Genetic testing women with newly diagnosed breast cancer: What criteria are the most predictive of a positive test?

BACKGROUND: Knowledge of pathogenic variants in cancer-predisposing genes is important when making breast cancer treatment decisions, but genetic testing is not universal and criteria must be met to qualify for genetic testing. The objective of this study was to evaluate the pathogenic variant yield for nine cancer predisposition genes by testing criteria, singly and in combination. METHODS: Women diagnosed with breast cancer between June 2013 and May 2018 were recruited from four centers in Toronto, Canada. Participants completed a demographics and family history questionnaire and clinical characteristics were collected from medical charts. Genetic testing was done for BRCA1, BRCA2, PALB2, ATM, CHEK2, BRIP1, RAD51D, RECQL, and TP53. Pathogenic variant frequencies were calculated according to five criteria (age ≤ 50, triple-negative breast cancer, family history, bilateral breast cancer, or Jewish ethnicity). RESULTS: Of the 1006 women studied, 100 women (9.9%) were found to have a pathogenic variant in one of the nine genes tested. The highest prevalence of pathogenic variants was found in women with triple-negative breast cancer (23%). Of the 100 pathogenic variants detected, 78 were detected in women diagnosed at age 50 or less. A total of 96% of the mutations were identified with three criteria (age of diagnosis, family history, and triple-negative status). CONCLUSIONS: Genetic testing criteria for women with breast cancer should include women with triple-negative breast cancer, regardless of age. All women aged 50 years or below at time of breast cancer diagnosis should be offered genetic testing.

Impact of rapid genetic testing for BRCA1 and BRCA2 at time of breast cancer diagnosis on psychosocial functioning.

PURPOSE: Many women are being offered rapid genetic testing (RGT) for cancer predisposition genes, at the time of breast cancer diagnosis prior to surgery. The goal of this study was to determine if psychosocial functioning was affected in women receiving RGT for BRCA1 and BRCA2 at the time of breast cancer diagnosis. METHODS: Participants were women with invasive breast cancer diagnosed between 2013 and 2018, at four centres in Toronto, Canada. Eligible women were referred into the study by their surgeon at the time of diagnosis. Participants received pre-test genetic counselling and were offered RGT for BRCA1 and BRCA2. Standardized questionnaires (Impact of Event Scale and Hospital Anxiety and Depression Scale) were completed before genetic counselling, and follow-up questionnaires at one-week and one-year post-genetic test result disclosure (higher scores indicate higher symptoms). RESULTS: 1007 women had RGT; 60 women (6.0%) were found to have a BRCA1 or BRCA2 mutation, 80 women (7.9%) had a VUS, and 867 (86.1%) had a negative test result. At one-week post-testing, there were no differences in distress (p = 0.32), anxiety (p = 0.14), or depression (p = 0.42) between women with a BRCA1/2 mutation and those with a negative result. At one year, there were no differences in distress (p = 0.75) or anxiety (p = 0.13) between women with a BRCA1 or BRCA/2 mutation and those with a negative result. However, women with a BRCA1 or BRCA2 mutation had significantly lower depression scores compared to women with a negative result (p = 0.03). CONCLUSION: For women who have RGT for BRCA1 and BRCA2 at the time of breast cancer diagnosis, identifying a BRCA1 or BRCA2 mutation does not impair psychosocial functioning in the short or long term.

Frequency of Contralateral Prophylactic Mastectomy in Breast Cancer Patients with a Negative BRCA1 and BRCA2 Rapid Genetic Test Result.

BACKGROUND: There is an increasing desire for contralateral prophylactic mastectomy (CPM) among patients with unilateral breast cancer. It is unknown if risk assessment and genetic testing at the time of diagnosis will aid women in their surgical choice. We report on the uptake and predictors of CPM in women receiving a negative genetic test result for BRCA1 and BRCA2 mutations before surgery. METHODS: Women diagnosed with breast cancer between June 2013 and May 2018 were recruited from four academic health sciences centers in Toronto, Canada. Genetic counseling (risk assessment) and genetic testing was performed prior to surgery. Women were asked about their surgical preference before surgery. At 1 year post-surgery we asked what surgery was completed. This study reports on women who received a negative BRCA1/BRCA2 result. RESULTS: A total of 766 women with a mean age of 46 years (range 21-82) were included in the analysis. Before genetic counseling and testing, 37% of the women were undecided or leaning towards CPM; however, after receiving a negative BRCA test, 15% of the women opted for CPM. Thirty percent of women whose mother died of breast cancer elected for CPM, compared with 15% of women whose mother did not die of breast cancer (p = 0.03). CONCLUSIONS: Women receiving a risk assessment and negative BRCA1/BRCA2 genetic test result before surgery use this information to guide their surgical decision. Uptake of CPM for women who were planning on CPM before genetic testing decreases after receiving a negative BRCA1/BRCA2 genetic test result.

