Assessment of the effect of the American Society of Breast Surgery guidelines on contralateral prophylactic mastectomy rates for unilateral breast cancer.

BACKGROUND: In July 2016, the American Society of Breast Surgeons published guidelines discouraging contralateral prophylactic mastectomy for average-risk women with unilateral breast cancer. We incorporated these into practice with structured patient counseling and aimed to assess the effect of this initiative on contralateral prophylactic mastectomy rates. METHODS: We evaluated female patients with unilateral breast cancer undergoing mastectomy at our institution from January 2011 to November 2022. Variables associated with contralateral prophylactic mastectomy and trends over time were analyzed using the Wilcoxon rank sum test or χ2 analysis as appropriate. RESULTS: Among 3,208 patients, (median age 54 years) 1,366 (43%) had a unilateral mastectomy, and 1,842 (57%) also had a concomitant contralateral prophylactic mastectomy. Across all patients, contralateral prophylactic mastectomy rates significantly decreased post-implementation from 2017 to 2019 (55%) vs 2015 to 2016 (62%) (P = .01) but increased from 2020 to 2022 (61%). Immediate breast reconstruction rate was 70% overall (81% with contralateral prophylactic mastectomy and 56% without contralateral prophylactic mastectomy, P < .001). Younger age, White race, mutation status, and earlier stage were also associated with contralateral prophylactic mastectomy. Genetic testing increased from 27% pre-guideline to 74% 2020 to 2022, as did the proportion of patients with a pathogenic variant (4% pre-guideline vs 11% from 2020-2022, P < .001), of whom 91% had a contralateral prophylactic mastectomy. Among tested patients without a pathogenic variant and patients not tested, contralateral prophylactic mastectomy rates declined from 78% to 67% and 48% to 38% pre -and post-guidelines, respectively, P < .001. CONCLUSION: Implementation of specific patient counseling was effective in decreasing contralateral prophylactic mastectomy rates. While recognizing that patient choice plays a significant role in the decision for contralateral prophylactic mastectomy, further educational efforts are warranted to affect contralateral prophylactic mastectomy rates, particularly in the setting of negative genetic testing.

When left does not seem right: epigenetic and bioelectric differences between left- and right-sided breast cancer.

BACKGROUND: During embryogenesis lateral symmetry is broken, giving rise to Left/Right (L/R) breast tissues with distinct identity. L/R-sided breast tumors exhibit consistently-biased incidence, gene expression, and DNA methylation. We postulate that a differential L/R tumor-microenvironment crosstalk generates different tumorigenesis mechanisms. METHODS: We performed in-silico analyses on breast tumors of public datasets, developed xenografted tumors, and conditioned MDA-MB-231 cells with L/R mammary extracts. RESULTS: We found L/R differential DNA methylation involved in embryogenic and neuron-like functions. Focusing on ion-channels, we discovered significant L/R epigenetic and bioelectric differences. Specifically, L-sided cells presented increased methylation of hyperpolarizing ion channel genes and increased Ca2+ concentration and depolarized membrane potential, compared to R-ones. Functional consequences were associated with increased proliferation in left tumors, assessed by KI67 expression and mitotic count. CONCLUSIONS: Our findings reveal considerable L/R asymmetry in cancer processes, and suggest specific L/R epigenetic and bioelectric differences as future targets for cancer therapeutic approaches in the breast and many other paired organs.

Clinical practice of breast cancer protontherapy: A single-centre experience from selection to treatment.

PURPOSE: Breast protontherapy efficiently limits cardiac, lung and contralateral breast exposure, which may clinically translate into better late tolerance profile compared with classic photon techniques. While breast protontherapy is already implemented in the United States and in some European countries, clinical experience of breast cancer protontherapy is currently limited in France. The aim of this study is to evaluate the clinical practice of breast cancer protontherapy at the Institut Curie in order to implement this technique at a larger scale. MATERIALS AND METHODS: Data from all breast cancer patients that have been addressed to the protontherapy centre of Orsay (CPO, Institut Curie) for adjuvant breast protontherapy were retrieved. We analysed why these patients were ultimately treated with protontherapy or not. RESULTS: Between November 2019 and November 2020, eleven breast cancer patients have been evaluated for adjuvant protontherapy at the CPO. Two of them were ultimately treated with proton beams; adjuvant breast protontherapy therapy was well tolerated. The nine other patients were not treated with protontherapy due to lack of availability of protontherapy treatment rooms in acceptable time limits, at the time of patient evaluation. CONCLUSION: Despite dosimetric advantages and excellent clinical tolerance, lack of availability of protontherapy machines currently limits wider implementation of breast protontherapy.

