Prevalence of BRCA1 and BRCA2 mutations in women with breast carcinoma In Situ and referred for genetic testing

Germline Genetic Testing Among Women ≤ 45 Years of Age with Ductal Carcinoma In Situ Versus Invasive Breast Cancer in a Large Integrated Health Care System

BACKGROUND

We compared the results of hereditary cancer multigene panel testing among patients ≤ 45 years of age diagnosed with ductal carcinoma in situ (DCIS) versus invasive breast cancer (IBC) in a large integrated health care system.

METHODS

A retrospective cohort study of hereditary cancer gene testing among women ≤ 45 years of age diagnosed with DCIS or IBC at Kaiser Permanente Northern California between September 2019 and August 2020 was performed. During the study period, institutional guidelines recommended the above population be referred to genetic counselors for pretesting counseling and testing.

RESULTS

A total of 61 DCIS and 485 IBC patients were identified. Genetic counselors met with 95% of both groups, and 86.4% of DCIS patients and 93.9% of IBC patients (p = 0.0339) underwent gene testing. Testing differed by race/ethnicity (p = 0.0372). Among those tested, 11.76% (n = 6) of DCIS patients and 16.71% (n = 72) of IBC patients had a pathogenic variant (PV) or likely pathogenic variant (LPV) based on the 36-gene panel (p = 0.3650). Similar trends were seen in 13 breast cancer (BC)-related genes (p = 0.0553). Family history of cancer was significantly associated with both BC-related and non-BC-related PVs in IBC, but not DCIS.

CONCLUSION

In our study, 95% of patients were seen by a genetic counselor when age was used as an eligibility criterion for referral. While larger studies are needed to further compare the prevalence of PVs/LPVs among DCIS and IBC patients, our data suggest that even in younger patients, the prevalence of PVs/LPVs in BC-related genes is lower in DCIS patients.

Differential involvement of germline pathogenic variants in breast cancer genes between DCIS and low-grade invasive cancers

PURPOSE

To investigate frequency of germline pathogenic variants (PVs) in women with ductal carcinoma in situ (DCIS) and grade 1 invasive breast cancer (G1BC).

METHODS

We undertook BRCA1/2 analysis in 311 women with DCIS and 392 with G1BC and extended panel testing (non-BRCA1/2) in 176/311 with DCIS and 156/392 with G1BC. We investigated PV detection by age at diagnosis, Manchester Score (MS), DCIS grade and receptor status.

RESULTS

30/311 (9.6%) with DCIS and 16/392 with G1BC (4.1%) had a BRCA1/2 PV (p=0.003), and 24/176-(13.6%) and 7/156-(4.5%), respectively, a non-BRCA1/2 PV (p=0.004). Increasing MS was associated with increased likelihood of BRCA1/2 PV in both DCIS and G1BC, although the 10% threshold was not predictive for G1GB. 13/32 (40.6%) DCIS and 0/17 with G1BC <40 years had a non-BRCA1/2 PV (p<0.001). 0/16 DCIS G1 had a PV. For G2 and G3 DCIS, PV rates were 10/98 (BRCA1/2) and 9/90 (non-BRCA1/2), and 8/47 (BRCA1/2) and 8/45 (non-BRCA1/2), respectively. 6/9 BRCA1 and 3/26 BRCA2-associated DCIS were oestrogen receptor negative-(p=0.003). G1BC population testing showed no increased PV rate (OR=1.16, 95% CI 0.28 to 4.80).

CONCLUSION

DCIS is more likely to be associated with both BRCA1/2 and non-BRCA1/2 PVs than G1BC. Extended panel testing ought to be offered in young-onset DCIS where PV detection rates are highest.

Clinicopathological and imaging features of ductal carcinoma in situ in BRCA1/2 mutation carriers

BACKGROUND

BRCA1/2-associated invasive breast cancer has been extensively studied. However, there are few reports of ductal carcinoma in situ (DCIS).

