Risk of asynchronous contralateral breast cancer in noncarriers of BRCA1 and BRCA2 mutations with a family history of breast cancer: a report from the Women's Environmental Cancer and Radiation Epidemiology Study

Case-Case Genome-Wide Analyses Identify Subtype-Informative Variants That Confer Risk for Breast Cancer

Breast cancer includes several subtypes with distinct characteristic biological, pathologic, and clinical features. Elucidating subtype-specific genetic etiology could provide insights into the heterogeneity of breast cancer to facilitate the development of improved prevention and treatment approaches. In this study, we conducted pairwise case-case comparisons among five breast cancer subtypes by applying a case-case genome-wide association study (CC-GWAS) approach to summary statistics data of the Breast Cancer Association Consortium. The approach identified 13 statistically significant loci and eight suggestive loci, the majority of which were identified from comparisons between triple-negative breast cancer (TNBC) and luminal A breast cancer. Associations of lead variants in 12 loci remained statistically significant after accounting for previously reported breast cancer susceptibility variants, among which, two were genome-wide significant. Fine mapping implicated putative functional/causal variants and risk genes at several loci, e.g., 3q26.31/TNFSF10, 8q22.3/NACAP1/GRHL2, and 8q23.3/LINC00536/TRPS1, for TNBC as compared with luminal cancer. Functional investigation further identified rs16867605 at 8q22.3 as a SNP that modulates the enhancer activity of GRHL2. Subtype-informative polygenic risk scores (PRS) were derived, and patients with a high subtype-informative PRS had an up to two-fold increased risk of being diagnosed with TNBC instead of luminal cancers. The CC-GWAS PRS remained statistically significant after adjusting for TNBC PRS derived from traditional case-control GWAS in The Cancer Genome Atlas and the African Ancestry Breast Cancer Genetic Consortium. The CC-GWAS PRS was also associated with overall survival and disease-specific survival among patients with breast cancer. Overall, these findings have advanced our understanding of the genetic etiology of breast cancer subtypes, particularly for TNBC. Significance: The discovery of subtype-informative genetic risk variants for breast cancer advances our understanding of the etiologic heterogeneity of breast cancer, which could accelerate the identification of targets and personalized strategies for prevention and treatment.

Survival analysis for patients with metachronous contralateral breast cancer: Insights from a retrospective study

Continued advances in the diagnosis and treatment of breast cancer (BC) have led to an increase in the number of long-term BC survivors and an increase in the incidence of metachronous BC in the contralateral breast. Therefore, it is important to understand the factors that influence the development of metachronous BC; however, the impact of the laterality of the initial ipsilateral (I)BC as a risk factor for the development of metachronous contralateral (MC)BC has not been extensively investigated. The present study included 17,082 female patients with stage 0-3 IBC from the prospectively maintained Korean Breast Cancer Registry from 1989-2013 and divided them into two groups: Patients with MCBC (n=88) and those without MCBC (n=16,994). Risk factors that present at the initial BC diagnosis that could significantly influence the development of MCBC were screened for and risks were evaluated using the Fine-Gray subdistribution hazard model. Significant differences in baseline characteristics between MCBC and non-MCBC groups were demonstrated. Patients aged <40 years, those with histological and nuclear grade 3 tumors, and those with the triple-negative BC subtype were significantly more prevalent in the MCBC group than in the non-MCBC group. Additionally, the cumulative incidence of MCBC increased over time, with a notable increase from 0.1% in year 1 to 1.6% in year 10. Survival analysis revealed no significant differences in overall or BC-specific survival between the two groups. Key predictive factors identified for MCBC included an age of <40 years at initial diagnosis, a negative progesterone receptor status, and a Ki-67 score of >14%. Overall, the present study revealed several factors associated with MCBC and emphasized the need for long-term monitoring of BC survivors, considering these newly identified risk factors.

Second Primary Breast Cancer in Young Breast Cancer Survivors

Importance

Among women diagnosed with primary breast cancer (BC) at or younger than age 40 years, prior data suggest that their risk of a second primary BC (SPBC) is higher than that of women who are older when they develop a first primary BC.

Objective

To estimate cumulative incidence and characterize risk factors of SPBC among young patients with BC.

Design, Setting, and Participants

Participants were enrolled in the Young Women's Breast Cancer Study, a prospective study of 1297 women aged 40 years or younger who were diagnosed with stage 0 to III BC from August 2006 to June 2015. Demographic, genetic testing, treatment, and outcome data were collected by patient surveys and medical record review. A time-to-event analysis was used to account for competing risks when determining cumulative incidence of SPBC, and Fine-Gray subdistribution hazard models were used to evaluate associations between clinical factors and SPBC risk. Data were analyzed from January to May 2023.

Main Outcomes and Measures

The 5- and 10- year cumulative incidence of SPBC.

Results

In all, 685 women with stage 0 to III BC (mean [SD] age at primary BC diagnosis, 36 [4] years) who underwent unilateral mastectomy or lumpectomy as the primary surgery for BC were included in the analysis. Over a median (IQR) follow-up of 10.0 (7.4-12.1) years, 17 patients (2.5%) developed an SPBC; 2 of these patients had cancer in the ipsilateral breast after lumpectomy. The median (IQR) time from primary BC diagnosis to SPBC was 4.2 (3.3-5.6) years. Among 577 women who underwent genetic testing, the 10-year risk of SPBC was 2.2% for women who did not carry a pathogenic variant (12 of 544) and 8.9% for carriers of a pathogenic variant (3 of 33). In multivariate analyses, the risk of SPBC was higher among PV carriers vs noncarriers (subdistribution hazard ratio [sHR], 5.27; 95% CI, 1.43-19.43) and women with primary in situ BC vs invasive BC (sHR, 5.61; 95% CI, 1.52-20.70).

Conclusions

Findings of this cohort study suggest that young BC survivors without a germline pathogenic variant have a low risk of developing a SPBC in the first 10 years after diagnosis. Findings from germline genetic testing may inform treatment decision-making and follow-up care considerations in this population.

Society of Surgical Oncology Breast Disease Site Working Group Statement on Contralateral Mastectomy: Indications, Outcomes, and Risks

Rates of contralateral mastectomy (CM) among patients with unilateral breast cancer have been increasing in the United States. In this Society of Surgical Oncology position statement, we review the literature addressing the indications, risks, and benefits of CM since the society's 2017 statement. We held a virtual meeting to outline key topics and then conducted a literature search using PubMed to identify relevant articles. We reviewed the articles and made recommendations based on group consensus. Patients consider CM for many reasons, including concerns regarding the risk of contralateral breast cancer (CBC), desire for improved cosmesis and symmetry, and preferences to avoid ongoing screening, whereas surgeons primarily consider CBC risk when making a recommendation for CM. For patients with a high risk of CBC, CM reduces the risk of new breast cancer, however it is not known to convey an overall survival benefit. Studies evaluating patient satisfaction with CM and reconstruction have yielded mixed results. Imaging with mammography within 12 months before CM is recommended, but routine preoperative breast magnetic resonance imaging is not; there is also no evidence to support routine postmastectomy imaging surveillance. Because the likelihood of identifying an occult malignancy during CM is low, routine sentinel lymph node surgery is not recommended. Data on the rates of postoperative complications are conflicting, and such complications may not be directly related to CM. Adjuvant therapy delays due to complications have not been reported. Surgeons can reduce CM rates by encouraging shared decision making and informed discussions incorporating patient preferences.

Contralateral prophylactic mastectomy in a rural population: A single-institution experience

Background

The incidence of contralateral prophylactic mastectomy (CPM) for unilateral breast cancer (UBC) has continued to increase, despite an absent survival benefit except in populations at highest risk for developing contralateral breast cancer (CBC). CPM rates may be higher in rural populations but causes remain unclear. A study performed at our institution previously found that 21.8 % of patients with UBC underwent CPM from 2000 to 2009. This study aimed to evaluate the CPM trend at a single institution serving a rural population and identify the CPM rate in average-risk patients.

Methods

Retrospective review of patients who underwent mastectomies for UBC at our institution from 2017 to 2021 was performed. Analysis utilized frequencies and percentages, descriptive statistics, chi-square, and independent sample t-tests.

Results

A total of 438 patients were included, of whom 64.4 % underwent bilateral mastectomy for UBC (CPM). Patients who underwent CPM were significantly younger, underwent genetic testing, had germline pathogenic variants, had a family history of breast cancer, had smaller tumors, underwent reconstruction, and had more wound infections. Of CPM patients, 50.4 % had no identifiable factors for increased risk of developing CBC.

