency of parity were evaluated using multivariate logistic regression, stratified by tumor biologic subtypes. Relationships between germline mutations, recency of parity, and BC were explored via multi-state modeling and linear regression.

RESULTS

Among 1080 eligible women, 231 received NAC. Treatment response was poorer in parous women with triple-negative tumors than in nullipara women regardless of the recency of parity (P < 0.03). Among 122 women (11.3%) with detectable pathogenic mutations, adjusted analyses with both modeling approaches showed no indications that BRCA1/2 carriers had a greater hazard of a BC diagnosis in the decade after recent parity than nulliparous mutation carriers. For BRCA2 and PALB2 carriers, BC diagnosis occurred less frequently in the postpartum intervals.

CONCLUSION

This study showed a poor response to NAC in parous triple-negative BC (TNBC) patients than in nullipara patients. The effects of immunotherapy-based regimens deserve evaluation in the context of parity. Postpartum BC occurrence is not increased in BRCA1/2 carriers. The effects of rarer susceptibility genes may differ. These important effects of parity on BC in young women and those at genetic risk warrant larger prospective studies.

Neoadjuvant chemotherapy response and genetic susceptibility in recently parous women with breast cancer

Introduction

Women with recent parity are at increased short-term breast cancer (BC) risk and face a worse prognosis. The effect of parity on response to neoadjuvant chemotherapy (NAC) is unstudied, and the influence of inherited susceptibility on parity-related short-term risk remains unclear.

Methods

We conducted a retrospective case-cohort study among women aged ≤50 with non-metastatic BC diagnosed between 2010 and 2020 who underwent genetic testing and were treated at Northwestern Medicine. Associations between NAC response and recency of parity were evaluated using multivariate logistic regression, stratified by tumor biologic subtypes. Relationships between germline mutations, recency of parity, and BC were explored via multi-state modeling and linear regression.

Results

Among 1,080 eligible women, 231 received NAC. Treatment response was poorer in parous women with triple negative tumors compared to nullipara, regardless of the recency of parity ( P <0.03). Among 122 women (11.3%) with detectable pathogenic mutations, adjusted analyses with both modeling approaches revealed no indications that BRCA1/2 carriers had an increased hazard of BC diagnosis in the decade following recent parity, compared to nulliparous mutation carriers. For BRCA2 and PALB2 carriers, breast cancer diagnosis occurred less frequently in the post-partum intervals.

Conclusion

We observed a poor response to NAC in parous TNBC patients compared to nullipara; effects of immunotherapy-based regimens deserve evaluation in the context of parity. Post-partum BC occurrence is not increased in BRCA1/2 carriers; effects of rarer susceptibility genes may differ. These important effects of parity on BC in young women and those at genetic risk warrant larger prospective studies.

BRCA Mutations and Breast Cancer Prevention

Women who inherit a deleterious BRCA1 or BRCA2 mutation face substantially increased risks of developing breast cancer, which is estimated at 70%. Although annual screening with magnetic resonance imaging (MRI) and mammography promotes the earlier detection of the disease, the gold standard for the primary prevention of breast cancer remains bilateral mastectomy. In the current paper, I review the evidence regarding the management of healthy BRCA mutation carriers, including key risk factors and protective factors, and also discuss potential chemoprevention options. I also provide an overview of the key findings from the literature published to date, with a focus on data from studies that are well-powered, and preferably prospective in nature.

Reducing the Risk of Gynecologic Cancer in Hereditary Breast Ovarian Cancer Syndrome Mutation Carriers: Moral Dilemmas and the Principle of Double Effect

Hereditary breast ovarian cancer (HBOC) syndrome is an autosomal dominant disease linked to mutations in the BRCA1 and BRCA2 genes in 90 percent of affected families. Female mutation carriers are highly susceptible to aggressive, often disseminated, usually fatal pelvic-abdominal carcinomatosis. This cancer risk can be markedly reduced by surgical removal of the internal gynecologic organs before the end of the fourth decade of life and by using estrogen-progestin formulations marketed for many years as combined oral contraceptives (COCs). Both risk-reducing methods are associated with unfavorable effects. Relying on the principle of double effect, this essay argues for the ethical justification of prophylactic surgery and the use of COC to reduce the risk of gynecologic cancer in HBOC syndrome mutation carriers. Summary: Hereditary breast ovarian cancer syndrome is an autosomal dominant disease linked to mutations in the BRCA1 and BRCA2 genes in most affected families. Female mutation carriers are highly susceptible to aggressive, often disseminated, usually fatal pelvic-abdominal carcinomatosis. This cancer risk can be markedly reduced by surgical removal of the internal gynecologic organs before the end of the fourth decade of life and by using estrogen-progestin formulations marketed for many years as combined oral contraceptives. Both risk-reducing methods are associated with unfavorable effects. Relying on the principle of double effect, this essay argues for the ethical justification for those unfavorable effects.