OBJECTIVE

This study aimed to investigate the clinicopathological and imaging findings of DCIS in patients with BRCA1/2 mutations.

METHODS

This was a single-institution, retrospective study. We identified patients diagnosed with DCIS with BRCA mutations between September 2003 and December 2020. Clinicopathological data and mammography (MG), magnetic resonance imaging (MRI), and ultrasound (US) findings were reviewed.

RESULTS

We identified 30 cancers in 28 patients; 7 (25.0%) patients had BRCA1 mutations, and 21 (75.0%) had BRCA2 mutations. The median patient age was 42 years. Screening was the most common reason for the detection of DCIS (50.0%), followed by occult cancer diagnosed by pathological examination after risk-reducing mastectomy (26.7%). The nuclear grade was most often 1 (46.7%), and 93.3% were estrogen and/or progesterone receptor positive. The detection rates of MG, MRI, and US were 64.3%, 72.0%, and 64.0%, respectively. The most common imaging findings were calcification (100%) on MG, non-mass enhancement (88.9%) on MRI, and hypoechoic area (75.0%) on US.

CONCLUSION

BRCA-associated DCIS was more strongly associated with BRCA2, and imaging features were similar to those of sporadic DCIS. Our results are helpful in informing surveillance strategies based on genotypes in women with BRCA mutations.

Identifying recurrences and metastasis after ductal carcinoma in situ (DCIS) of the breast

Ductal carcinoma in situ (DCIS) of the breast is a non-invasive tumour that has the potential to progress to invasive ductal carcinoma (IDC). Thus, it represents a treatment dilemma: alone it does not present a risk to life, however, left untreated it may progress to a life-threatening condition. Current clinico-pathological features cannot accurately predict which patients with DCIS have invasive potential, and therefore clinicians are unable to quantify the risk of progression for an individual patient. This leads to many women being over-treated, while others may not receive sufficient treatment to prevent invasive recurrence. A better understanding of the molecular features of DCIS, both tumour-intrinsic and the microenvironment, could offer the ability to better predict which women need aggressive treatment, and which can avoid therapies carrying significant side-effects and such as radiotherapy. In this review, we summarise the current knowledge of DCIS, and consider future research directions.

The Screen Project: Guided Direct-To-Consumer Genetic Testing for Breast Cancer Susceptibility in Canada

There is limited information of the outcomes of direct-to-consumer testing for BRCA1 and BRCA2 mutations. The Screen Project was initiated in 2017 to offer BRCA1 and BRCA2 genetic screening to all Canadians over the age of 18 who wish to know their mutation status. Patients enrolled in the study from 2017 to 2019 and were followed for one year after the receipt of a genetic test result. Study subjects registered online and were sent a saliva sample kit, which was shipped to the reference laboratory. Pre-test genetic counselling and counselling for mutation-negative subjects was optional and at the individual's discretion. There were 1269 tested individuals between March 2017 and January 2019. A total of 1157 (93%) were women and 87 (7%) were men. Sixty-six percent had a first- or second-degree relative with breast or ovarian cancer. Of the 1269 tested individuals, 30 (2.4%) had a pathogenic mutation in BRCA1 or BRCA2 (20 women and 10 men). Seventy-five percent of the female mutation carriers underwent a bilateral mastectomy and/or salpingo-oophorectomy within a year of receiving a positive result. Genetic counselling was available at no cost to all participants but was requested by only 5% of the non-carriers. The study subjects expressed a high degree of satisfaction with the process.

Risk of invasive breast cancer in relatives of patients with breast carcinoma in situ: a prospective cohort study

BACKGROUND

Wide implementation of mammography screening has resulted in increased numbers of women diagnosed with breast carcinoma in situ. We aimed to determine the risk of invasive breast cancer in relatives of patients with breast carcinoma in situ in comparison to the risk in relatives of patients with invasive breast cancer.