Conclusions

The rate of CPM in a rural population at a single institution increased from 21.8 % to 64.4 % over two decades, with an average-risk CPM rate of 50.4 %. Those that undergo CPM are more likely to undergo reconstruction and have more wound infections. Identifying characteristics of patients undergoing CPM in a rural population and the increased associated risks allows for a better understanding of this trend to guide conversations with patients.

Key message

This study demonstrates that the rate of contralateral prophylactic mastectomy for unilateral breast cancers performed at a single institution serving a largely rural population has nearly tripled over the last two decades, with half of these patients having no factors that increase the risk for developing contralateral breast cancers. Contralateral prophylactic mastectomy was significantly associated with smaller tumors, younger age, genetic testing, germline pathogenic variants, family history of breast cancer, breast reconstruction, and increased wound infections.

Increased risk of contralateral breast cancer for BRCA1/2 wild-type, high-risk Korean breast cancer patients: a retrospective cohort study

BACKGROUND

This study aimed to investigate the contralateral breast cancer (CBC) recurrence rate in Korean breast cancer patients according to their BRCA1/2 germline mutation status, focusing particularly on the CBC recurrence risk in BRCA1/2 negative (BRCAx) patients.

METHODS

We conducted a retrospective study on 13,107 primary breast cancer patients. The patients were divided into high-risk and low-risk groups for hereditary breast cancer based on the Korean National Health Insurance Service's eligibility criteria for BRCA1/2 germline mutation testing. The high-risk group was further categorized into the BRCA mutation group, the BRCAx group, and the not tested group. We evaluated the overall survival and cumulative risk of developing CBC in these patients.

RESULTS

Among 4494 high-risk patients, 973 (21.7%) underwent genetic testing for BRCA1/2 germline mutation, revealing mutations in 158 patients (16.2%). We observed significant overall survival differences across all four groups, with the high-risk, not-tested group demonstrating notably worse overall survival (p < 0.001). However, when adjusted for other prognostic factors, there was no significant differences in hazard ratio of death between the four groups. The cumulative risk of CBC also varied among the groups. Patients with BRCA1/2 mutations showed a 7.3-fold increased risk of CBC compared to the low-risk group (95% CI 4.11-13.0, p < 0.001). Interestingly, BRCAx patients also demonstrated a significantly higher risk of CBC (HR 2.77, 95% CI 1.76-4.35, p < 0.001). The prognostic importance of the BRCAx for CBC recurrence persisted after adjusting for the age and subtype, but became insignificant when the family history of breast cancer was adjusted.

CONCLUSION

Breast cancer patients who are at high risk of hereditary breast cancer but with wild-type BRCA 1/2 genes (BRCAx) have increased risk of developing contralateral breast cancer when compared to the low-risk patients. More careful surveillance and follow-up can be offered to these patients especially when they have family history of breast cancer.

Age-Related Incidence and Peak Occurrence of Contralateral Breast Cancer

Importance

Young patients with breast cancer have higher risk for developing contralateral breast cancer (CBC) and have epidemiologic characteristics different from those of older patients.

Objective

To examine the incidence and peak occurrence of CBC according to age at primary breast cancer (PBC) surgery.

Design, Setting, and Participants

This cohort study included patients who were diagnosed with and underwent surgery for unilateral nonmetastatic breast cancer at Asan Medical Center, Korea, between January 1, 1999, and December 31, 2013, with follow-up through December 31, 2018. Data were analyzed from December 1, 2021, through April 30, 2023. Patients were divided into 2 groups according to their age at surgery for PBC: younger (≤35 years) vs older (>35 years).

Main Outcomes and Measures

The main outcomes were cumulative incidence and hazard rate of CBC in the entire study population and in subgroups divided by cancer subtype, categorized according to hormone receptor (HR) and ERBB2 status.

Results

A total of 16 251 female patients with stage 0 to III breast cancer were analyzed; all patients were Korean. The mean (SD) age was 48.61 (10.06) years; 1318 patients (8.11%) were in the younger group, and 14 933 (91.89%) were in the older group. Median follow-up was 107 months (IQR, 79-145 months). Compared with the older group, the younger group had significantly higher incidence of CBC (10-year cumulative incidence, 7.1% vs 2.9%; P < .001) and higher risk (hazard ratio, 2.10; 95% CI, 1.62-2.74) of developing CBC. The hazard rate, which indicates risk for developing CBC at a certain time frame, differed according to the subtype of primary cancer. In patients with the HR+/ERBB2- subtype, the risk increased continuously in both age groups. In patients with the triple negative subtype, the risk increased until approximately 10 years and then decreased in both age groups. Meanwhile, in the HR-/ERBB2+ subtype, risk peaked earlier, especially in the younger group (1.7 years since first surgery in the younger group and 4.8 years in the older group).

Conclusions and Relevance

In this cohort study, patients aged 35 years or younger with breast cancer had a higher risk of developing CBC than older patients. Moreover, young patients with the HR-/ERBB2+ subtype tended to have a shorter interval for developing CBC. These findings might be useful in guiding treatment decisions, such as contralateral prophylactic mastectomy.

A common variant SNP rs1937810 in the MPP7 gene contributes to the susceptibility of breast cancer in the Chinese Han population

BACKGROUND

Breast cancer (BC) is common cancer caused by environmental factors and genetic ones. Previous evidence has linked gene MAGUK P55 Scaffold Protein 7 (MPP7) to BC, despite that there has been no research evaluating the relationship between MPP7 genetic polymorphisms and BC susceptibility. We aimed to investigate the potential association of the MPP7 gene with the susceptibility to BC in Han Chinese individuals.

METHODS

In total, 1390 patients with BC and 2480 controls were enrolled. For genotyping, 20 tag SNPs were chosen. The serum levels of protein MPP7 were measured in all subjects using an enzyme-linked immunosorbent assay. Genetic association analysis was performed in both genotypic and allelic modes, and the relationship between BC patients' clinical features and genotypes of relevant SNPs was examined. The functional implications of significant markers were also evaluated.

RESULTS

After adjusting for Bonferroni correction, SNP rs1937810 was found to be significantly associated with the risk of BC (p = 1.19 × 10-4 ). The odds ratio of CC genotypes in BC patients was 49% higher than in controls (1.49 [1.23-1.81]). Serum MPP7 protein levels were significantly higher in BC patients than in controls (p < 0.001). The protein level of the CC genotype was the highest, and that of the CT and TT genotypes decreased in turn (both p < 0.001).

CONCLUSIONS

Our results linked SNP rs1937810 to the susceptibility of BC and the clinical features of BC patients. This SNP is also proved to be significantly related to the serum level of protein MPP7 in both BC patients and controls.

BRCA-CRisk: A Contralateral Breast Cancer Risk Prediction Model for BRCA Carriers

PURPOSE

The absolute cumulative risk of contralateral breast cancer (CBC) for patients with BRCA1/2 variants is unknown. The purpose of this study was to develop a CBC risk prediction model for assessing CBC risk for BRCA1/2 carriers.

METHODS

The primary cohort of 491 patients with BRCA1/2 variants was derived from a large series of unselected patients with breast cancer. A nomogram was established on the basis of the results of a multivariate Cox regression analysis from this cohort. This model, named BRCA-CRisk, was further validated by an independent cohort of 205 patients with BRCA1/2 variants. Discrimination and calibration of the model were assessed.

RESULTS

In the primary cohort of 491 patients, 66 developed contralateral breast cancer after a median follow-up of 7.0 years. Four variables were significantly associated with risk of CBC and were incorporated in the establishment of the BRCA-CRisk prediction model: younger age at first breast cancer (with continuous variable, P = .002), positive first-degree family history of breast and/or ovarian cancer (hazard ratio [HR], 1.89; 95% CI, 1.16 to 3.08; P = .011), variant located near the 3' region of BRCA (HR, 2.01; 95% CI, 1.23 to 3.30; P = .006), and endocrine therapy (HR, 0.54; 95% CI, 0.33 to 0.88; P = .013). The area under the time-dependent curves for the 5- and 10-year cumulative risks of CBC were 0.775 and 0.702, respectively. The model was well validated in the independent cohort of 205 BRCA1/2 carriers, with area under the curves of 0.750 and 0.691 for 5 and 10 years, respectively.

CONCLUSION

BRCA-CRisk model provides a useful tool for assessing the absolute cumulative risk of CBC for BRCA1/2 carriers and may help carriers and clinicians optimally select risk-reducing strategies on the basis of individual CBC risk.

The Contribution of Germline Pathogenic Variants in Breast Cancer Genes to Contralateral Breast Cancer Risk in BRCA1/BRCA2/PALB2-Negative Women

BACKGROUND

Contralateral breast cancer (CBC) is associated with younger age at first diagnosis, family history and pathogenic germline variants (PGVs) in genes such as BRCA1, BRCA2 and PALB2. However, data regarding genetic factors predisposing to CBC among younger women who are BRCA1/2/PALB2-negative remain limited.