Age at first full-term birth and breast cancer risk in BRCA1 and BRCA2 mutation carriers

PURPOSE

In the general population, an early age at first full-term birth confers protection against the risk of developing breast cancer. The relationship between age at first birth and breast cancer risk is not clear for women with a mutation in the BRCA1 or BRCA2 gene. Thus, we undertook a case-control study of women with a BRCA1 or BRCA2 mutation to study the effects of age at first full-term birth matched for other reproductive factors.

METHODS

Information about reproductive factors, including age at first birth as well as medical history, was collected from a routinely administered research questionnaire. There were 2,295 matched pairs of women with a BRCA1 or BRCA2 mutation included in the final analysis.

RESULTS

There was no significant difference in the mean age at first full-term birth among the BRCA1 (24.9 vs. 25.2; P = 0.10) or BRCA2 mutation carriers (26.5 vs. 26.6 years; P = 0.80). Findings were similar in the analysis limited to cases who were diagnosed with breast cancer prior to age 45.

CONCLUSION

This matched analysis of a large number of BRCA mutation carriers suggests that age at first birth has little influence on BRCA1 or BRCA2 breast cancer risk.

Stellate cells and mesenchymal stem cells in benign mammary stroma are associated with risk factors for breast cancer - an observational study

Background

It is not known whether stromal cells in benign breast tissue can mediate risk of breast cancer. We recently described aldehyde dehydrogenase 1 A1 (ALDH1) positive (+) cells in morphologically normal breast stroma of premenopausal women, and the data indicated that their distribution is associated with clinical risk factors for breast cancer. The aim of the present study was to define the identities of these cells using histologic and immunohistologic methods, and to investigate associations between those cells and hormonal and genetic risk factors in pre- and postmenopausal women.

Methods

Stroma of morphologically normal tissue was analyzed in samples from 101 well-characterized women whose breasts had been operated. Morphology and immunolabeling were applied to determine cell identities based on the putative stem cell markers ALDH1 and stage-specific embryonic antigen-3 (SSEA3), and immunophenotypes indicating mast cells or stellate cells. The results were compared with the patients’ risk factors using regression analysis (two-tailed).

Results

ALDH1+ round/oval cells were associated with low parity in BRCA1/2 carriers (p = 0.022), while in non-BRCA1/2-carriers they were negatively associated with nulliparity (p = 0.057). In premenopausal women ALDH1+ round/oval cells were associated with family history (p = 0.058). SSEA3+ round/oval cells were morphologically and immunohistologically consistent with multilineage stress-enduring (Muse) cells, and these cells were independently associated with the breast cancer risk factors low parity (p = 0.015), family history (p = 0.021), and hormone use after menopause (p = 0.032). ALDH1+ spindle-shaped/polygonal cells were immunohistologically consistent with stellate cells, and were negatively associated with family history of breast cancer (p = 0.001).

Conclusion

This study identified novel stromal cell types in benign breast tissue that have a potential for stratifying women for breast cancer risk.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4151-x) contains supplementary material, which is available to authorized users.

Young age at first pregnancy does protect against early onset breast cancer in BRCA1 and BRCA2 mutation carriers

Purpose

Previous research assessing the impact of pregnancy and age at first pregnancy on breast cancer risk in BRCA1 and BRCA2 mutation carriers has produced conflicting results, with some studies showing an increased risk following early first pregnancy in contrast to the reduced risk in the general population of women. The present study addresses these inconsistencies.

Methods

Female BRCA1 and BRCA2 carriers from North West England were assessed for breast cancer incidence prior to 50 years of age comparing those with an early first full-term pregnancy (< 21 years) to those without a full-term pregnancy. Breast cancer incidence per decade from 20 years and Kaplan–Meier analyses were performed.