Rapid Genetic Testing for BRCA1 and BRCA2 Mutations at the Time of Breast Cancer Diagnosis: An Observational Study.

BACKGROUND: This study aimed to evaluate the impact of rapid genetic testing (RGT) for BRCA1 and BRCA2 at the time of breast cancer diagnosis on treatment choices. Bilateral mastectomy for the treatment of breast cancer in women with a BRCA1 or BRCA2 mutation offers a reduction in the risk of contralateral breast cancer. It is unclear whether offering RGT at the time of breast cancer diagnosis has an impact on women's surgical decision-making. METHODS: Women with breast cancer diagnosed between June 2013 and May 2018 were recruited from four academic health sciences centers in Toronto, Canada. The participants completed a questionnaire before genetic testing, then one week and one year after disclosure of the genetic test result. Before surgery, RGT was performed. Diagnostic, pathologic, and treatment data were compared between those with and those without a BRCA mutation. RESULTS: The study enrolled 1007 women who consented to RGT. The mean age of the participants was 46.3 years, and the median time to result disclosure was 10 days. A BRCA mutation was found in 6% of the women. The women with a BRCA mutation were significantly more likely to elect for bilateral mastectomy than the women without a BRCA mutation (p < 0.0001). Of the BRCA-positive patients, 95.7% reported that they used their genetic test result to make a surgical decision. CONCLUSIONS: The women provided with RGT at the time of breast cancer diagnosis use the genetic information to make treatment decisions, and the majority of those identified with a BRCA mutation elect for a bilateral mastectomy.

The relationship between the predicted risk of death and psychosocial functioning among women with early-stage breast cancer.

PURPOSE: Many women with early-onset breast cancer experience adverse psychological sequelae which impact on their quality of life. We sought to correlate levels of anxiety and cancer-related distress in women with breast cancer shortly after surgery and one year after treatment with the estimated risk of death. METHODS: We studied 596 women with Stage I to III breast cancer. For each woman we estimated the five-year risk of death based on SEER data from 2010 to 2019. For each woman we measured anxiety and cancer-related distress levels shortly after surgery and one year later. RESULTS: The mean estimated five-year survival was 95%. At one week post-surgery, 59% of women had a clinically significant level of anxiety and 74% had a clinically significant level of cancer-related distress. There was no correlation between the objective risk of death and the level of anxiety or distress, at one week or at one year. CONCLUSIONS: Many women diagnosed with early-stage breast cancers experience significant levels of anxiety and distress. The emotional response to a breast cancer diagnosis is not related to the risk of death per se and other factors should be explored.

Revisiting breast cancer patients who previously tested negative for BRCA mutations using a 12-gene panel.

PURPOSE: BRCA mutations contribute to about 20% of all hereditary breast cancers. With full-genome sequencing as the emerging standard for genetic testing, other breast cancer susceptibility genes have been identified and may collectively contribute to up to 30% of all hereditary breast cancers. We re-assessed women who had previously tested negative for a BRCA mutation when outdated techniques were used, and discuss the implications of identifying a mutation several years after initial genetic testing. METHODS: We evaluated the prevalence of mutations in 12 breast cancer susceptibility genes (including BRCA1 and BRCA2) in 190 breast cancer patients with a strong family history of breast cancer. These women had previously tested negative for mutations in the large coding exons of BRCA1 and BRCA2 using the protein truncation test (PTT) between the years of 1996 and 2013. RESULTS: We identified pathogenic mutations in 17 of 190 (9%) women. Six mutations were detected in BRCA1 (n = 2) and BRCA2 (n = 4). Eleven mutations were found in other breast cancer susceptibility genes including CHEK2 (n = 5), PALB2 (n = 2), BLM (n = 2), ATM (n = 1) and TP53 (n = 1). CONCLUSION: Among 190 breast cancer patients with a family history of the disease, and who previously received a negative result for BRCA mutations using the PTT, 17 (9%) women were found to carry a high-risk pathogenic mutation in a breast cancer susceptibility gene. Six of these women were BRCA mutation carriers who were missed previously. These findings support the rationale for updated genetic testing in patients who tested BRCA mutation negative using outdated techniques.