METHODS

In this nested case-control study, participants negative for BRCA1/2/PALB2 PGVs were selected from the WECARE Study. The burden of PGVs in established breast cancer risk genes was compared in 357 cases with CBC and 366 matched controls with unilateral breast cancer (UBC). The samples were sequenced in two phases. Whole exome sequencing was used in Group 1, 162 CBC and 172 UBC (mean age at diagnosis: 42 years). A targeted panel of genes was used in Group 2, 195 CBC and 194 UBC (mean age at diagnosis: 50 years). Comparisons of PGVs burdens between CBC and UBC were made in these groups, and additional stratified sub-analysis was performed within each group according to the age at diagnosis and the time from first breast cancer (BC).

RESULTS

The PGVs burden in Group 1 was significantly higher in CBC than in UBC (p = 0.002, OR = 2.5, 95CI: 1.2-5.6), driven mainly by variants in CHEK2 and ATM. The proportions of PGVs carriers in CBC and UBC in this group were 14.8% and 5.8%, respectively. There was no significant difference in PGVs burden between CBC and UBC in Group 2 (p = 0.4, OR = 1.4, 95CI: 0.7-2.8), with proportions of carriers being 8.7% and 8.2%, respectively. There was a significant association of PGVs in CBC with younger age. Metanalysis combining both groups confirmed the significant association between the burden of PGVs and the risk of CBC (p = 0.006) with the significance driven by the younger cases (Group 1).

CONCLUSION

In younger BRCA1/BRCA2/PALB2-negative women, the aggregated burden of PGVs in breast cancer risk genes was associated with the increased risk of CBC and was inversely proportional to the age at onset.

Synchronous and metachronous bilateral breast cancer among women with a history of lobular carcinoma in situ

PURPOSE

Lobular carcinoma in situ (LCIS) confers increased cancer risk in either breast, but it remains unclear if this population is at increased risk for bilateral breast cancer (BC) development. Here we report bilateral BC incidence among women with a history of LCIS.

METHODS

Women with classic-type LCIS diagnosed from 1980 to 2017 who developed unilateral BC (UBC) or bilateral BC were identified. Bilateral BC was categorized as synchronous (bilateral BC diagnosed < 6 months apart; SBBC) or metachronous (bilateral BC diagnosed ≥ 6 months apart; MBBC). Five-year incidence rates of bilateral BC among this population were evaluated. Comparisons were made to identify factors associated with bilateral BC.

RESULTS

At 7 years' median follow-up, 249/1651 (15%) women with LCIS developed BC; 34 with bilateral BC (2%). There were no clinicopathologic feature differences between those with UBC and bilateral BC. SBBC occurred in 18 without significant differences versus UBC. Among 211 with UBC and a contralateral breast at risk, 16 developed MBBC at a median follow-up of 3 years. MBBC patients were less likely to receive endocrine therapy and more likely to receive chemotherapy versus UBC. Tumor histology was not associated with MBBC. Estimated 5-year MBBC risk was 6.4%. Index estrogen/progesterone receptor positivity and endocrine therapy were the only factors associated with MBBC risk.

CONCLUSION

Bilateral BC occurred in 2% of women with LCIS history at median follow-up of 7 years. Similar to the general BC population, a decrease in MBBC is seen among women with a history of LCIS who develop hormone receptor-positive disease and those who receive endocrine therapy, highlighting the protective effects of this treatment.

Timely cancer genetic counseling and testing for young women with breast cancer: impact on surgical decision-making for contralateral risk-reducing mastectomy

PURPOSE

Genetic testing (GT) can identify individuals with pathogenic/likely pathogenic variants (PV/LPVs) in breast cancer (BC) predisposition genes, who may consider contralateral risk-reducing mastectomy (CRRM). We report on CRRM rates in young women newly diagnosed with BC who received GT through a multidisciplinary clinic.

METHODS

Clinical data were reviewed for patients seen between November 2014 and June 2019. Patients with non-metastatic, unilateral BC diagnosed at age ≤ 45 and completed GT prior to surgery were included. Associations between surgical intervention and age, BC stage, family history, and GT results were evaluated.

RESULTS

Of the 194 patients, 30 (15.5%) had a PV/LPV in a BC predisposition gene (ATM, BRCA1, BRCA2, CHEK2, NBN, NF1), with 66.7% in BRCA1 or BRCA2. Of 164 (84.5%) uninformative results, 132 (68%) were negative and 32 (16.5%) were variants of uncertain significance (VUS). Overall, 67 (34.5%) had CRRM, including 25/30 (83.3%) PV/LPV carriers and 42/164 (25.6%) non-carriers. A positive test result (p < 0.01) and significant family history were associated with CRRM (p = 0.02). For the 164 with uninformative results, multivariate analysis showed that CRRM was not associated with age (p = 0.23), a VUS, (p = 0.08), family history (p = 0.10), or BC stage (p = 0.11).

CONCLUSION

In this cohort of young women with BC, the identification of a PV/LPV in a BC predisposition gene and a significant family history were associated with the decision to pursue CRRM. Thus, incorporation of genetic services in the initial evaluation of young patients with a new BC could contribute to the surgical decision-making process.

The impact of young age (< 40 years) on the outcome of a cohort of patients with primary non-metastatic breast cancer: analysis of 10-year survival of a prospective study

Background

The role of young age (< 40 years) at diagnosis as an independent risk factor for adverse outcomes in female patients with breast cancer has been highlighted in several studies. In this prospective study, we assessed the difference in 10-year survival between two groups of patients diagnosed with non-metastatic breast cancer based on an age cutoff of 40 years. We also assessed the impact of factors including tumor characteristics, molecular markers and immunohistochemical markers on survival outcomes, highlighting the interaction of those variables with age.

Methods

A total of 119 female patients with newly diagnosed non-metastatic breast cancer were recruited at the American University of Beirut Medical Center (AUBMC) between July 2011 and May 2014. Patients were recruited and divided into 2 age groups (< 40 and ≥ 40 years). In addition to clinical characteristics, we assessed immunohistochemistry including estrogen, progesterone and HER2 receptors, p53, cyclin B1, vascular endothelial growth factor receptor (VEGFR), and ki-67. Germline BRCA mutations were also performed on peripheral blood samples. Patient and tumor characteristics were compared between the age groups. 10-year overall survival (OS) and disease-free survival (DFS) were estimated accordingly. Cox regression analysis was performed in order to assess the effect of the different variables on clinical outcomes.

Results

After a median Follow-up of 96 (13–122) months, the estimated 10-year OS was 98.6% for patients ≥40 as compared to 77.6% in patients < 40 (p = 0.001). A similar trend was found for 10-year DFS reaching 90% for patients ≥40 and 70.4% for those < 40 (p = 0.004). On multivariate analysis for DFS and OS, only younger age (< 40 years), higher stage and triple negative phenotype among other parameters assessed significantly affected the outcome in this cohort.

Conclusion

This prospective study confirms the association between younger age and adverse survival outcomes in patients with non-metastatic breast cancer. Future studies of the whole genome sequences may reveal the genomic basis underlying the clinical differences we have observed.

Is there an increasing trend of risk-reducing prophylactic mastectomy procedure in preventing breast cancer among women?

Objectives

Prophylactic contralateral/bilateral mastectomy (PCM/PBM), as a risk-reducing mastectomy procedure, has a few evidence-based indica- tions; however, there is an increasing trend in the total number of operations globally. Worldwide famous actress Angelina Jolie was detected to have BRCA-1 mutation and underwent a prophylactic bilateral mastectomy in 2013. The procedure was perceived as 'lifesaving' worldwide, which eventually led to a significant increase in BRCA gene mutation analysis and PCM/PBM. In this study, it was aimed to evaluate our risk-reducing PCM/PBM results.

Material and Methods

Twenty-seven patients underwent risk-reducing PCM/PBM between 2010-2018, but only 22 patients were included into the study. A retrospective analysis was carried out on demographics, family history, preoperative diagnoses, pathological findings, mastectomy details, reconstructive procedures, neoadjuvant chemotherapy, BRCA analysis, educational status, and mastectomy indications.

Results

Surgical indications or major reasons for surgery were as follows: BRCA-1 mutation (n= 5), BRCA-2 mutation (n= 3), malignant-like areas in magnetic resonance imaging (n= 2), lobular carcinoma in situ (n= 3) and intense anxiety (n= 9). Eighteen patients (82%) underwent an additional re- constructive procedure via implantation or autologous tissue and four patients (18%) underwent mastectomy only. PCM/PBM by years was as: 2010 (n= 1), 2011 (n= 0), 2012 (n= 1), 2013 (n= 2), 2014 (n= 1), 2015 (n= 2), 2016 (n= 3), 2017 (n= 4), 2018 (n= 8), which represents the recently increasing trend.