Results

2424 female mutation carriers (1278 BRCA1; 1146 BRCA2) developed 990 breast cancers under the age of 50 years. Women who had their first term pregnancy prior to age 21 (n = 441) had a lower cancer incidence especially between age 30–39 years. Kaplan–Meier analysis showed an odds ratio of 0.78 for BRCA1 (p = 0.005) and 0.73 for BRCA2 (p = 0.002).

Conclusions

The present study demonstrates a clear protective effect of early first pregnancy on breast cancer risk in both BRCA1 and BRCA2 mutation carriers.

Reproductive factors as risk modifiers of breast cancer in BRCA mutation carriers and high-risk non-carriers

This study was conducted to identify the role of reproductive factors as environmental modifiers for breast cancer (BC) risk in clinic-based, East-Asian BRCA1 and BRCA2 mutation carriers and non-carriers with high-risk criteria of BRCA mutations (family history (FH) of BC, early-onset BC (aged ≤40 years)). A total of 581 women who were BRCA carriers (222 BRCA1 and 359 BRCA2), 1,083 non-carriers with FH, and 886 non-carriers with early-onset BC were enrolled and interviewed to examine the reproductive factors, from 2007 to 2014. The hazard ratio (HR) and its 95% confidence interval (CI) in the weighted Cox regression model were used to calculate the BC risk based on the reproductive factors. Earlier menarche increased BC risk by 3.49-fold in BRCA2 mutation carriers (95%CI=2.03-6.00) and 3.30-fold in non-carriers with FH (95%CI=1.73-6.34), but was insignificantly associated with BRCA1 carriers and non-carriers for early-onset BC (P-heterogeneity=0.047). Higher parity decreased BC risk in BRCA carriers and non-carriers with FH, especially in BRCA1 carriers (HR=0.27, 95% CI=0.09-0.83 for two parity; and HR=0.23, 95%CI=0.05-1.00 for ≥3 parity), but increased the early-onset BC risk (HR=4.63, 95%CI=2.56-8.51 for >3 parity, p-heterogeneity=0.045). Oral contraceptive (OC) use and longer estrogen exposure periods (≥30 years) were associated with an increased risk of early-onset BC (HR=3.99, 95%CI=1.65-9.67; HR=7.69, 95%CI=1.96-25.01), while OC use was not associated with BC risk in other groups and longer estrogen exposure had rather decreased risk for BC risk (both p-heterogeneity<0.001). Several reproductive factors as risk modifiers could heterogeneously be associated with BC among BRCA1/2 mutation carriers, non-carriers with FH, and early-onset BC non-carriers.

Bioinformatic analysis of computational identified differentially expressed genes in tumor stoma of pregnancy‑associated breast cancer

The present study aimed to screen the differentially expressed genes (DEGs) in tumor‑associated stroma of pregnancy‑associated breast cancer (PABC). By analyzing Affymetrix microarray data (GSE31192) from the Gene Expression Omnibus database, DEGs between tumor asso-ciated stromal cells and normal stromal cells in PABC were identified. Gene Ontology (GO) function and pathway enrichment analyses for the DEGs were then performed, followed by construction of a protein‑protein interaction (PPI) network. A total of 94 upregulated and 386 downregulated DEGs were identified between tumor associated stromal cells and normal stromal cells in patients with PABC. The upregulated DEGs were primarily enriched in the cytokine‑cytokine receptor interaction pathway and GO terms associated with the immune response, which included the DEGs of interleukin 18 (IL18) and cluster of differentiation 274 (CD274). The downregulated DEGs were primarily involved in GO terms associated with cell surface receptor linked signal transduction and pathways of focal adhesion and pathways in cancer. In the PPI network, nodes of jun proto‑oncogene (JUN), FBJ murine osteosarcoma viral oncogene homolog (FOS), V‑myc avian myelocytomatosis viral oncogene homolog (MYC), and alpha‑smooth muscle actin (ACTA2) had higher degrees. The hub genes of JUN, FOS, MYC and ACTA2, as well as the DEGs IL18 and CD274 that were associated with the immune response in GO terms may exert important functions in the molecular mechanisms of PABC. These genes may be used as new molecular targets in the treatment of this disease.