METHODS

We analyzed the occurrence of cancer in a nationwide cohort including all 5,099,172 Swedish women born after 1931 with at least one known first-degree relative. This was a record linkage study of Swedish family cancer datasets, including cancer registry data collected from January 1, 1958, to December 31, 2015. We calculated standardized incidence ratios (SIRs) and 10-year cumulative risk of breast cancer diagnosis for women with a family history of in situ and invasive breast cancer.

RESULTS

Having one first-degree relative with breast carcinoma in situ was associated with 50% increased risk of invasive breast cancer (SIR = 1.5, 95% CI 1.4-1.7) when compared to those who had no family history of invasive breast cancer or breast carcinoma in situ in either first- or second-degree relatives. Similarly, having one first-degree relative with invasive breast cancer was associated with 70% (1.7, 1.7-1.8) increased risk. The 10-year cumulative risk for women at age 50 with a relative with breast carcinoma in situ was 3.5% (2.9-3.9%) and was not significantly different from 3.7% (3.6-3.8%) risk for 50-year-old women with a relative with invasive breast cancer (95% confidence intervals overlapped).

CONCLUSIONS

The risk of invasive breast cancer for women with a family history of breast carcinoma in situ was comparable to that for women with a family history of invasive breast cancer. Therefore, family history of breast carcinoma in situ should not be overlooked in recommendations for breast cancer prevention for women with a family history of breast cancer.

Frequency of pathogenic germline variants in BRCA1, BRCA2, PALB2, CHEK2 and TP53 in ductal carcinoma in situ diagnosed in women under the age of 50 years

INTRODUCTION

Ductal carcinoma in situ (DCIS) is a non-obligate precursor of invasive ductal breast cancer, and approximately 20% of screen-detected tumours are pure DCIS. Most risk factors for breast cancer have similar associations with DCIS and IDC; however, there is limited data on the prevalence of the known high and moderate penetrance breast cancer predisposition genes in DCIS and which women with DCIS should be referred for genetic screening. The aim of this study was to assess the frequency of germline variants in BRCA2, BRCA1, CHEK2, PALB2 and TP53 in DCIS in women aged less than 50 years of age.

METHODS

After DNA extraction from the peripheral blood, Access Array technology (Fluidigm) was used to amplify all exons of these five known breast cancer predisposition genes using a custom made targeted sequencing panel in 655 cases of pure DCIS presenting in women under the age of 50 years together with 1611 controls.

RESULTS

Case-control analysis revealed an excess of pathogenic variants in BRCA2 (OR = 27.96, 95%CI 6.56-119.26, P = 2.0 × 10^-10) and CHEK2 (OR = 8.04, 95%CI 2.93-22.05, P = 9.0 × 10^-6), with weaker associations with PALB2 (P = 0.003), BRCA1 (P = 0.007) and TP53 (P = 0.02). For oestrogen receptor (ER)-positive DCIS the frequency of pathogenic variants was 9% under the age of 50 (14% with a family history of breast cancer) and 29% under the age of 40 (42% with a family history of breast cancer). For ER-negative DCIS, the frequency was 9% (16% with a family history of breast cancer) and 8% (11% with a family history of breast cancer) under the ages of 50 and 40, respectively.

CONCLUSIONS

This study has shown that breast tumourigenesis in women with pathogenic variants in BRCA2, CHEK2, PALB2, BRCA1 and TP53 can involve a DCIS precursor stage and that the focus of genetic testing in DCIS should be on women under the age of 40 with ER-positive DCIS.

BRCA1/BRCA2 mutations in Japanese women with ductal carcinoma in situ

Background

Ductal carcinoma in situ (DCIS) is considered a component of the clinical spectrum of breast cancer even in those with BRCA1/2 mutation. The aim of this study was to report the feature of DCIS raised in Japanese women with BRCA1/2 mutations.