Conclusion

Risk-reducing PCM/PBM was performed in 59.1% of the patients (n= 13) for a significant medical reason, whereas for distress about a relapse or a new disease on the contralateral breast on the remaining 40.9% of the patients (n= 9). Evidence in the literature shows that risk-reducing mastectomy does not affect survival, although it lowers breast cancer incidence. Close surveillance, cancer screening, and chemoprevention methods should have priority.

Coronary Artery Disease in Young Women After Radiation Therapy for Breast Cancer: The WECARE Study

Background

Radiation therapy (RT) for breast cancer increases risk of coronary artery disease (CAD). Women treated for left- vs right-sided breast cancer receive greater heart radiation exposure, which may further increase this risk. The risk of radiation-associated CAD specifically among younger breast cancer survivors is not well defined.

Objectives

The purpose of this study was to report CAD risk among participants in the Women's Environmental Cancer and Radiation Epidemiology Study.

Methods

A total of 1,583 women who were <55 years of age when diagnosed with breast cancer between 1985 and 2008 completed a cardiovascular health questionnaire. Risk of radiation-associated CAD was evaluated by comparing women treated with left-sided RT with women treated with right-sided RT using multivariable Cox proportional hazards models. Effect modification by treatment and cardiovascular risk factors was examined.

Results

In total, 517 women who did not receive RT and 94 women who had a pre-existing cardiovascular disease diagnosis were excluded, leaving 972 women eligible for analysis. Their median follow-up time was 14 years (range 1-29 years). The 27.5-year cumulative incidences of CAD for women receiving left- vs right-sided RT were 10.5% and 5.8%, respectively (P = 0.010). The corresponding HR of CAD for left- vs right-sided RT in the multivariable Cox model was 2.5 (95% CI: 1.3-4.7). There was no statistically significant effect modification by any factor evaluated.

Conclusions

Young women treated with RT for left-sided breast cancer had over twice the risk of CAD compared with women treated with RT for right-sided breast cancer. Laterality of RT is independently associated with an increased risk of CAD and should be considered in survivorship care of younger breast cancer patients.

Risk factors for contralateral breast cancer in postmenopausal breast cancer survivors in the NIH-AARP Diet and Health Study

PURPOSE

The role of established breast cancer risk factors and clinical characteristics of the first breast cancer in the development of contralateral breast cancer (CBC) among postmenopausal women is unclear.

METHODS

We identified 10,934 postmenopausal women diagnosed with a first primary breast cancer between 1995 and 2011 in the NIH-AARP Diet and Health Study. CBC was defined as a second primary breast cancer diagnosed in the contralateral breast ≥ 3 months after the first breast cancer. Exposures included pre-diagnosis risk factors (lifestyle, reproductive, family history) and clinical characteristics of the first breast cancer. We used multivariable Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Over a median follow-up of 6.8 years, 436 women developed CBC. We observed an increasing trend in CBC risk by age (p-trend = 0.002) and decreasing trend by year of diagnosis (p-trend = 0.001) of the first breast cancer. Additional risk factor associations were most pronounced for endocrine therapy (HR 0.68, 95% CI 0.53-0.87) and family history of breast cancer (HR 1.38, 95% CI 1.06-1.80, restricted to invasive first breast cancer). No associations were found for lifestyle (body mass index, physical activity, smoking, alcohol) or reproductive factors (age at menarche, parity, age at first birth, age at menopause).

CONCLUSIONS

This study suggests that clinical characteristics of the first breast cancer and family history of breast cancer, but not pre-diagnosis lifestyle and reproductive factors, are strongly associated with CBC risk among postmenopausal women. Future studies are needed to understand how these factors contribute to CBC etiology and to identify further opportunities for prevention.

Second primary breast cancer after unilateral mastectomy alone or with contralateral prophylactic mastectomy

Background

An increasing number of patients undergo contralateral prophylactic mastectomy (CPM) for unilateral breast cancer. However, the benefit of CPM has not been quantified in the setting of contemporary breast cancer therapy.

Methods

We performed an analysis of 180 068 patients in the Surveillance, Epidemiology, and End Results (SEER) database, diagnosed with unilateral ductal breast carcinoma between 1998 and 2013 and treated with unilateral mastectomy (UM) or CPM. UM was performed in 146 213 patients (81.2%); CPM was performed in 33 855 patients (19.8%). Primary outcome of interest was cumulative incidence of a second primary breast cancer in the ipsilateral or contralateral breast greater than 3 months after initial diagnosis. Cumulative incidence analysis was based on a Cox proportional model to generate curves of second primary breast cancer in any breast, ipsilateral breast only, or contralateral breast only.

Results

Patients who underwent CPM had a significantly reduced incidence of second primary breast cancer 10 and 15 years after surgery (CPM 0.93% [0.73%, 1.12%] vs UM 4.44% [4.28%, 4.60%]). Patients who underwent CPM had significantly lower adjusted hazard of second primary breast cancer when compared with UM (HR 0.38 vs 1.0, P < .0001).

Conclusions

CPM offers some protection from a second primary breast cancer, attributable to a reduced incidence in the contralateral breast. These findings provide additional information to providers and patients as they make decisions regarding surgical management. They should also be interpreted in the context of the absolute incidence of second primary breast cancer after UM and previous literature demonstrating no survival benefit.

Is prophylactic mastectomy justified in women without BRCA mutation?

In the past decades the demand for prophylactic mastectomies has increased substantially. For healthy non high risk germ line mutation carriers there is no real objective justification for such a procedure, and screening according established evidence based guidelines is strongly advised. More demand for contralateral prophylactic mastectomy is coming from women diagnosed with breast cancer. First counseling and appropriate germ line gene mutation testing has to be established. In absence of high risk mutations, breast conservation therapy for the diagnosed breast cancer is as good as mastectomy, and the risk of a contralateral breast cancer is low (0.3-0.6% per annum follow up). So bilateral mastectomy will not provide any survival benefit and is associated with worsened body image and QoL, and more complications and re-operations as compared to breast conservation followed by screening. The patient asking for a CPM deserves careful counseling and a shared decision process.

Contralateral prophylactic mastectomy in breast cancer: what to discuss with patients

Introduction: The contralateral prophylactic mastectomy (CPM) rate in the U.S. has been steadily increasing. This is of particular concern because many women who undergo this procedure are candidates for breast-conserving surgery.Areas covered: CPM's medical benefit is related to the risk of contralateral cancer development and whether CPM provides a survival benefit. Contralateral cancer rates have decreased, and CPM does not provide a survival benefit. Other potential benefits of the procedure may be improved quality of life; these data are reviewed. Research efforts have been undertaken to better understand the decision-making process of patients who consider, and ultimately undergo, this procedure.Expert opinion: Decisional traits, personal values, the desire for peace of mind, and the desire to obtain breast symmetry are important factors that drive a woman's decision to undergo CPM. Additionally, many patients lack the knowledge on how different types of breast surgery impact outcomes. To improve the shared decision-making process, a stepwise approach to address possible misconceptions, and clarify the real risks/benefits of this procedure should be utilized. A clear recommendation (for/against) should be made for every patient with newly diagnosed breast cancer who considers CPM. Communication tools to assist patients and surgeons in this process are sorely needed.

Machine learning on genome-wide association studies to predict the risk of radiation-associated contralateral breast cancer in the WECARE Study

The purpose of this study was to identify germline single nucleotide polymorphisms (SNPs) that optimally predict radiation-associated contralateral breast cancer (RCBC) and to provide new biological insights into the carcinogenic process. Fifty-two women with contralateral breast cancer and 153 women with unilateral breast cancer were identified within the Women’s Environmental Cancer and Radiation Epidemiology (WECARE) Study who were at increased risk of RCBC because they were ≤ 40 years of age at first diagnosis of breast cancer and received a scatter radiation dose > 1 Gy to the contralateral breast. A previously reported algorithm, preconditioned random forest regression, was applied to predict the risk of developing RCBC. The resulting model produced an area under the curve (AUC) of 0.62 (p = 0.04) on hold-out validation data. The biological analysis identified the cyclic AMP-mediated signaling and Ephrin-A as significant biological correlates, which were previously shown to influence cell survival after radiation in an ATM-dependent manner. The key connected genes and proteins that are identified in this analysis were previously identified as relevant to breast cancer, radiation response, or both. In summary, machine learning/bioinformatics methods applied to genome-wide genotyping data have great potential to reveal plausible biological correlates associated with the risk of RCBC.