Effect of decision aid for breast cancer prevention on decisional conflict in women with a BRCA1 or BRCA2 mutation: a multisite, randomized, controlled trial.

PURPOSE: Women with a BRCA1 or BRCA2 mutation are at high risk for breast cancer and must make important decisions about breast cancer prevention and screening. In the current study, we report a multisite, randomized, controlled trial evaluating the effectiveness of a decision aid for breast cancer prevention in women with a BRCA mutation with no previous diagnosis of cancer. METHODS: Within 1 month of receiving a positive BRCA result, women were randomized to receive either usual care (control group) or decision aid (intervention group). Participants were followed at 3, 6, and 12 months; were asked about preventive measures; and completed standardized questionnaires assessing decision making and psychosocial functioning. RESULTS: One hundred fifty women were randomized. Mean cancer-related distress scores were significantly lower in the intervention group compared with the control group at 6 months (P = 0.01) and at 12 months postrandomization (P = 0.05). Decisional conflict scores declined over time for both groups and at no time were there statistical differences between the two groups. CONCLUSION: The decision aid for breast cancer prevention in women with a BRCA1 or BRCA2 mutation is effective in significantly decreasing cancer-related distress within the year following receipt of positive genetic test results.Genet Med 19 3, 330-336.

Relationship between Caffeine and Levels of DNA Repair and Oxidative Stress in Women with and without a BRCA1 Mutation.

BACKGROUND: Coffee consumption has been associated with a reduction in breast cancer risk among women with a BRCA1 mutation. The objective of this study was to evaluate whether major contributors of caffeine intake are associated with a reduction in DNA damage and/or oxidative stress in women with and without a BRCA1 mutation. METHODS: Coffee, tea, soda and total caffeine consumption was collected by a dietary history questionnaire, and DNA repair capacity in lymphocytes was assessed by the comet assay (tail moments), micronucleus test (per 1,000 binucleated cells) and analysis of γ-H2AX staining (nuclear foci). The thiobarbituric acid-malondialdehyde and DTNB assays were used to estimate serum lipid peroxidation (µmol/l) and protein oxidation (µmol/l), respectively. RESULTS: Among all women, high levels of caffeine and caffeinated coffee intake were associated with significantly lower levels of micronuclei (138.50 vs. 97.67, p = 0.04, and 138.12 vs. 97.70, p = 0.04). There was no significant relationship between caffeine, coffee, tea and soda intake and the other markers of DNA repair capacity and oxidative stress among all women and in analyses stratified by BRCA1 mutation status. CONCLUSION: The chemopreventive effects of coffee and/or caffeine may be associated with improved capacity to efficiently repair DNA damage.

The impact of pregnancy on breast cancer survival in women who carry a BRCA1 or BRCA2 mutation.

Physicians are often approached by young women with a BRCA mutation and a recent history of breast cancer who wish to have a baby. They wish to know if pregnancy impacts upon their future risks of cancer recurrence and survival. To date, there is little information on the survival experience of women who carry a mutation in one of the BRCA genes and who become pregnant. From an international multi-center cohort study of 12,084 women with a BRCA1 or BRCA2 mutation, we identified 128 case subjects who were diagnosed with breast cancer while pregnant or who became pregnant after a diagnosis of breast cancer. These women were age-matched to 269 mutation carriers with breast cancer who did not become pregnant (controls). Subjects were followed from the date of breast cancer diagnosis until the date of last follow-up or death from breast cancer. The Kaplan-Meier method was used to estimate 15-year survival rates. The hazard ratio for survival associated with pregnancy was calculated using a left-truncated Cox proportional hazard model, adjusting for other prognostic factors. Among women who were diagnosed with breast cancer when pregnant or who became pregnant thereafter, the 15-year survival rate was 91.5 %, compared to a survival of 88.6 % for women who did not become pregnant (adjusted hazard ratio = 0.76; 95 % CI 0.31-1.91; p = 0.56). Pregnancy concurrent with or after a diagnosis of breast cancer does not appear to adversely affect survival among BRCA1/2 mutation carriers.