Methods

A total of 325 Japanese women with breast cancer (BC) (with or without invasive cancer) were referred for genetic counseling and underwent genetic testing for mutations in the BRCA1 and BRCA2 genes in Showa University Hospital between December 2011 and August 2016. And 49 of them who were pathologically diagnosed as DCIS were included in this study. Logistic regression models were fit to determine the associations between potential predictive factors and BRCA status. A Cox proportional hazards model is used to predictive value of parameters for Ipsilateral breast tumor recurrence (IBTR) and contralateral breast tumor recurrence (CBTR).

Results

(a) Of 325 patients (with or without invasive cancer), 19.1% (62/325) tested positive for BRCA1/BRCA2 mutations. And 18.4% (9/49) was positive for BRCA1/BRCA2 mutations in DCIS, compared with 19.2% (53/276) in IDC (p = 1.000). Among BRCA mutations, 14.5% (9/62) had DCIS compared with nonmutations (15.2%, 40/263). Incidence of DCIS was 3.0% (1/33) of BRCA1 mutations and 27.5% (8/29) of BRCA2 mutation (p = 0.009). (b) Median age of diagnosis in BRCA mutation carriers was 39 years, compared with 46 years in noncarriers. Age, Family history (FH) of BC, FH of first or second BC and total number of relatives with BC diagnosis (DX) has significant difference between BRCA mutation carriers and noncarriers in univariate analysis. In a multivariate logistic model, total relatives with BC DX ≥ 2 (odds ratio [OR], 5.128; 95% confidence interval [CI], 1.266–20.763; p = 0.022), age at diagnosis ≤35 years (OR 0.149, 95% CI 0.023–0.954, p = 0.045) and ER+/HER2+ status (OR 5.034, 95% CI 1.092–23.210, p = 0.038) remained as independent significant predictors for BRCA mutation. Ki67 index (cut off by 14% or 30%) did not differ between BRCA mutation carriers and noncarriers (p = 0.459 and p = 0.651). (c) There was a significant difference in ER‐positive tumors among BRCA2 carriers and noncarriers (p = 0.042). Subgroup analysis showed BRCA2 carriers tend to be of higher grade (Grade 2 and 3), more frequently ER+/PR+ (p = 0.041) and lower proliferation (Ki67 index) than noncarriers, whereas differences in nuclear grade and ki67 index were not found significantly in our study. (d) BRCA mutation was not associated with an increased risk of IBTR and CBTR.

Conclusion

DCIS is equally as prevalent in patients who were BRCA mutation carriers as in high familial‐risk women who were noncarriers, but occurs at earlier age. BRCA2 carriers have higher incidence in DCIS than that of BRCA1 carriers, and tend to be higher grade and more frequently ER positive and lower proliferation. Total relatives with BC DX ≥2, age at diagnosis ≤35 years and ER+/HER2+ might be independent predictors for BRCA mutation in Japanese women with DCIS and patients of these risk factors should be recommended to receive genetic counseling and BRCA testing.

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.

Addressing health disparities in Hispanic breast cancer: accurate and inexpensive sequencing of BRCA1 and BRCA2

BACKGROUND

Germline mutations in the BRCA1 and BRCA2 genes account for 20-25 % of inherited breast cancers and about 10 % of all breast cancer cases. Detection of BRCA mutation carriers can lead to therapeutic interventions such as mastectomy, oophorectomy, hormonal prevention therapy, improved screening, and targeted therapies such as PARP-inhibition. We estimate that African Americans and Hispanics are 4-5 times less likely to receive BRCA screening, despite having similar mutation frequencies as non-Jewish Caucasians, who have higher breast cancer mortality. To begin addressing this health disparity, we initiated a nationwide trial of BRCA testing of Latin American women with breast cancer. Patients were recruited through community organizations, clinics, public events, and by mail and Internet. Subjects completed the consent process and questionnaire, and provided a saliva sample by mail or in person. DNA from 120 subjects was used to sequence the entirety of BRCA1 and BRCA2 coding regions and splice sites, and validate pathogenic mutations, with a total material cost of $85/subject. Subjects ranged in age from 23 to 81 years (mean age, 51 years), 6 % had bilateral disease, 57 % were ER/PR+, 23 % HER2+, and 17 % had triple-negative disease.