Contralateral Prophylactic Mastectomy in Women with Unilateral Breast Cancer Who Are Genetic Carriers, Have a Strong Family History or Are just Young at Presentation

The uptake of contralateral prophylactic mastectomy is rising with increasing trends that are possibly highest in the USA. Whilst its role is generally accepted in carriers of recognized high-risk predisposition genes such as BRCA1 and BRCA2 when the affected individual is premenopausal, controversy surrounds the benefit in less understood risk-profile clinical scenarios. This comprehensive review explores the current evidence underpinning the role of contralateral prophylactic mastectomy and its impact on contralateral breast cancer risk and survival in three distinct at-risk groups affected by unilateral breast cancer: known genetic carriers, those with strong familial risk but no demonstrable genetic mutation and women who are of young age at presentation. The review supports the role of contralateral prophylactic mastectomy in "high risk" groups where the evidence suggests a reduction in contralateral breast cancer risk. However, this benefit is less evident in women who are just young at presentation or those who have strong family history but no demonstrable genetic mutation. A multidisciplinary and personalized approach to support individuals in a shared-decision making process is recommended.

Impact of genetic counseling on the uptake of contralateral prophylactic mastectomy among younger women with breast cancer

Background: Preoperative genetic testing affects the surgical decision-making among women with breast cancer. To avoid breast-conserving surgery and to offer the possibility of mastectomy with immediate reconstruction in high-risk patients, genetic testing for pathogenic variants in BRCA1 or BRCA2 and a pedigree-based familial breast cancer risk assessment was offered to younger women with breast cancer in Denmark. We evaluated the impact of the risk stratification through genetic counseling on the uptake of contralateral prophylactic mastectomy (CPM).Material and methods: The prospective cohort study included all women with unilateral breast cancer before the age of 45 who participated in a genetic counseling program during their primary diagnostics in the Central Denmark Region (2013-2018). Each patient was followed from the time of the genetic test result to the end of follow-up to estimate the long-term uptake of CPM as a competing risk-adjusted cumulative incidence. We compared the uptake of CPM between the various genetic risk categories, ages of onset, and family histories in a multivariable Cox proportional hazards regression model, reporting hazard ratios (HR) with two-sided 95% confidence intervals (CIs).Results: 156 females, aged 21-44, learned their genetic test result within a median of 92 days [interquartile range (IQR): 75-114]. The maximal follow-up was 3.8 years (median 1.8; IQR: 0.49-2.5), after which 33% (95% CI: 24-42%) of the patients had undergone CPM. The uptake of CPM was inversely associated with the age of onset (HR 0.92; 95% CI: 0.86-0.98) and significantly higher among BRCA carriers (HR 2.9; 95% CI: 1.3-6.8) and patients from the high risk of breast cancer families (HR 5.6; 95% CI: 1.9-16) compared to the lower genetic risk categories.Conclusion: The risk stratification obtained through genetic counseling had a considerable impact on the surgical decision-making among younger women with breast cancer at long-term follow-up.

Contralateral Breast Cancer and Ipsilateral Breast Tumor Recurrence in BRCA1/2 Carriers and Non-Carriers at High-Risk of Hereditary Breast Cancer

Purpose

We evaluated the risk of contralateral breast cancer (CBC) and ipsilateral breast tumor recurrence (IBTR) and investigated the predictive factors for CBC and IBTR in breast cancer patients with BRCA mutations and non-carriers at high-risk of hereditary breast and ovarian cancer (HBOC).

Methods

We analyzed prospectively collected clinical data of patients with unilateral breast cancer who were at high-risk for HBOC and were tested for the BRCA mutation between 2003 and 2013.

Results

The cohort comprised 540 patients with 45 BRCA1 carriers, 50 BRCA2 carriers, and 445 non-carriers. The median follow-up was 84.5 months. Overall, 61 patients (11.3%) developed CBC (24.4% for BRCA1 carriers, 20% for BRCA2 carriers, and 9% for non-carriers). The 10-year cumulative risk for CBC was 23.8% for BRCA1 carriers, 19.1% for BRCA2 carriers, and 9.8% for non-carriers (p = 0.174). Among the 277 patients who underwent breast-conserving surgery, 29 (10.5%) developed IBTR (9.1% for BRCA1 carriers, 16.7% for BRCA2 carriers, and 10.2% for non-carriers). The 10-year cumulative risk for IBTR for BRCA1 carriers, BRCA2 carriers, and non-carriers was 8.7%, 14.1%, and 20%, respectively (p = 0.577). BRCA1 (hazard ratio [HR], 2.94; 95% confidence interval [CI], 1.20-7.20; p = 0.019) and BRCA2 (HR, 2.88; 95% CI, 1.13-7.35; p = 0.027) mutations and negative estrogen receptor status (HR, 4.02; 95% CI, 1.60-10.08; p = 0.003) were the significant predictive factors for CBC, while tumor size ≥ 2 cm was predictive of IBTR (HR, 6.11; 95% CI, 2.03-18.33; p = 0.001).

Conclusion

While BRCA1/2 mutation carriers had a higher risk of developing CBC compared to non-carriers at high-risk of HBOC, the risk of IBTR was similarly high across breast cancer patients irrespective of the BRCA mutation. Further preventive strategies to reduce CBC and IBTR for all patients at high-risk of HBOC should be investigated.

Risk of Contralateral Breast Cancer in Women with Ductal Carcinoma In Situ Associated with Synchronous Ipsilateral Lobular Carcinoma In Situ

BACKGROUND

Lobular carcinoma in situ (LCIS) is a risk factor for breast cancer, but the effect of LCIS found in association with ductal carcinoma in situ (DCIS) is unknown. In this study, we compared contralateral breast cancer (CBC) and ipsilateral breast tumor recurrence (IBTR) rates among women with DCIS with or without synchronous ipsilateral LCIS treated with breast-conserving surgery (BCS).

METHODS

DCIS patients undergoing BCS from 2000 to 2011 with a contralateral breast at risk were stratified by the presence or absence of synchronous ipsilateral LCIS with the index DCIS (DCIS + LCIS vs. DCIS). Those with contralateral, bilateral, or prior ipsilateral LCIS were excluded. Associations of patient, tumor, and treatment factors with CBC and IBTR were evaluated.

RESULTS

Of 1888 patients identified, 1475 (78%) had DCIS and 413 (22%) had DCIS + LCIS. At median follow-up of 7.2 (range 0-17) years, 307 patients had a subsequent first breast event; 207 IBTR and 100 CBC. The 10-year cumulative incidence of IBTR was similar in both groups: 15.0% vs. 14.2% (log-rank, p = 0.8) for DCIS + LCIS vs. DCIS, respectively. The 10-year cumulative incidence of CBC was greater in the DCIS + LCIS group: 10.9% vs. 6.1% for DCIS (log-rank, p < 0.001). After adjustment for other factors, CBC risk remained higher in DCIS + LCIS compared with DCIS (hazard ratio 2.06, 95% confidence interval 1.36-3.11, p = 0.001); there was no significant difference in IBTR risk.

CONCLUSIONS

Compared with DCIS alone, DCIS + LCIS is associated with similar IBTR risk but double the risk of CBC. This finding should inform treatment decisions, in particular regarding endocrine therapy for risk reduction.

Association of a Pathway-Specific Genetic Risk Score With Risk of Radiation-Associated Contralateral Breast Cancer

IMPORTANCE

Radiation therapy for breast cancer is associated with increased risk of a second primary contralateral breast cancer, but the genetic factors modifying this association are not well understood.

OBJECTIVE

To determine whether a genetic risk score comprising single nucleotide polymorphisms in the nonhomologous end-joining DNA repair pathway is associated with radiation-associated contralateral breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study included a case group of women with contralateral breast cancer that was diagnosed at least 1 year after a first primary breast cancer who were individually matched to a control group of women with unilateral breast cancer. Inclusion criteria were receiving a first invasive breast cancer diagnosis prior to age 55 years between 1985 and 2008. Women were recruited through 8 population-based cancer registries in the United States, Canada, and Denmark as part of the Women's Environment, Cancer, and Radiation Epidemiology Studies I (November 2000 to August 2004) and II (March 2010 to December 2012). Data analysis was conducted from July 2017 to August 2019.

EXPOSURES

Stray radiation dose to the contralateral breast during radiation therapy for the first breast cancer. A novel genetic risk score comprised of genetic variants in the nonhomologous end-joining DNA repair pathway was considered the potential effect modifier, dichotomized as high risk if the score was above the median of 74 and low risk if the score was at or below the median.

MAIN OUTCOMES AND MEASURES

The main outcome was risk of contralateral breast cancer associated with stray radiation dose stratified by genetic risk score, age, and latency.