Breastfeeding and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.

INTRODUCTION: Breastfeeding has been inversely related to breast cancer risk in the general population. Clarifying the role of breastfeeding among women with a BRCA1 or BRCA2 mutation may be helpful for risk assessment and for recommendations regarding prevention. We present an updated analysis of breastfeeding and risk of breast cancer using a large matched sample of BRCA mutation carriers. METHODS: We conducted a case-control study of 1,665 pairs of women with a deleterious mutation in either BRCA1 (n = 1,243 pairs) or BRCA2 (n = 422 pairs). Breast cancer cases and unaffected controls were matched on year of birth, mutation status, country of residence and parity. Information about reproductive factors, including breastfeeding for each live birth, was collected from a routinely administered questionnaire. Conditional logistic regression was used to estimate the association between ever having breastfed, as well as total duration of breastfeeding, and the risk of breast cancer. RESULTS: Among BRCA1 mutation carriers, breastfeeding for at least one year was associated with a 32% reduction in risk (OR = 0.68; 95% CI 0.52 to 0.91; P = 0.008); breastfeeding for two or more years conferred a greater reduction in risk (OR = 0.51; 95% CI 0.35 to 0.74). Among BRCA2 mutation carriers, there was no significant association between breastfeeding for at least one year and breast cancer risk (OR = 0.83; 95% CI 0.53 to 1.31; P = 0.43). CONCLUSIONS: These data extend our previous findings that breastfeeding protects against BRCA1-, but not BRCA2-associated breast cancer. BRCA mutation carriers should be advised of the benefit of breastfeeding in terms of reducing breast cancer risk.

Long-term follow-up of Jewish women with a BRCA1 and BRCA2 mutation who underwent population genetic screening.

There are two mutations in BRCA1 and one in BRCA2, which are present in up to 2.5% of Jewish women. Population genetic testing for Jewish women has been proposed; however, it is unclear how this would impact the uptake of cancer prevention options and psychosocial functioning in women with a positive result. Two thousand and eighty unselected Jewish women were tested for the Jewish BRCA mutations, and 1.1% were positive. Cancer-related distress was measured before testing, and at 1 and 2 years post-testing. Information on uptake of cancer risk reduction options was collected at 2 years. Breast and ovarian cancer risks were estimated using BRCAPRO. Within 2 years of receiving a positive result, 11.1% of women had prophylactic mastectomy, and 89.5% had a prophylactic oophorectomy. The mean breast cancer risk was estimated to be 37.2% at time of testing, compared to 20.9% at 2 years post-testing. The mean ovarian cancer risk was estimated to be 24.5% at time of testing, compared to 7.5% at 2 years following testing. Distress decreased between 1 and 2 years for women with prophylactic mastectomy and oophorectomy (P = 0.02), and for women with prophylactic oophorectomy only (P = 0.04) but not for those with neither surgery. The majority of Jewish women with a BRCA mutation identified through a population screening elected prophylactic oophorectomy, but a few had a prophylactic mastectomy. Uptake of either surgery resulted in decreased distress. Provision of population BRCA testing resulted in reduced risks of breast and ovarian cancers in women with a mutation.

Reasons for risk-reducing mastectomy versus MRI-screening in a cohort of women at high hereditary risk of breast cancer.

OBJECTIVE: To determine the reasons that motivate women in a cohort of women under intensive surveillance for breast cancer to undergo risk-reducing mastectomy (RRM). PATIENTS AND METHODS: Women with a BRCA1 or BRCA2 mutation who were enrolled in an MRI-based breast screening study were eligible to participate in this survey. A self-administered questionnaire was given to women who did, and who did not terminate annual MRI-based surveillance in order to undergo RRM. The questionnaire included information on family history, risk perception and satisfaction with screening. In addition, women were asked to provide the principal reason for their choice of having preventive surgery or not, and were asked about their satisfaction with this choice. RESULTS: 246 women without breast cancer participated in the study. Of these, 39 women (16%) elected to have RRM at some point after initiating screening. Although women who had a mother or sister with breast cancer were more likely to opt for RRM than were women with no affected first-degree relative (21% versus 10%) this did not reach statistical significance. Women who perceived their breast cancer risk to be greater than 50% were more likely to opt for RRM than were women who estimated their risk to be less than 50% (19% versus 6%). Fear of cancer was the most common reason cited for choosing to have RRM (38% of respondents) followed by having had a previous cancer, (25%), then concern over their children (16%). CONCLUSION: Among women with a BRCA mutation who are enrolled in an MRI-based screening program, a high perception of personal breast cancer risk and a history of breast cancer in a first-degree relative are predictors of the decision to have RRM.