RESULTS

A total of seven different predicted deleterious mutations were identified, one newly described and the rest rare. In addition, four variants of unknown effect were found.

CONCLUSIONS

Application of this strategy on a larger scale could lead to improved cancer care of minority and underserved populations.

A Systematic Comparison of Traditional and Multigene Panel Testing for Hereditary Breast and Ovarian Cancer Genes in More Than 1000 Patients

Gene panels for hereditary breast and ovarian cancer risk assessment are gaining acceptance, even though the clinical utility of these panels is not yet fully defined. Technical questions remain, however, about the performance and clinical interpretation of gene panels in comparison with traditional tests. We tested 1105 individuals using a 29-gene next-generation sequencing panel and observed 100% analytical concordance with traditional and reference data on >750 comparable variants. These 750 variants included technically challenging classes of sequence and copy number variation that together represent a significant fraction (13.4%) of the pathogenic variants observed. For BRCA1 and BRCA2, we also compared variant interpretations in traditional reports to those produced using only non-proprietary resources and following criteria based on recent (2015) guidelines. We observed 99.8% net report concordance, albeit with a slightly higher variant of uncertain significance rate. In 4.5% of BRCA-negative cases, we uncovered pathogenic variants in other genes, which appear clinically relevant. Previously unseen variants requiring interpretation accumulated rapidly, even after 1000 individuals had been tested. We conclude that next-generation sequencing panel testing can provide results highly comparable to traditional testing and can uncover potentially actionable findings that may be otherwise missed. Challenges remain for the broad adoption of panel tests, some of which will be addressed by the accumulation of large public databases of annotated clinical variants.

Association of family risk and lifestyle/comorbidities in ovarian cancer patients

Summary Objectives: to analyze factors that might indicate familial predisposition for ovarian cancer in patients diagnosed with this disease. Methods: in a prospective single center cohort study at the Institute of Cancer of the State of São Paulo (ICESP), 51 women diagnosed with ovarian cancer were included. Familial predisposition for ovarian cancer was defined as having a higher than 10% chance of having a BRCA1/2 mutation according to the Manchester scoring system, a validated method to assess the likelihood of mutation detection. Each patient was interviewed with a standardized questionnaire on established risk factors for ovarian cancer and other factors that might influence the risk to develop ovarian cancer. Logistic regression analyses were performed to estimate the impact of the evaluated factors on the likelihood of mutation detection, by calculating odds ratios and 95% confidence intervals. Results: seventeen out of 51 patients had a family history of breast and/or ovarian cancer, four patients had a history of breast or endometrial cancer, 11 were diagnosed before the age of 50, and 12 presented a risk of familial predisposition to ovarian cancer higher than 10%. Patients with comorbidities, such as hypertension, diabetes, hormonal disorders, dyslipidemia and psychiatric conditions, presented a lower chance of having a familial predisposition for ovarian cancer (OR: 0.22; 95% CI: 0.06-0.88; p=0.03). Conclusion: in this study, having comorbidities was associated with a lower risk of having a familial predisposition for ovarian cancer. Other factors associated with the risk of ovarian cancer did not have an impact on this predisposition.

[Risk-adapted surveillance: focus on familial breast and ovarian cancer]

Breast cancer surveillance programs for the general population are not adequate for the small number of women with hereditary breast and ovarian cancer syndrome. Breast cancer screening for women in Germany starts at the age of 50 years, but nearly half of all women with familial risk are already diagnosed with breast cancer at that time. Moreover, mammography alone is not suitable for an early diagnosis of breast cancer in young women from high-risk families. Their typical dense breast tissue causes a high rate of false-negative cases. Therefore, national and international prospective clinical trials were initiated to offer a multimodal breast cancer surveillance program including magnetic resonance tomography for the breast and semi-annual screening intervals to women with BRCA1/2 mutations and those from high-risk families who tested negative for BRCA1/2 mutations. This program will currently be evaluated by the 15 centers of the German Consortium for Hereditary Breast and Ovarian Cancer.