RESULTS

A total of 5953 women were approached for study participation, and 3732 women (62.7%) agreed to participate. The median (range) age at first diagnosis was 46 (23-54) years. After 5 years of latency or more, among women who received the first diagnosis when they were younger than 40 years, exposure to 1.0 Gy (to convert to rad, multiply by 100) or more of stray radiation was associated with a 2-fold increased risk of contralateral breast cancer compared with women who were not exposed (rate ratio, 2.0 [95% CI, 1.1-3.6]). The risk was higher among women with a genetic risk score above the median (rate ratio, 3.0 [95% CI, 1.1-8.1]), and there was no association among women with a genetic risk score below the median (rate ratio, 1.3 [95% CI, 0.5-3.7]). Among younger women with a high genetic risk score, the attributable increased risk for contralateral breast cancer associated with stray radiation dose was 28%.

CONCLUSIONS AND RELEVANCE

This study found an increased risk of contralateral breast cancer that was attributable to stray radiation exposure among women with a high genetic risk score and who received a first breast cancer diagnosis when they were younger than 40 years after 5 years or more of latency. This genetic risk score may help guide treatment and surveillance for women with breast cancer.

Breast cancer risk in BRCA1/2 mutation carriers and noncarriers under prospective intensified surveillance

Comparably little is known about breast cancer (BC) risks in women from families tested negative for BRCA1/2 mutations despite an indicative family history, as opposed to BRCA1/2 mutation carriers. We determined the age-dependent risks of first and contralateral breast cancer (FBC, CBC) both in noncarriers and carriers of BRCA1/2 mutations, who participated in an intensified breast imaging surveillance program. The study was conducted between January 1, 2005, and September 30, 2017, at 12 university centers of the German Consortium for Hereditary Breast and Ovarian Cancer. Two cohorts were prospectively followed up for incident FBC (n = 4,380; 16,398 person-years [PY], median baseline age: 39 years) and CBC (n = 2,993; 10,090 PY, median baseline age: 42 years). Cumulative FBC risk at age 60 was 61.8% (95% CI 52.8-70.9%) for BRCA1 mutation carriers, 43.2% (95% CI 32.1-56.3%) for BRCA2 mutation carriers and 15.7% (95% CI 11.9-20.4%) for noncarriers. FBC risks were significantly higher than in the general population, with incidence rate ratios of 23.9 (95% CI 18.9-29.8) for BRCA1 mutation carriers, 13.5 (95% CI 9.2-19.1) for BRCA2 mutation carriers and 4.9 (95% CI 3.8-6.3) for BRCA1/2 noncarriers. Cumulative CBC risk 10 years after FBC was 25.1% (95% CI 19.6-31.9%) for BRCA1 mutation carriers, 6.6% (95% CI 3.4-12.5%) for BRCA2 mutation carriers and 3.6% (95% CI 2.2-5.7%) for noncarriers. CBC risk in noncarriers was similar to women with unilateral BC from the general population. Further studies are needed to confirm whether less intensified surveillance is justified in women from BRCA1/2 negative families with elevated risk.

Contralateral prophylactic mastectomy in women with breast cancer without a family history or genetic predisposition : Consensus statement from the Austrian Gynecologic Oncology Working Group of the Austrian Society of Obstetrics and Gynecology

The working group recommends against contralateral prophylactic mastectomy (CPM) in women with breast cancer without a family history or genetic predisposition with unilateral breast cancer. This is based on the low risk of developing contralateral breast cancer, the lack of a survival benefit, the increased risk of surgical complications, and the lack of benefit on quality of life.

CYP2D6 phenotype, tamoxifen, and risk of contralateral breast cancer in the WECARE Study

BACKGROUND

Tamoxifen treatment greatly reduces a woman's risk of developing a second primary breast cancer. There is, however, substantial variability in treatment response, some of which may be attributed to germline genetic variation. CYP2D6 is a key enzyme in the metabolism of tamoxifen to its active metabolites, and variants in this gene have been associated with reduced tamoxifen metabolism. The impact of variation on risk of contralateral breast cancer (CBC) is unknown.

METHODS

Germline DNA from 1514 CBC cases and 2203 unilateral breast cancer controls was genotyped for seven single nucleotide polymorphisms, one three-nucleotide insertion-deletion, and a full gene deletion. Each variant has an expected impact on enzyme activity, which in combination allows for the classification of women as extensive, intermediate, and poor metabolizers (EM, IM, and PM respectively). Each woman was assigned one of six possible diplotypes and a corresponding CYP2D6 activity score (AS): EM/EM (AS = 2), EM/IM (AS = 1.5), EM/PM (AS = 1), IM/IM (AS = 0.75), IM/PM (AS = 0.5), and PM/PM (AS = 0). We also collapsed categories of the AS to generate an overall phenotype (EM, AS ≥ 1; IM, AS = 0.5-0.75; PM, AS = 0). Rate ratios (RRs) and 95% confidence intervals (CIs) for the association between tamoxifen treatment and risk of CBC in our study population were estimated using conditional logistic regression, stratified by AS.

RESULTS

Among women with AS ≥ 1 (i.e., EM), tamoxifen treatment was associated with a 20-55% reduced RR of CBC (AS = 2, RR = - 0.81, 95% CI 0.62-1.06; AS = 1.5, RR = 0.45, 95% CI 0.30-0.68; and AS = 1, RR = 0.55, 95% CI 0.40-0.74). Among women with no EM alleles and at least one PM allele (i.e., IM and PM), tamoxifen did not appear to impact the RR of CBC in this population (AS = 0.5, RR = 1.08, 95% CI 0.59-1.96; and AS = 0, RR = 1.17, 95% CI 0.58-2.35) (p for homogeneity = - 0.02).

CONCLUSION

This study suggests that the CYP2D6 phenotype may contribute to some of the observed variability in the impact of tamoxifen treatment for a first breast cancer on risk of developing CBC.

Risk factors for metachronous contralateral breast cancer: A systematic review and meta-analysis

BACKGROUND

The risk of developing metachronous contralateral breast cancer (CBC) is a recurrent topic at the outpatient clinic. We aimed to provide CBC risk estimates of published patient, pathological, and primary breast cancer (PBC) treatment-related factors.

METHODS

PubMed was searched for publications on factors associated with CBC risk. Meta-analyses were performed with grouping of studies by mutation status (i.e., BRCA1, BRCA2, CHEK2 c.1100delC), familial cohorts, and general population-based cohorts.

RESULTS

Sixty-eight papers satisfied our inclusion criteria. Strong associations with CBC were found for carrying a BRCA1 (RR = 3.7; 95%CI:2.8-4.9), BRCA2 (RR = 2.8; 95%CI:1.8-4.3) or CHEK2 c.1100delC (RR = 2.7; 95%CI:2.0-3.7) mutation. In population-based cohorts, PBC family history (RR = 1.8; 95%CI:1.2-2.6), body mass index (BMI) ≥30 kg/m² (RR = 1.5; 95%CI:1.3-1.9), lobular PBC (RR = 1.4; 95%CI:1.1-1.8), estrogen receptor-negative PBC (RR = 1.5; 95%CI:1.0-2.3) and treatment with radiotherapy <40 years (RR = 1.4; 95%CI:1.1-1.7) was associated with increased CBC risk. Older age at PBC diagnosis (RR per decade = 0.93; 95%CI:0.88-0.98), and treatment with chemotherapy (RR = 0.7; 95%CI:0.6-0.8) or endocrine therapy (RR = 0.6; 95%CI:0.5-0.7) were associated with decreased CBC risk.

CONCLUSIONS

Mutation status, family history, and PBC treatment are key factors for CBC risk. Age at PBC diagnosis, BMI, lobular histology and hormone receptor status have weaker associations and should be considered in combination with key factors to accurately predict CBC risk.

Breast cancer in adolescents and young adults

Breast cancer is the most common cancer of adolescents and young adult (AYA) women aged 15 to 39 years, accounting for 5.6% of all invasive breast cancer in women. In comparison with older women, AYAs are more likely to have familial cancer predisposition genes, larger breast tumors, unfavorable biological characteristics, distant metastatic disease at diagnosis, and adverse outcome. Endocrine therapy and some chemotherapy recommendations differ between young and older women. AYAs require coordinated multidisciplinary care, treatment regimens that minimize late effects such as premature menopause and osteoporosis, and proactive management of psychological and sexual health during and after cancer treatment.