MEN1-Dependent Breast Cancer: Indication for Early Screening? Results From the Dutch MEN1 Study Group

OBJECTIVE

Multiple endocrine neoplasia type 1 (MEN1) is associated with an early-onset elevated breast cancer risk. This finding potentially has implications for breast cancer screening for women with MEN1, and therefore it is necessary to assess whether other risk factors are involved to identify those at greatest risk.

DESIGN

A cross-sectional case control study was performed using the Dutch MEN1 cohort, including >90% of the adult Dutch MEN1 population. All women with a confirmed MEN1 mutation received a questionnaire regarding cancer family history and breast cancer-related endocrine and general cancer risk factors.

RESULTS

A total of 138 of 165 (84%) eligible women with MEN1 completed the questionnaire. Eleven of the 138 women had breast cancer. Another 34 relatives with breast cancer were identified in the families of the included women, of whom 11 were obligate MEN1 carriers, 14 had no MEN1 mutation, and 9 had an unknown MEN1 status. The median age at breast cancer diagnosis of women with MEN1 (n = 22) was 45 years (range, 30 to 80 years), in comparison with 57.5 years (range, 40 to 85 years) in female relatives without MEN1 (n = 14; P = 0.03) and 61.2 years in the Dutch reference population. Known endocrine risk factors and general risk factors were not different for women with and without breast cancer.

CONCLUSION

The increased breast cancer risk in MEN1 carriers was not related to other known breast cancer risk factors or familial cancer history, and therefore breast cancer surveillance from the age of 40 years for all women with MEN1 is justifiable.

[Breast and ovarian cancer due to BRCA1&2 hereditary cancer predisposition syndrome and reproduction: literature review]

INTRODUCTION

Germline mutations BRCA1&2 are responsible in women for breast and ovarian cancers that commonly occur at a young age: as such, there are strong interactions between the oncological risks and the events of reproductive life, pregnancy, breastfeeding, and management of infertility.

MATERIALS AND METHODS

A review of the international literature from the PubMed database was conducted, and recommendations of French health agencies were exposed. Published studies are case-control and cohort studies in the majority, with a low level of evidence.

RESULTS

Pregnancy and lactation have no effect on breast and ovaries or even decreases the risk. The sex ratio among patients carrying the mutation is in favor of girls. It is not observed more infertility in patients carrying a mutation despite a strong suspicion of premature ovarian failure, and infertility treatments do not increase breast and ovarian risk. There are ethical debates concerning the place of pre-natal diagnosis: both experts and concerned patients recommend a case-by-case analysis of the requests.

Timing of oral contraceptive use and the risk of breast cancer in BRCA1 mutation carriers

It is not clear if early oral contraceptive use increases the risk of breast cancer among young women with a breast cancer susceptibility gene 1 (BRCA1) mutation. Given the benefit of oral contraceptives for the prevention of ovarian cancer, estimating age-specific risk ratios for oral contraceptive use and breast cancer is important. We conducted a case-control study of 2,492 matched pairs of women with a deleterious BRCA1 mutation. Breast cancer cases and unaffected controls were matched on year of birth and country of residence. Detailed information about oral contraceptive use was collected from a routinely administered questionnaire. Conditional logistic regression was used to estimate the odds ratios (OR) and 95 % confidence intervals (CI) for the association between oral contraceptive and breast cancer, by age at first use and by age at diagnosis. Among BRCA1 mutation carriers, oral contraceptive use was significantly associated with an increased risk of breast cancer for women who started the pill prior to age 20 (OR 1.45; 95 % CI 1.20-1.75; P = 0.0001) and possibly between ages 20 and 25 as well (OR 1.19; 95 % CI 0.99-1.42; P = 0.06). The effect was limited to breast cancers diagnosed before age 40 (OR 1.40; 95 % CI 1.14-1.70; P = 0.001); the risk of early-onset breast cancer increased by 11 % with each additional year of pill use when initiated prior to age 20 (OR 1.11; 95 % CI 1.03-1.20; P = 0.008). There was no observed increase for women diagnosed at or after the age of 40 (OR 0.97; 95 % CI 0.79-1.20; P = 0.81). Oral contraceptive use before age 25 increases the risk of early-onset breast cancer among women with a BRCA1 mutation and the risk increases with duration of use. Caution should be taken when advising women with a BRCA1 mutation to take an oral contraceptive prior to age 25.