The Angelina Jolie effect: Contralateral risk-reducing mastectomy trends in patients at increased risk of breast cancer.

Contralateral risk-reducing mastectomy (CRRM) rates have tripled over the last 2 decades. Reasons for this are multi-factorial, with those harbouring a pathogenic variant in the BRCA1/2 gene having the greatest survival benefit. On May 14th, 2013, Angelina Jolie shared the news of her bilateral risk-reducing mastectomy (BRRM), on the basis of her BRCA1 pathogenic variant status. We evaluated the impact of this news on rates of CRRM in women with increased risk for developing breast cancer after being diagnosed with unilateral breast cancer. The prospective cohort study included all women with at least a moderate lifetime risk of developing breast cancer who attended our family history clinic (1987-2019) and were subsequently diagnosed with unilateral breast cancer. Rates of CRRM were then compared between patients diagnosed with breast cancer before and after Angelina Jolie's announcement (pre- vs. post-AJ). Of 386 breast cancer patients, with a mean age at diagnosis of 48 ± 8 years, 268 (69.4%) were diagnosed in the pre-AJ period, and 118 (30.6%) in the post-AJ period. Of these, 123 (31.9%) underwent CRRM, a median 42 (interquartile range: 11-54) days after the index cancer surgery. Rates of CRRM doubled following AJ's news, from 23.9% pre-AJ to 50.0% post AJ (p < 0.001). Rates of CRRM were found to decrease with increasing age at breast cancer (p < 0.001) and tumour TNM stage (p = 0.040), and to increase with the estimated lifetime risk of breast cancer (p < 0.001) and tumour grade (p = 0.015) on univariable analysis. After adjusting for these factors, the step-change increase in CRRM rates post-AJ remained significant (odds ratio: 9.61, p < 0.001). The AJ effect appears to have been associated with higher rates of CRRM amongst breast cancer patients with increased cancer risk. CRRM rates were highest amongst younger women and those with the highest lifetime risk profile. Clinicians need to be aware of how media news can impact on the delivery of cancer related services. Communicating objective assessment of risk is important when counselling women on the merits of risk-reducing surgery.

ATM Variants in Breast Cancer: Implications for Breast Radiation Therapy Treatment Recommendations.

PURPOSE: Advances in germline genetic testing have led to a surge in identification of ataxia-telangiectasia mutated (ATM) variant carriers among breast cancer patients, raising numerous questions regarding use of breast radiation therapy (RT) in this population. METHODS: A literature search using PubMed identified articles assessing association(s) between the germline ATM variant status and the risk of toxicity after breast RT. An expert panel of breast radiation oncologists, genetic counselors, and basic scientists convened to review the association between ATM variants and radiation-induced toxicity or secondary malignancy risk and to determine any impact on breast RT recommendations. RESULTS: Carriers of pathogenic variants in ATM have a 2- to 4-fold increased risk for developing breast cancer. ATM variants do not consistently increase risks of toxicities after RT, except possibly among patients with the single nucleotide variant c5557G>A (rs1801516), in whom a small increased risk for the development of both acute and late radiation effects has been identified. In most breast cancer patients with ATM variants, the excess 5-year absolute risk of developing a secondary contralateral breast cancer (CBC) after radiation is extremely low. The exception is in women younger than 45 years old with deleterious rare ATM missense variants, who may be at higher risk for developing a radiation-induced CBC over time. CONCLUSIONS: Adjuvant radiation is safe for most breast cancer patients who harbor ATM variants. The possible exceptions are patients with the variant c5557G>A (rs1801516) and patients younger than 45 years old with certain rare deleterious ATM variants, who may be at higher risk for developing CBC. These latter patients should be counseled regarding this potential risk, and every effort should be made to minimize the contralateral breast dose. However, the inconsistency of published data limits precise recommendations, magnifying the need for further prospective studies and the development of a centralized database cataloging RT outcomes and genetic status.

Locoregional Treatments and Ipsilateral Breast Cancer Recurrence Rates in BRCA1/2 Mutation Carriers.