Breast Cancer Genetics and Indications for Prophylactic Mastectomy

As more genetic information becomes available to inform breast cancer treatment, screening, and risk-reduction approaches, clinicians must become more knowledgeable about possible genetic testing and prevention strategies, including outcomes, benefits, risks, and limitations. The aim of this article is to define and distinguish high- and moderate-risk breast cancer predisposition genes, summarize the clinical recommendations that may be considered based on the identification of pathogenic variants (mutations) in these genes, and indications for risk-reducing and contralateral prophylactic mastectomy.

Development and pilot testing of a Decision Aid (DA) for women with early-stage breast cancer considering contralateral prophylactic mastectomy

OBJECTIVE

Describe the development, acceptability and feasibility of a Decision Aid (DA) for women with early-stage breast cancer (BC) at average contralateral breast cancer (CBC) risk considering contralateral prophylactic mastectomy (CPM).

METHODS

The DA was developed using the International Patient Decision Aid Standards (IPDAS) and the Ottawa Decision Support Framework. It provides evidence-based information about CPM in a booklet format combining text, graphs and images of surgical options. Twenty-three women with a history of early-stage breast cancer were interviewed in person or over the phone using a 'think aloud approach'. Framework analysis was used to code and analyse data.

RESULTS

Twenty-three women participated in the study. Mean age of participants was 58.6 years and time since diagnosis ranged from 14 months to 21 years. Five women had CPM and eighteen had not. Women strongly endorsed the DA. Many felt validated by a section on appearance and found information on average risk of recurrence and metastases helpful, however, noted the importance of discussing personal risk with their surgeon. Many requested more information on surgery details (time taken, recovery) and costs of the different options.

CONCLUSION

The DA was acceptable to women, including the format, content and proposed implementation strategies. Practical and financial issues are important to women in considering treatment options.

PRACTICE IMPLICATIONS

Women appreciate information about CPM at diagnosis and emphasised the importance of discussing potential downsides of the procedure in addition to benefits. The DA was considered acceptable to facilitate such discussions.

Breast Cancer Family History and Contralateral Breast Cancer Risk in Young Women: An Update From the Women's Environmental Cancer and Radiation Epidemiology Study

Purpose The Women's Environmental Cancer and Radiation Epidemiology (WECARE) study demonstrated the importance of breast cancer family history on contralateral breast cancer (CBC) risk, even for noncarriers of deleterious BRCA1/2 mutations. With the completion of WECARE II, updated risk estimates are reported. Additional analyses that exclude women negative for deleterious mutations in ATM, CHEK2*1100delC, and PALB2 were performed. Patients and Methods The WECARE Study is a population-based case-control study that compared 1,521 CBC cases with 2,212 individually matched unilateral breast cancer (UBC) controls. Participants were younger than age 55 years when diagnosed with a first invasive breast cancer between 1985 and 2008. Women were interviewed about breast cancer risk factors, including family history. A subset of women was screened for deleterious mutations in BRCA1/2, ATM, CHEK2*1100delC, and PALB2. Rate ratios (RRs) were estimated using multivariable conditional logistic regression. Cumulative absolute risks (ARs) were estimated by combining RRs from the WECARE Study and population-based SEER*Stat cancer incidence data. Results Women with any first-degree relative with breast cancer had a 10-year AR of 8.1% for CBC (95% CI, 6.7% to 9.8%). Risks also were increased if the relative was diagnosed at an age younger than 40 years (10-year AR, 13.5%; 95% CI, 8.8% to 20.8%) or with CBC (10-year AR, 14.1%; 95% CI, 9.5% to 20.7%). These risks are comparable with those seen in BRCA1/2 deleterious mutation carriers (10-year AR, 18.4%; 95% CI, 16.0% to 21.3%). In the subset of women who tested negative for deleterious mutations in BRCA1/2, ATM, CHEK2*1100delC, and PALB2, estimates were unchanged. Adjustment for known breast cancer single-nucleotide polymorphisms did not affect estimates. Conclusion Breast cancer family history confers a high CBC risk, even after excluding women with deleterious mutations. Clinicians are urged to use detailed family histories to guide treatment and future screening decisions for young women with breast cancer.

Preoperative Breast Magnetic Resonance Imaging Use by Breast Density and Family History of Breast Cancer

BACKGROUND

Use of preoperative breast magnetic resonance imaging (MRI) among women with a new breast cancer has increased over the past decade. MRI use is more frequent in younger women and those with lobular carcinoma, but associations with breast density and family history of breast cancer are unknown.

MATERIALS AND METHODS

Data for 3075 women ages >65 years with stage 0-III breast cancer who underwent breast conserving surgery or mastectomy from 2005 to 2010 in the Breast Cancer Surveillance Consortium were linked to administrative claims data to assess associations of preoperative MRI use with mammographic breast density and first-degree family history of breast cancer. Multivariable logistic regression estimated adjusted odds ratios (OR) and 95% confidence intervals (95% CI) for the association of MRI use with breast density and family history, adjusting for woman and tumor characteristics.

RESULTS

Overall, preoperative MRI use was 16.4%. The proportion of women receiving breast MRI was similar by breast density (17.6% dense, 16.9% nondense) and family history (17.1% with family history, 16.5% without family history). After adjusting for potential confounders, we found no difference in preoperative MRI use by breast density (OR = 0.95 for dense vs. nondense, 95% CI: 0.73-1.22) or family history (OR = 0.99 for family history vs. none, 95% CI: 0.73-1.32).

CONCLUSIONS

Among women aged >65 years with breast cancer, having dense breasts or a first-degree relative with breast cancer was not associated with greater preoperative MRI use. This utilization is in keeping with lack of evidence that MRI has higher yield of malignancy in these subgroups.

Interactions of Family History of Breast Cancer with Radiotherapy in Relation to the Risk of Breast Cancer Recurrence

Purpose

We examined associations between a family history of breast cancer and the risk of breast cancer recurrence in women who received or did not receive radiotherapy.

Methods

Our study included 2,440 women enrolled in the Breast Cancer Registry of Greater Cincinnati. Information on breast cancer risk factors, including detailed family history of breast cancer, characteristics of the primary tumor, treatment received, and recurrence status was collected at baseline and via updates. Associations between a family history of breast cancer and the risk of breast cancer recurrence were examined separately in women treated with and without radiotherapy using survival analysis.

Results

Over an average follow-up time of 8.78 years, we found no associations between a family history of breast cancer and the risk of breast cancer recurrence among women with a history of radiotherapy (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.75–1.23). Among women who did not receive radiotherapy, the total number of relatives with breast cancer was positively associated with the risk of breast cancer recurrence (HR, 1.21; 95% CI, 1.00–1.47). We found no interactions of radiotherapy with family history (p-interaction >0.05).

Conclusion

Radiotherapy for a primary breast cancer in women with a family history of breast cancer does not increase risk of breast cancer recurrence. If these findings are replicated in future studies, the results may translate into an important health message for breast cancer survivors with a family history of breast cancer.

Contralateral Breast Cancer Risk in Women with Ductal Carcinoma In Situ: Is it High Enough to Justify Bilateral Mastectomy?

BACKGROUND

Women with ductal carcinoma in situ (DCIS) are increasingly choosing bilateral mastectomy. We sought to quantify rates of contralateral breast cancer (CBC) and ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery (BCS) for DCIS, and to compare risk factors for CBC and IBTR.

METHODS

From 1978 to 2011, DCIS patients undergoing BCS with a contralateral breast at risk were identified from a prospectively maintained database. The association of clinicopathologic and treatment factors with CBC and IBTR were evaluated using Kaplan-Meier analysis, multivariable Cox regression, and competing risk regression (CRR).

RESULTS

Of 2759 patients identified, 151 developed CBC and 344 developed IBTR. Five- and 10-year Kaplan-Meier CBC rates were 3.2 and 6.4%. Overall, 10-year IBTR rates were 2.5-fold higher than CBC rates, and, without radiation, 4-fold higher. On CRR, 5- and 10-year rates were 2.9 and 5.8% for CBC, and 7.8 and 14.5% for IBTR. CBC risk and invasive CBC risk were not significantly associated with age, family history, presentation, nuclear grade, year of surgery, or radiation. By multivariable Cox regression, endocrine therapy was associated with lower CBC risk (hazard ratio 0.57, p = 0.03). Ten-year risk of subsequent CBC in the subset of patients who developed IBTR was similar to the cohort as a whole (8.1 vs. 6.4%).

CONCLUSIONS

CBC rates were low across all groups, including those who experienced IBTR. CBC was not associated with factors that increase IBTR risk. While factors associated with IBTR risk are important in decision making regarding management of the index DCIS, they are not an indication for contralateral prophylactic mastectomy.

Association of Common Genetic Variants With Contralateral Breast Cancer Risk in the WECARE Study

Background

Women with unilateral breast cancer (UBC) are at risk of developing a subsequent contralateral breast cancer (CBC). Common variants are associated with breast cancer risk. Whether these influence CBC risk is unknown.