Reproductive factors and breast cancer risk among BRCA1 or BRCA2 mutation carriers: results from ten studies

Although reproductive factors are among the most well-established risk factors for breast cancer in the general population, it is still a matter for debate whether these factors act as risk modifiers among BRCA1 or BRCA2 mutation carriers. This meta-analysis is the first to be performed to determine the relationship between reproductive factors and breast cancer risk among BRCA1 and BRCA2 mutation carriers. We searched the PubMed database up to February 2013. A total of ten studies met the inclusion criteria. The results showed that the reproductive factors may be associated with breast cancer risk only among BRCA1 mutation carriers. No association was found between parity and breast cancer risk. Compared with women at the youngest age in the first-birth category, women in the oldest age category were at a 38% lower risk of breast cancer (RR=0.62, 95%CI=0.45-0.85). Breastfeeding for at least 1 or 2 years was associated with a 37% reduction in breast cancer risk (RR=0.63, 95%CI=0.46-0.86). Women at the oldest age in the menarche category were at a 34% lower risk of breast cancer (RR=0.66, 95%CI=0.53-0.81) than women in the youngest age category. However, none of the reproductive factors were associated with breast cancer risk among BRCA2 mutation carriers. In conclusion, late age at first birth, breastfeeding, and late age at menarche protect against breast cancer in BRCA1 mutation carriers only. Further studies are needed to explore the mechanisms.

Variation in breast cancer risk associated with factors related to pregnancies according to truncating mutation location, in the French National BRCA1 and BRCA2 mutations carrier cohort (GENEPSO)

INTRODUCTION

Mutations in BRCA1 and BRCA2 confer a high risk of breast cancer (BC), but the magnitude of this risk seems to vary according to the study and various factors. Although controversial, there are data to support the hypothesis of allelic risk heterogeneity.

METHODS

We assessed variation in BC risk according to factors related to pregnancies by location of mutation in the homogeneous risk region of BRCA1 and BRCA2 in 990 women in the French study GENEPSO by using a weighted Cox regression model.

RESULTS

Our results confirm the existence of the protective effect of an increasing number of full-term pregnancies (FTPs) toward BC among BRCA1 and BRCA2 mutation carriers (≥3 versus 0 FTPs: hazard ratio (HR) = 0.51, 95% confidence interval (CI) = 0.33 to 0.81). Additionally, the HR shows an association between incomplete pregnancies and a higher BC risk, which reached 2.39 (95% CI = 1.28 to 4.45) among women who had at least three incomplete pregnancies when compared with women with zero incomplete pregnancies. This increased risk appeared to be restricted to incomplete pregnancies occurring before the first FTP (HR = 1.77, 95% CI = 1.19 to 2.63). We defined the TMAP score (defined as the Time of Breast Mitotic Activity during Pregnancies) to take into account simultaneously the opposite effect of full-term and interrupted pregnancies. Compared with women with a TMAP score of less than 0.35, an increasing TMAP score was associated with a statistically significant increase in the risk of BC (P trend = 0.02) which reached 1.97 (95% CI = 1.19 to 3.29) for a TMAP score >0.5 (versus TMAP ≤0.35). All these results appeared to be similar in BRCA1 and BRCA2. Nevertheless, our results suggest a variation in BC risk associated with parity according to the location of the mutation in BRCA1. Indeed, parity seems to be associated with a significantly decreased risk of BC only among women with a mutation in the central region of BRCA1 (low-risk region) (≥1 versus 0 FTP: HR = 0.27, 95% CI = 0.13 to 0.55) (Pinteraction <10-3).

CONCLUSIONS

Our findings show that, taking into account environmental and lifestyle modifiers, mutation position might be important for the clinical management of BRCA1 and BRCA2 mutation carriers and could also be helpful in understanding how BRCA1 and BRCA2 genes are involved in BC.

Oophorectomy after menopause and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers

BACKGROUND

To evaluate the effect of the cumulative number of ovulatory cycles and its contributing components on the risk of breast cancer among BRCA mutation carriers.

METHODS

We conducted a matched case-control study on 2,854 pairs of women with a BRCA1 or BRCA2 mutation. Conditional logistic regression was used to estimate the association between the number of ovulatory cycles and various exposures and the risk of breast cancer. Information from a subset of these women enrolled in a prospective cohort study was used to calculate age-specific breast cancer rates.