Toenail selenium status and DNA repair capacity among female BRCA1 mutation carriers.

Selenium is an important cofactor of various antioxidant enzymes and has been shown to enhance DNA repair in normal human fibroblasts. Oral selenium supplementation has also been shown to decrease the number of chromosome breaks in BRCA1 mutation carriers. Because the predisposition to cancer among BRCA1 mutation carriers may be linked to high rates of DNA damage and chromosome breakage, we evaluated the association between toenail selenium concentrations and three measures of DNA repair capacity (the single-cell alkaline gel electrophoresis (comet) assay, the micronucleus test, and the enumeration of gamma-H2AX nuclear foci) in female BRCA1 mutation carriers and in non-carriers. Toenail selenium levels were inversely associated with levels of chromosomal damage following exposure to gamma-irradiation, as assessed by the micronucleus test. This association was limited to women with a BRCA1 mutation (p = 0.03). Toenail selenium was not a significant predictor of DNA repair capacity, as quantified by either the comet assay or the number of gamma-H2AX foci, in carriers or in non-carriers. These results provide evidence for a possible protective effect of selenium against BRCA1-associated breast cancers.

Screening for founder mutations in BRCA1 and BRCA2 in unselected Jewish women.

PURPOSE: There are two mutations in BRCA1 and one mutation in BRCA2 that are present in up to 2.5% of Ashkenazi Jewish women. Current guidelines for testing stipulate that a personal or family history of cancer be present to be eligible for testing. To date, population screening in this population has not been suggested. However, this may be rational. Little is known about the appropriateness of testing guidelines for the Jewish population or the level of interest in testing. METHODS: Eligible subjects were women who self-identified as Jewish, who were between the ages of 25 and 80 years, and who resided in Ontario. Subjects were recruited through an article in a national newspaper. Women were asked to complete a study questionnaire and a family history questionnaire and to provide a blood or saliva sample. The risk of carrying a BRCA mutation was estimated for each woman. Results A total of 2,080 women were enrolled onto the study. The overall mutation prevalence was 1.1% (0.5% for BRCA1 and 0.6% for BRCA2). Among the 22 mutation carriers, the mean estimate of carrying a BRCA mutation was 3.9%. Ten (45%) of the 22 women met the current Ontario Ministry of Health Guidelines criteria for testing. CONCLUSION: There is considerable interest for genetic testing among Jewish women at low risk of carrying a mutation. However, many women with mutations are ineligible for genetic testing under current guidelines. Approximately 1% of Jewish women carry a BRCA mutation, and these women should be considered to be candidates for genetic testing.

A BRCA1 mutation is not associated with increased indicators of oxidative stress.

BACKGROUND: Several functions have been attributed to the BRCA1 protein. A recent study suggests that BRCA1 is involved in the cellular antioxidant response by inducing the expression of genes involved in the antioxidant defense system and thus conferring resistance to oxidative stress. It is possible that individuals with a BRCA1 mutation might be susceptible to the effects of oxidative stress. The aim of this study was to evaluate whether women with a BRCA1 mutation exhibit increased indicators of oxidative stress. PATIENTS AND METHODS: We measured 3 markers of oxidative stress in vivo, the amounts of serum malondialdehyde and protein thiols, and 8-oxo-2'-deoxyguanosine (8-oxodG) levels in 25 unaffected BRCA1 mutation carriers and 25 noncarrier control subjects. RESULTS: There was no significant difference in serum malondialdehyde levels (P=.41), serum thiol levels (P=.85), or the number of 8-oxodG lesions (P=.49) in BRCA1 mutation carriers versus noncarriers. CONCLUSION: The results of this study suggest that the presence of a heterozygous BRCA1 mutation is not associated with increased levels of indicators of oxidative stress in serum or lymphocytes. Future studies are warranted to evaluate whether strategies aimed at minimizing oxidative stress might aid in the prevention of hereditary breast cancer.