PURPOSE: There is a paucity of data on the rates of ipsilateral breast tumor recurrence (IBTR) in BRCA1/2-associated breast cancer (BC). Scarcer yet are outcomes data in BRCA1/2 mutation carriers in the setting of newer mastectomy techniques, such as skin-sparing mastectomies (SSM) and nipple-sparing mastectomies (NSM). METHODS: Data were extracted from the medical records of BRCA1/2 carriers who were diagnosed with BC and treated at a single institution between 2006 and 2020. The data extracted included patient demographics, tumor characteristics, disease stage, surgical treatment, use of radiation therapy (RT), and disease outcome. RESULTS: Overall, 255 BC patients with BRCA1/2 germline mutations were identified. Of these, 128 (50.2%) underwent a mastectomy (SSM or NSM in 82% of them), 76 (59.4%) without postmastectomy RT (non-PMRT) and 52 (40.6%) with PMRT, whereas 127 (49.8%) elected for breast-conserving treatment (BCT). The non-PMRT group had earlier disease stages (82.3% were Tis and T1N0) compared with the PMRT and BCT groups (3.6% and 48.1%, respectively; P < .05). The IBTR cumulative rate was 9 of 76 (11.8%) in the non-PMRT cohort compared with 0 of 52 in the PMRT group (P = .01) and 6 of 127 (4.7%) in the BCT group (P = .06). The cumulative incidences of IBTR at 5 and 10 years were 9.8% and 27.4%, respectively, in the non-PMRT group versus 2% and 11.3%, respectively, in the BCT group (P = .0183). No significant difference in overall survival was observed at the time of follow-up. CONCLUSIONS: BRCA1/2 mutation carriers treated with mastectomy without PMRT had higher rates of IBTR than those who underwent mastectomy and PMRT or BCT, despite earlier stages of disease. The safety of SSM/NSM should be evaluated in a prospective trial.

Clinical phenotypes combined with saturation genome editing identifying the pathogenicity of BRCA1 variants of uncertain significance in breast cancer.

Characterizing the pathogenicity of BRCA1 variants of uncertain significance (VUSs) is a major bottleneck in clinical management of BRCA1-associated breast cancer. Saturation genome editing (SGE) was recently reported as an innovative laboratory-based approach to assess the pathogenicity of BRCA1 variants. We combined clinical phenotypes and SGE score to identify the pathogenicity of BRCA1 VUSs detected in a cohort of 8,085 breast cancer patients. According to SGE function score, 33 out of 144 BRCA1 VUSs detected were classified into "loss of function" (n = 13), "intermediate" (n = 2), and "functional" (n = 18) groups. Compared with non-carriers, "loss of function" VUS carriers (n = 19) presented significantly worse clinicopathological characteristics. These included younger age at breast cancer diagnosis (44.4 years vs. 51.2 years, P = 0.01), stronger family history of any cancer (57.9% vs. 32.3%, P = 0.017) especially breast or ovarian cancer (47.4% vs. 9.3%, P < 0.001), more bilateral breast cancer (31.6% vs. 3.4%, P < 0.001), and triple-negative breast cancer (47.4% vs. 12.8%, P < 0.001), which were comparable to those of pathogenic variant carriers. In contrast, the clinical phenotypes of "functional" VUS carriers were similar to those of non-carriers. These results indicated that SGE was a reliable method in BRCA1 variant classification. Combining SGE function score and the available evidence, twelve out of 33 BRCA1 VUSs were reclassified as pathogenic or likely pathogenic variants and one was benign.

Contralateral Risk-Reducing Mastectomy in Breast Cancer Patients Who Undergo Multigene Panel Testing.

BACKGROUND: An increasing number of breast cancer patients are undergoing expanded genetic testing and are being identified as germline mutation carriers. We sought to determine rates of contralateral risk-reducing mastectomy (CRRM) in patients with various germline mutations. PATIENTS AND METHODS: All women ≥ 18 years of age with unilateral breast cancer who underwent multigene panel testing between January 1, 2014 and August 1, 2019 at our academic institution were identified. Demographic, tumor, and treatment variables were identified from the medical record. Multivariable analyses were performed to compare factors associated with performance of CRRM. RESULTS: We identified 1613 patients, of whom 28.1% had a pathogenic variant and 40.1% had variants of uncertain significance (VUS). Overall, 420 patients (26.0%) underwent a CRRM. On multivariable analysis, factors associated with CRRM included age < 50 years (OR 3.8, 95% CI 3.0, 5.0), race (OR 0.5, 95% CI 0.3, 0.7 and OR 0.4, 95% CI 0.2, 0.7 for Black and Asian women, respectively, versus White women), and the presence of any germline mutation or VUS (OR 13.2, 95% CI 8.7, 20.2 for BRCA1/2; OR 3.9, 95% CI 2.7, 5.8 for non-BRCA germline mutation; and OR 1.8, 95% CI 1.3, 2.6 for VUS). CONCLUSIONS: In breast cancer patients who undergo multigene panel testing, a sizeable number of women with pathogenic non-BRCA germline findings are opting for CRRM. Given that the risk of contralateral breast cancer in women with most pathogenic mutations other than BRCA1/2 remains poorly characterized, these data have implications for risk counseling and for ascertaining the true risks of contralateral breast cancer in this population.