RESULTS

The annual risk of breast cancer decreased with the number of ovulatory cycles experienced (ρ = -0.69; P = 0.03). Age at menarche and duration of breastfeeding were inversely related with risk of breast cancer among BRCA1 (P(trend) < 0.0001) but not among BRCA2 (P(trend) ≥ 0.28) mutation carriers. The reduction in breast cancer risk associated with surgical menopause [OR, 0.52; 95% confidence interval (CI), 0.40-0.66; P(trend) < 0.0001] was greater than that associated with natural menopause (OR, 0.81; 95% CI, 0.62-1.07; P(trend) = 0.14). There was a highly significant reduction in breast cancer risk among women who had an oophorectomy after natural menopause (OR, 0.13; 95% CI, 0.02-0.54; P = 0.006).

CONCLUSIONS

These data challenge the hypothesis that breast cancer risk can be predicted by the lifetime number of ovulatory cycles in women with a BRCA mutation. Both pre- and postmenopausal oophorectomy protect against breast cancer.

IMPACT

Understanding the basis for the protective effect of oophorectomy has important implications for chemoprevention.

Breast cancer and pregnancy: current concepts in diagnosis and treatment

The treatment of breast cancer diagnosed during pregnancy presents a challenging situation for the patient, family, and caregivers. Case series have demonstrated the efficacy and safety of using anthracycline-based chemotherapy during the second and third trimesters. Additionally, patients should be seen, evaluated, and treated in a multidisciplinary setting with facilitated communication among the medical oncologist, surgical oncologist, obstetrician, radiation oncologist, pathologist, and radiologist. This review details the available data regarding the diagnosis and management of the pregnant breast cancer patient.

Evaluation of established breast cancer risk factors as modifiers of BRCA1 or BRCA2: a multi-center case-only analysis

The incomplete penetrance of mutations in BRCA1 and BRCA2 suggests that some combination of environmental and genetic factors modifies the risk of breast cancer in mutation carriers. This study sought to identify possible interactions between established breast cancer risk factors and BRCA1 or BRCA2 mutations using a case-only study design. Breast cancer cases that had been tested for BRCA1 and BRCA2 mutations were identified from 11 collaborating centers. Comparisons of reproductive and lifestyle risk factors were made between women with breast cancer who were positive for BRCA1 mutations (n = 283), BRCA2 mutations (n = 204), or negative for both BRCA1 and BRCA2 mutations (n = 894). Interaction risk ratios (IRRs) were calculated using multinominal logistic regression models. Compared with non-carriers, statistically significant IRRs were observed for later age at menarche among BRCA2 mutation carriers, for a greater number of pregnancies among both BRCA1 and BRCA2 mutation carriers, and for alcohol use among BRCA1 mutation carriers. Our data suggest that the risk for breast cancer among BRCA1 or BRCA2 carriers may be modified by reproductive characteristics and alcohol use. However, our results should be interpreted cautiously given the overall inconsistency in the epidemiologic literature on modifiers of BRCA1 and BRCA2.

Reproductive factors and risk of contralateral breast cancer by BRCA1 and BRCA2 mutation status: results from the WECARE study

OBJECTIVE

Reproductive factors, such as early age at menarche, late age at menopause, and nulliparity are known risk factors for breast cancer. Previously, we reported these factors to be associated with risk of developing contralateral breast cancer (CBC). In this study, we evaluated the association between these factors and CBC risk among BRCA1 and BRCA2 (BRCA1/2) mutation carriers and non-carriers.

METHODS

The WECARE Study is a population-based multi-center case-control study of 705 women with CBC (cases) and 1,397 women with unilateral breast cancer (controls). All participants were screened for BRCA1/2 mutations and 181 carriers were identified. Conditional logistic regression models were used to evaluate associations between reproductive factors and CBC for mutation carriers and non-carriers.

RESULTS

None of the associations between reproductive factors and CBC risk differed between mutation carriers and non-carriers. The increase in risk with younger age at menarche and decrease in risk in women with more than two full-term pregnancies seen in non-carriers were not significantly different in carriers (adjusted RRs = 1.31, 95% CI 0.65-2.65 and 0.53, 95% CI 0.19-1.51, respectively). No significant associations between the other reproductive factors and CBC risk were observed in mutation carriers or non-carriers.