Frequency of the CHEK2 1100delC mutation among women with breast cancer: an international study.

A founder allele in the CHEK2 gene (1100delC) has been associated with an elevated risk of breast cancer. This allele is responsible for the majority of CHEK2-associated breast cancers in women from northern European countries; however, within Europe, it seems to be rare in countries that are close to the Mediterranean. The frequency of the 1100delC allele has not been measured in non-White populations. We measured the frequency of the CHEK2 founder allele in 3,882 breast cancer patients and 8,609 controls from various countries. The allele was not seen among Asian patients (from Pakistan or the Philippines) and was present in 1 of 155 cases from Brazil. Among White women, the allele was present in 1.5% of 825 familial cases of breast cancer and in 0.7% of 1,106 patients with nonfamilial breast cancer. The allele was equally frequent in Jewish and non-Jewish patients. We estimate that the CHEK2 1100delC allele is associated with an odds ratio of 2.6 for breast cancer, which corresponds to a lifetime risk of approximately 24% in Ontario.

Identification of a novel truncating PALB2 mutation and analysis of its contribution to early-onset breast cancer in French-Canadian women.

BACKGROUND: PALB2 has recently been identified as a breast cancer susceptibility gene. PALB2 mutations are rare causes of hereditary breast cancer but may be important in countries such as Finland where a founder mutation is present. We sought to estimate the contribution of PALB2 mutations to the burden of breast cancer in French Canadians from Quebec. METHODS: We screened all coding exons of PALB2 in a sample of 50 French-Canadian women diagnosed with either early-onset breast cancer or familial breast cancer at a single Montreal hospital. The genetic variants identified in this sample were then studied in 356 additional women with breast cancer diagnosed before age 50 and in 6,448 newborn controls. RESULTS: We identified a single protein-truncating mutation in PALB2 (c.2323 C>T, resulting in Q775X) in 1 of the 50 high-risk women. This variant was present in 2 of 356 breast cancer cases and in none of 6,440 newborn French-Canadian controls (P = 0.003). We also identified two novel new non-synonymous single nucleotide polymorphisms in exon 4 of PALB2 (c.5038 A>G [I76V] and c.5156 G>T [G115V]). G115V was found in 1 of 356 cases and in 15 of 6,442 controls (P = 0.6). The I76V variant was not identified in either the extended case series or the controls. CONCLUSION: We have identified a novel truncating mutation in PALB2. The mutation was found in approximately 0.5% of unselected French-Canadian women with early-onset breast cancer and appears to have a single origin. Although mutations are infrequent, PALB2 can be added to the list of breast cancer susceptibility genes for which founder mutations have been identified in the French-Canadian population.

Analysis of PALB2/FANCN-associated breast cancer families.

No more than approximately 30% of hereditary breast cancer has been accounted for by mutations in known genes. Most of these genes, such as BRCA1, BRCA2, TP53, CHEK2, ATM, and FANCJ/BRIP1, function in DNA repair, raising the possibility that germ line mutations in other genes that contribute to this process also predispose to breast cancer. Given its close relationship with BRCA2, PALB2 was sequenced in affected probands from 68 BRCA1/BRCA2-negative breast cancer families of Ashkenazi Jewish, French Canadian, or mixed ethnic descent. The average BRCAPRO score was 0.58. A truncating mutation (229delT) was identified in one family with a strong history of breast cancer (seven breast cancers in three female mutation carriers). This mutation and its associated breast cancers were characterized with another recently reported but unstudied mutation (2521delA) that is also associated with a strong family history of breast cancer. There was no loss of heterozygosity in tumors with either mutation. Moreover, comparative genomic hybridization analysis showed major similarities to that of BRCA2 tumors but with some notable differences, especially loss of 18q, a change that was previously unknown in BRCA2 tumors and less common in sporadic breast cancer. This study supports recent observations that PALB2 mutations are present, albeit not frequently, in breast cancer families. The apparently high penetrance noted in this study suggests that at least some PALB2 mutations are associated with a substantially increased risk for the disease.