Links between obesity, diabetes and ethnic disparities in breast cancer among Hispanic populations

Breast cancer is the most prevalent malignancy in women worldwide and is a growing concern due to rising incidence and ongoing ethnic disparities in both incidence and mortality. A number of factors likely contribute to these trends including rising rates of obesity and diabetes across the globe and differences in genetic predisposition. Here, we emphasize Hispanic populations and summarize what is currently known about obesity, diabetes and individual genetic predisposition as they relate to ethnic disparities in breast cancer incidence and mortality. In addition, we discuss potential contributions to breast cancer aetiology from molecular mechanisms associated with obesity and diabetes including dyslipidemia, hyperglycaemia, hyperinsulinaemia, endocrine dysfunction and inflammation. We propose that unique differences in diet and lifestyle coupled with individual genetic predisposition and endocrine/immune dysfunction explain most of the ethnic disparities seen in breast cancer incidence and mortality.

Ductal carcinoma in situ: how should we treat it?

SUMMARY The observed incidence of ductal carcinoma in situ (DCIS) has increased because of the increasing use of sensitive imaging modalities. While the clinical course of DCIS is quite variable, it is considered a precursor lesion to invasive breast cancer. The current focus of DCIS treatment is on the prevention of progression to invasive disease. However, at present, validated diagnostic tests to predict progression accurately are lacking. Additionally, important clinical questions arise during DCIS management. For example, optimal margins of excision or axillary lymph node sampling have not been addressed in randomized clinical trials. May whole-breast radiation after lumpectomy be omitted in selected patients? What is the role of adjuvant tamoxifen if it does not impact overall survival rates? This review aims to describe the natural history of DCIS and highlights the current therapeutic options and challenges in patient management.

Predictive factors for BRCA1/BRCA2 mutations in women with ductal carcinoma in situ

BACKGROUND

It is unclear whether women with ductal carcinoma in situ (DCIS), like their counterparts with invasive breast cancer, warrant genetic risk assessment and testing on the basis of high-risk variables. The authors of this report identified predictive factors for mutations in the breast cancer-susceptibility genes BRCA1 and BRCA2 in women who were diagnosed with DCIS.

METHODS

One hundred eighteen women with DCIS who were referred for genetic counseling and underwent genetic testing for BRCA1/BRCA2 mutations between 2003 and 2010 were included in the study. Logistic regression models were fit to determine the associations between potential predictive factors and BRCA status.

RESULTS

Of 118 high-risk women with DCIS, 27% (n = 32) tested positive for BRCA1/BRCA2 mutations. Of those, 10% (n = 12) and 17% (n = 20) had BRCA1 and BRCA2 mutations, respectively. Age, race, and tumor characteristics did not differ between BRCA noncarriers and carriers. In a multivariate logistic model, ≥2 relatives with ovarian cancer (OC) (odds ratio [OR], 8.81; 95% confidence interval [CI], 1.38-56.29; P = .034), and a score ≥10% according to the BRCAPRO mathematical model for calculating the probability that a particular family member carries a germline BRCA mutation (OR, 6.37; 95% CI, 2.23-18.22; P = .0005) remained as independent significant predictors for a BRCA mutation. Fifty-seven percent of mutation carriers but only 25% of noncarriers underwent prophylactic mastectomy(P = .0037). This difference remained significant for patients aged ≤40 years (P = .025).

CONCLUSIONS

Women who had DCIS and a family history of OC or who had BRCAPRO scores ≥10% had a high rate of BRCA positivity regardless of age at diagnosis. These findings suggest that high-risk patients with DCIS are appropriate candidates for genetic testing for BRCA mutations in the presence of predictive factors even if they do not have invasive breast cancer.