Prevalence of pathogenic BRCA1/2 germline mutations among 802 women with unilateral triple-negative breast cancer without family cancer history.

BACKGROUND: There is no international consensus up to which age women with a diagnosis of triple-negative breast cancer (TNBC) and no family history of breast or ovarian cancer should be offered genetic testing for germline BRCA1 and BRCA2 (gBRCA) mutations. Here, we explored the association of age at TNBC diagnosis with the prevalence of pathogenic gBRCA mutations in this patient group. METHODS: The study comprised 802 women (median age 40 years, range 19-76) with oestrogen receptor, progesterone receptor, and human epidermal growth factor receptor type 2 negative breast cancers, who had no relatives with breast or ovarian cancer. All women were tested for pathogenic gBRCA mutations. Logistic regression analysis was used to explore the association between age at TNBC diagnosis and the presence of a pathogenic gBRCA mutation. RESULTS: A total of 127 women with TNBC (15.8%) were gBRCA mutation carriers (BRCA1: n = 118, 14.7%; BRCA2: n = 9, 1.1%). The mutation prevalence was 32.9% in the age group 20-29 years compared to 6.9% in the age group 60-69 years. Logistic regression analysis revealed a significant increase of mutation frequency with decreasing age at diagnosis (odds ratio 1.87 per 10 year decrease, 95%CI 1.50-2.32, p < 0.001). gBRCA mutation risk was predicted to be > 10% for women diagnosed below approximately 50 years. CONCLUSIONS: Based on the general understanding that a heterozygous mutation probability of 10% or greater justifies gBRCA mutation screening, women with TNBC diagnosed before the age of 50 years and no familial history of breast and ovarian cancer should be tested for gBRCA mutations. In Germany, this would concern approximately 880 women with newly diagnosed TNBC per year, of whom approximately 150 are expected to be identified as carriers of a pathogenic gBRCA mutation.

Oncologic Safety of Prophylactic Nipple-Sparing Mastectomy in a Population With BRCA Mutations: A Multi-institutional Study.

Importance: Nipple-sparing mastectomy (NSM) offers superior cosmetic outcomes and has been gaining wide acceptance; however, its role among patients with BRCA mutations remains controversial. Objective: To report on the oncologic safety of NSM and provide evidence-based data to patients and health care professionals regarding preservation of the nipple-areolar complex during a risk-reducing mastectomy in a population with BRCA mutations. Design, Setting, and Participants: We retrospectively reviewed the outcomes of 9 institutions' experience with prophylactic NSM from 1968 to 2013 in a cohort of patients with BRCA mutations. Patients with breast cancer were included if they underwent contralateral risk-reducing mastectomy; however, only the prophylactic side was considered in the analysis. Patients found to have an occult primary breast cancer at the time of risk-reducing mastectomy, those having variant(s) of unknown significance, and those undergoing free nipple grafts were excluded. Main Outcomes and Measures: The primary outcome measure was development of a new breast cancer after risk-reducing NSM. Three reference data sources were used to model the expected number of events, and this was compared with our observed number of events. Results: A total of 548 risk-reducing NSMs in 346 patients were performed at 9 institutions. The median age at NSM was 41 years (interquartile range, 34.5-47.5 years). Bilateral prophylactic NSMs were performed in 202 patients (58.4%), and 144 patients (41.6%) underwent a unilateral risk-reducing NSM secondary to cancer in the contralateral breast. Overall, 201 patients with BRCA1 mutations and 145 with BRCA2 mutations were included. With median and mean follow-up of 34 and 56 months, respectively, no ipsilateral breast cancers occurred after prophylactic NSM. Breast cancer did not develop in any patients undergoing bilateral risk-reducing NSMs. Using risk models for BRCA1/2 mutation carriers, approximately 22 new primary breast cancers were expected without prophylactic NSM. Prophylactic NSM resulted in a significant reduction in breast cancer events (test of observed vs expected events, P < .001). Conclusions and Relevance: Nipple-sparing mastectomies are highly preventive against breast cancer in a BRCA population. Although the follow-up remains relatively short, NSM should be offered as a breast cancer risk-reducing strategy to appropriate patients with BRCA mutations.

Impact that Timing of Genetic Mutation Diagnosis has on Surgical Decision Making and Outcome for BRCA1/BRCA2 Mutation Carriers with Breast Cancer.