Methods

Participants were breast cancer cases from the population-based Women's Environmental Cancer and Radiation Epidemiology (WECARE) Study. Sixty-seven established breast cancer risk loci were genotyped directly or by imputation in 1459 case subjects with CBC and 2126 UBC control subjects. An unweighted polygenic risk score (PRS) was created by summing the number of risk alleles for each directly genotyped single nucleotide polymorphism (SNP), or for imputed loci, the imputed dosage. A weighted PRS was calculated similarly, but where each SNP's contribution was weighted by the published per-allele log odds ratio. Unweighted and weighted polygenic risk scores and CBC risk were modeled using conditional logistic regression. Cumulative CBC risk was estimated and benchmarked using Surveillance, Epidemiology, and End Results population incidence rates.

Results

Both unweighted and weighted PRS were statistically significantly associated with CBC risk. The adjusted risk ratio of CBC in women in the upper quartile of unweighted PRS compared with the lowest quartile was 1.63 (95% confidence interval [CI] = 1.33 to 2.00). The estimated 10-year cumulative risk for women in the upper quartile of the unweighted PRS was 7.4% (95% CI = 6.0% to 9.1%). For women in the upper quartile of the weighted PRS, the risk ratio for CBC was 1.75 (95% CI = 1.41 to 2.18) compared with women in the lowest quartile. There was no statistically significant heterogeneity by age, treatment (radiation therapy dose, tamoxifen, chemotherapy), estrogen receptor status of the first primary, histology of the first primary, length of at-risk period for CBC, or breast cancer family history.

Conclusions

Common genomic variants associated with the development of first primary breast cancer are also associated with the development of CBC; the risk is strongest among those who carry more risk alleles.

Psychosocial factors associated with the uptake of contralateral prophylactic mastectomy among BRCA1/2 mutation noncarriers with newly diagnosed breast cancer

PURPOSE

Women who are newly diagnosed with breast cancer may consider contralateral prophylactic mastectomy (CPM) to reduce their future risk of cancer in their unaffected breast. Pre-surgical BRCA1/2 genetic testing can provide valuable risk information to guide this choice. However, little is understood about why BRCA1/2 mutation noncarriers, who are generally not at substantially elevated risk of contralateral disease, select CPM.

METHODS

We examined the uptake of CPM among breast cancer patients identified as BRCA1/2 mutation noncarriers (n = 92) as part of a larger prospective study of the impact of pre-surgical BRCA1/2 testing. Data obtained from self-report questionnaires and patient medical records were used to examine associations between theoretically relevant background and psychosocial factors and BRCA1/2 mutation noncarriers' decisions to undergo CPM.

RESULTS

Among BRCA1/2 mutation noncarriers, 25% (n = 23) elected to undergo CPM. Psychosocial factors including a self-reported physician recommendation for CPM, greater perceived contralateral breast cancer risk, and greater perceived benefits of CPM were all significantly associated with the uptake of CPM.

CONCLUSIONS

A sizeable minority of BRCA1/2 mutation noncarriers choose to undergo CPM after learning their mutation status through pre-surgical genetic testing. BRCA1/2 mutation noncarriers' cognitive perceptions and social influences appear to be important in shaping their decisions regarding CPM. This work highlights the importance of several psychosocial factors in influencing patients' surgical decisions. Future research is needed that examines the formation of BRCA1/2 mutation noncarriers' beliefs regarding their disease and available treatment options, and that characterizes the physician-patient communication that occurs in this complex decision-making context.

Disparities in contralateral prophylactic mastectomy use among women with early-stage breast cancer

Contralateral prophylactic mastectomy use has increased over the past decades among women with early-stage breast cancer. Racial differences in contralateral prophylactic mastectomy use are well described, but with unclear causes. This study examined contralateral prophylactic mastectomy use among black and white women and the contribution of differences in perceived risk to differences in use. We surveyed women diagnosed with early-stage unilateral breast cancer between ages 41-64 in Pennsylvania and Florida between 2007-2009 to collect data on breast cancer treatment, family history, education, income, insurance, and perceived risk. Clinical factors-age,stage at diagnosis, receptor status-were obtained from cancer registries. The relationships between patient factors and contralateral prophylactic mastectomy were assessed using logistic regression. The interaction between race and contralateral prophylactic mastectomy on the perceived risk of second breast cancers was tested using linear regression. Of 2182 study participants, 18% of whites underwent contralateral prophylactic mastectomy compared with 10% of blacks (p < 0.001). The racial difference remained after adjustment for clinical factors and family history (odds ratio = 2.32, 95% confidence interval 1.76-3.06, p < 0.001). The association between contralateral prophylactic mastectomy and a reduction in the perceived risk of second breast cancers was significantly smaller for blacks than whites. Blacks were less likely than whites to undergo contralateral prophylactic mastectomy even after adjustment for clinical factors. This racial difference in use may relate to the smaller impact of contralateral prophylactic mastectomy on the perceived risk of second breast cancers among blacks than among whites. Future research is needed to understand the overall impact of perceived risk on decisions about contralateral prophylactic mastectomy and how that may explain racial differences in use.

Long-Term Satisfaction and Body Image After Contralateral Prophylactic Mastectomy

BACKGROUND

Contralateral prophylactic mastectomy (CPM) rates have been increasing in the US, and although high levels of satisfaction with CPM have been reported, few studies have evaluated the long-term effects on body image, comparing CPM with breast-conserving surgery (BCS) and unilateral mastectomy (UM).

METHODS

We analyzed responses from a survey of women with both a personal and family history of breast cancer who were enrolled in the Sister Study (n = 1176). Among women who underwent mastectomy, we examined satisfaction with the mastectomy decision, as well as variation in the use of reconstruction and experience of complications. Five survey items, evaluated individually and as a summed total score, were used to compare body image across surgery types (BCS, UM without reconstruction, CPM without reconstruction, UM with reconstruction, and CPM with reconstruction).

RESULTS

Participants were, on average, 3.6 years post-diagnosis at the time of survey (standard deviation 1.7). The majority of women (97% of CPM, 89% of UM) were satisfied with their mastectomy decision. Reconstruction was more common after CPM than after UM (70 vs. 47%), as were complications (28 vs. 19%). Body image scores were significantly worse among women who underwent CPM than among women who underwent BCS, with the lowest scores among women who underwent CPM without reconstruction.

CONCLUSIONS

In our sample, most women were highly satisfied with their mastectomy decision, including those who elected to undergo CPM. However, body image was lower among those who underwent CPM than among those who underwent BCS. Our findings may inform decisions among women considering various courses of surgical treatment.

A model for individualized risk prediction of contralateral breast cancer

PURPOSE

Patients diagnosed with invasive breast cancer (BC) or ductal carcinoma in situ are increasingly choosing to undergo contralateral prophylactic mastectomy (CPM) to reduce their risk of contralateral BC (CBC). This is a particularly disturbing trend as a large proportion of these CPMs are believed to be medically unnecessary. Many BC patients tend to substantially overestimate their CBC risk. Thus, there is a pressing need to educate patients effectively on their CBC risk. We develop a CBC risk prediction model to aid physicians in this task.

METHODS

We used data from two sources: Breast Cancer Surveillance Consortium and Surveillance, Epidemiology, and End Results to build the model. The model building steps are similar to those used in developing the BC risk assessment tool (popularly known as Gail model) for counseling women on their BC risk. Our model, named CBCRisk, is exclusively designed for counseling women diagnosed with unilateral BC on the risk of developing CBC.

RESULTS

We identified eight factors to be significantly associated with CBC-age at first BC diagnosis, anti-estrogen therapy, family history of BC, high-risk pre-neoplasia status, estrogen receptor status, breast density, type of first BC, and age at first birth. Combining the relative risk estimates with the relevant hazard rates, CBCRisk projects absolute risk of developing CBC over a given period.

CONCLUSIONS

By providing individualized CBC risk estimates, CBCRisk may help in counseling of BC patients. In turn, this may potentially help alleviate the rate of medically unnecessary CPMs.

Society of Surgical Oncology Breast Disease Working Group Statement on Prophylactic (Risk-Reducing) Mastectomy

Over the past several years, there has been an increasing rate of bilateral prophylactic mastectomy (BPM) and contralateral prophylactic mastectomy (CPM) surgeries. Since publication of the 2007 SSO position statement on the use of risk-reducing mastectomy, there have been significant advances in the understanding of breast cancer biology and treatment. The purpose of this manuscript is to review the current literature as a resource to facilitate a shared and informed decision-making process regarding the use of risk-reducing mastectomy.