CONCLUSION

For two reproductive factors previously shown to be associated with CBC risk, we observed similar associations for BRCA1/2 carriers. This suggests that reproductive variables that affect CBC risk may have similar effects in mutation carriers and non-carriers.

The breast cancer and the environment research centers: transdisciplinary research on the role of the environment in breast cancer etiology

OBJECTIVES

We introduce and describe the Breast Cancer and the Environment Research Centers (BCERC), a research network with a transdisciplinary approach to elucidating the role of environmental factors in pubertal development as a window on breast cancer etiology. We describe the organization of four national centers integrated into the BCERC network.

DATA SOURCES

Investigators use a common conceptual framework based on multiple levels of biologic, behavioral, and social organization across the life span. The approach connects basic biologic studies with rodent models and tissue culture systems, a coordinated multicenter epidemiologic cohort study of prepubertal girls, and the integration of community members of breast cancer advocates as key members of the research team to comprise the network.

DATA EXTRACTION

Relevant literature is reviewed that describes current knowledge across levels of organization. Individual research questions and hypotheses in BCERC are driven by gaps in our knowledge that are presented at genetic, metabolic, cellular, individual, and environmental (physical and social) levels.

DATA SYNTHESIS

As data collection on the cohort, animal experiments, and analyses proceed, results will be synthesized through a transdisciplinary approach.

CONCLUSION

Center investigators are addressing a large number of specific research questions related to early pubertal onset, which is an established risk factor for breast cancer. BCERC research findings aimed at the primary prevention of breast cancer will be disseminated to the scientific community and to the public by breast cancer advocates, who have been integral members of the research process from its inception.

The counseling and management of young healthy BRCA mutation carriers

Although more than 15 years have elapsed since the discovery of the BRCA1 and BRCA2 genes and the associated increased risk of breast and ovarian cancers in mutation carriers, our understanding of the syndrome is still evolving. With the accumulation of knowledge, more questions arise regarding the proper approach to mutation carriers diagnosed as having cancer. Moreover, the number of questions regarding the recommended management methods for healthy carriers and the potential risk-reducing measures is increasing constantly.In this review, we discuss these issues and summarize contemporary recommendations.

Parity and the risk of breast and ovarian cancer in BRCA1 and BRCA2 mutation carriers

Environmental or lifestyle factors are likely to explain part of the heterogeneity in breast and ovarian cancer risk among BRCA1 and BRCA2 mutation carriers. We assessed parity as a risk modifier in 515 and 503 Spanish female carriers of mutations in BRCA1 and BRCA2, respectively. Hazard ratios (HR) and their corresponding 95% confidence intervals (CI) were estimated using weighted Cox proportional hazards regression, adjusted for year of birth and study centre. The results for ever being parous and number of live-births were very similar for carriers of mutations in both genes. For all mutation carriers combined, the estimated HR associated with ever having had a live-birth was 0.74 (95% confidence interval [CI] = 0.55-1.01, P = 0.06), and that associated with each live-birth was 0.87 (95%CI = 0.77-0.98, P = 0.02). The latter association was observed only in women aged 40 and above (HR = 0.81, 95%CI = 0.70-0.94, P = 0.004 vs. HR = 0.99, 95%CI = 0.83-1.18, P = 0.9 for women under age 40), and this trend was highly consistently observed for carriers of mutations in each gene. There was no evidence of an association between breast cancer risk and age at first birth for parous BRCA1 or BRCA2 mutation carriers (P-trend >or= 0.3). The power to detect associations with ovarian cancer risk was much lower, especially for BRCA2 mutation carriers. Nevertheless, having a live-birth was associated with protection for BRCA1 mutation carriers (HR = 0.41, 95%CI = 0.18-0.94, P = 0.03), and a strong and consistent protective effect of age at first birth was observed for parous carriers of mutations in both genes (HR = 0.65, 95%CI = 0.52-0.83, P < 0.001). This is the third independent study to find that, as in the general population, parity appears to be associated with protection from breast cancer in women with mutations in BRCA1 and BRCA2. Parity appears to be protective for ovarian cancer in BRCA1 mutation carriers, but its role in BRCA2 mutation carriers remains unclear. Whether later age at first birth is also protective for ovarian cancer in mutation carriers requires further confirmation.