BACKGROUND: Deleterious BRCA mutation carriers with breast cancer are at increased risk for additional breast cancer events. This study evaluated the impact that timing of identification of BRCA+ status has on surgical decision and outcome. METHODS: The authors reviewed all BRCA carriers at their institution whose breast cancer was diagnosed between January 1996 and June 2015. Patient surveys, medical records, and institutional databases were used to collect data. Differences in surgical choice were analyzed using the chi-square test, and rates of subsequent breast cancer events were estimated using the Kaplan-Meier method. RESULTS: The study investigated 173 BRCA carriers with breast cancer (100 BRCA1, 73 BRCA2). Of the women with known BRCA mutation before surgery and unilateral stages 0 to 3 breast cancer (n = 63), 12.7 % underwent lumpectomy, 4.8 % underwent unilateral mastectomy (UM), and 82.5 % underwent bilateral mastectomy (BM). These surgical choices differed significantly (p < 0.0001) from those of patients unaware of their mutation at the time of surgery (n = 93) (51.6 % had lumpectomy, 19.4 % had UM, 29 % had BM). Of the patients with BRCA mutation identified after surgery who underwent lumpectomy or UM, 36 (59 %) of 66 underwent delayed BM. The patients with BRCA+ known before diagnosis presented with significantly lower-stage disease (p = 0.02) at diagnosis (69 % stage 0 or 1) than those whose BRCA mutation was identified after cancer diagnosis (40 % stage 0 or 1). CONCLUSIONS: The study findings showed that BRCA mutation status influences surgical decision. The rates of BM were higher for the patients with BRCA mutation known before surgery. Identification of BRCA mutation after surgery frequently leads to subsequent breast surgery. Genetic testing before surgery is important for patients at elevated risk for BRCA mutation.

Surgeons' Perspectives of Contralateral Prophylactic Mastectomy.

BACKGROUND: Contralateral prophylactic mastectomy (CPM) is commonly performed for the treatment of breast cancer, despite its limited oncologic benefit. Little is known about surgeons' perceptions of performing CPM. We hypothesized that a proportion of surgeons would report discomfort with performing CPM, particularly when there is discordance between patients' perceived benefit from CPM and the expected oncologic benefit. METHODS: A survey was sent to members of the American Society of Breast Surgeons seeking self-reports of surgeons' practice patterns, perceptions, and comfort levels with CPM. RESULTS: Of the 2436 members surveyed, 601 responded (response rate = 24.7 %). The median age of respondents was 52 years, and 59 % of responders were women. The majority (58 %) reported that 80 % of their practice was devoted to the treatment of breast disease. Fifty-seven percent (n = 326) of respondents reported discomfort with performing CPM at some point in their practice. While most surgeons (95 %) were comfortable with CPM on a patient with a deleterious BRCA mutation, only 34 % were comfortable performing CPM on an average-risk patient. The most common reasons reported for surgeon discomfort with CPM were a concern for overtreatment, an unfavorable risk/benefit ratio, and inadequate patient understanding of the anticipated risks and benefits of CPM. CONCLUSIONS: Despite the increasing use of CPM for the treatment of breast cancer, many surgeons report discomfort with CPM. Concerns with performing CPM predominantly focus on ambiguities surrounding the oncologic benefit and relative risk of this procedure. Further research is needed to define optimal shared decision-making practices in this area.

Trends in Media Reports of Celebrities' Breast Cancer Treatment Decisions.

BACKGROUND: Although the increasing use of bilateral mastectomies is multifaceted, one source of influence may be the media, including coverage of celebrity breast cancer treatment. We examined trends in media reporting that might impact decision making among women with breast cancer. METHODS: We performed searches of two comprehensive online databases for articles from major U.S. print publications mentioning celebrities and terms related to the word "breast" and terms related to cancer treatment. Automated analysis using custom-created dictionaries was used to determine word frequencies over time. An analysis of net media tone was conducted using Lexicoder Sentiment Dictionaries. RESULTS: Celebrity breast cancer media reports significantly increased since 2004 (p < .05). Dramatic increases in bilateral mastectomy articles occurred in 2008-2009, with an increase in net positive tone. The surgical treatment was significantly more likely to be mentioned when a celebrity had bilateral mastectomies than unilateral mastectomy or breast conservation (44.8 vs 26.1 %, p < .001). The majority (60 %) of articles on celebrities undergoing bilateral mastectomy for cancer had no mention of genetics, family history, or risk. CONCLUSIONS: Media reports of celebrity breast cancer present a bias toward bilateral mastectomies in both frequency and tone. This may sway public opinion, particularly when factors such as risk and genetics are excluded. Surgeons need to work with the media to improve cancer reporting and identify methods to better educate patients prior to surgical consultations.