Internal Mammary Lymphadenopathy Does Not Impact Oncologic Outcomes in Patients Treated with Neoadjuvant Chemotherapy: Results from the I-SPY2 Clinical Trial.

BACKGROUND: Internal mammary lymphadenopathy (IML) plays a role in breast cancer stage and prognosis. We aimed to evaluate method of IML detection, how IML impacts response to neoadjuvant chemotherapy (NAC), and oncologic outcomes. METHODS: We evaluated patients enrolled in the I-SPY-2 clinical trial from 2010 to 2022. We captured the radiographic method of IML detection (magnetic resonance imaging [MRI], positron emission tomography/computed tomography [PET/CT], or both) and compared patients with IML with those without. Rates of locoregional recurrence (LRR), distant recurrence (DR) and event-free survival (EFS) were compared by bivariate analysis. RESULTS: Of 2095 patients, 198 (9.5%) had IML reported on pretreatment imaging. The method of IML detection was 154 (77.8%) MRI only, 11 (5.6%) PET/CT only, and 33 (16.7%) both. Factors associated with IML were younger age (p = 0.001), larger tumors (p < 0.001), and higher tumor grade (p = 0.027). Pathologic complete response (pCR) was slightly higher in the IML group (41.4% vs. 34.0%; p = 0.03). There was no difference in breast or axillary surgery (p = 0.41 and p = 0.16), however IML patients were more likely to undergo radiation (68.2% vs. 54.1%; p < 0.001). With a median follow up of 3.72 years (range 0.4-10.2), there was no difference between IM+ versus IM- in LRR (5.6% vs. 3.8%; p = 0.25), DR (9.1% vs. 7.9%; p = 0.58), or EFS (61.6% vs. 57.2%; p = 0.48). This was true for patients with and without pCR. CONCLUSIONS: In this large cohort of patients treated with NAC, outcomes were not negatively impacted by IML. We demonstrated that IML influences treatment selection but is not a poor prognostic indicator when treated with modern NAC and multidisciplinary disease management.

Clipping the Positive Lymph Node in Patients with Clinically Node Positive Breast Cancer Treated with Neoadjuvant Chemotherapy: Impact on Axillary Surgery in the ISPY-2 Clinical Trial.

BACKGROUND: For patients with clinically node-positive (cN+) breast cancer undergoing neoadjuvant chemotherapy (NAC), retrieving previously clipped, biopsy-proven positive lymph nodes during sentinel lymph node biopsy [i.e., targeted axillary dissection (TAD)] may reduce false negative rates. However, the overall utilization and impact of clipping positive nodes remains uncertain. PATIENTS AND METHODS: We retrospectively analyzed cN+ ISPY-2 patients (2011-2022) undergoing axillary surgery after NAC. We evaluated trends in node clipping and associations with type of axillary surgery [sentinel lymph node (SLN) only, SLN and axillary lymph node dissection (ALND), or ALND only] and event-free survival (EFS) in patients that were cN+ on a NAC trial. RESULTS: Among 801 cN+ patients, 161 (20.1%) had pre-NAC clip placement in the positive node. The proportion of patients that were cN+ undergoing clip placement increased from 2.4 to 36.2% between 2011 and 2021. Multivariable logistic regression showed nodal clipping was independently associated with higher odds of SLN-only surgery [odds ratio (OR) 4.3, 95% confidence interval (CI) 2.8-6.8, p < 0.001]. This was also true among patients with residual pathologically node-positive (pN+) disease. Completion ALND rate did not differ based on clip retrieval success. No significant differences in EFS were observed in those with or without clip placement, both with or without successful clip retrieval [hazard ratio (HR) 0.85, 95% CI 0.4-1.7, p = 0.7; HR 1.8, 95% CI 0.5-6.0, p = 0.3, respectively]. CONCLUSION: Clip placement in the positive lymph node before NAC is increasingly common. The significant association between clip placement and omission of axillary dissection, even among patients with pN+ disease, suggests a paradigm shift toward TAD as a definitive surgical management strategy in patients with pN+ disease after NAC.

Breast Conservation Surgery and Mastectomy Have Similar Locoregional Recurrence After Neoadjuvant Chemotherapy: Results From 1462 Patients on the Prospective, Randomized I-SPY2 Trial.

Neoadjuvant chemotherapy (NAC) increases rates of successful breast-conserving surgery (BCS) in patients with breast cancer. However, some studies suggest that BCS after NAC may confer an increased risk of locoregional recurrence (LRR). We assessed LRR rates and locoregional recurrence-free survival (LRFS) in patients enrolled on I-SPY2 (NCT01042379), a prospective NAC trial for patients with clinical stage II to III, molecularly high-risk breast cancer. Cox proportional hazards models were used to evaluate associations between surgical procedure (BCS vs mastectomy) and LRFS adjusted for age, tumor receptor subtype, clinical T category, clinical nodal status, and residual cancer burden (RCB). In 1462 patients, surgical procedure was not associated with LRR or LRFS on either univariate or multivariate analysis. The unadjusted incidence of LRR was 5.4% after BCS and 7.0% after mastectomy, at a median follow-up time of 3.5 years. The strongest predictor of LRR was RCB class, with each increasing RCB class having a significantly higher hazard ratio for LRR compared with RCB 0 on multivariate analysis. Triple-negative receptor subtype was also associated with an increased risk of LRR (hazard ratio: 2.91, 95% CI: 1.8-4.6, P < 0.0001), regardless of the type of operation. In this large multi-institutional prospective trial of patients completing NAC, we found no increased risk of LRR or differences in LRFS after BCS compared with mastectomy. Tumor receptor subtype and extent of residual disease after NAC were significantly associated with recurrence. These data demonstrate that BCS can be an excellent surgical option after NAC for appropriately selected patients.

Changes in Surgical Management of the Axilla Over 11 Years - Report on More Than 1500 Breast Cancer Patients Treated with Neoadjuvant Chemotherapy on the Prospective I-SPY2 Trial.

BACKGROUND: Axillary surgery after neoadjuvant chemotherapy (NAC) is becoming less extensive. We evaluated the evolution of axillary surgery after NAC on the multi-institutional I-SPY2 prospective trial. METHODS: We examined annual rates of sentinel lymph node (SLN) surgery with resection of clipped node, if present), axillary lymph node dissection (ALND), and SLN and ALND in patients enrolled in I-SPY2 from January 1, 2011 to December 31, 2021 by clinical N status at diagnosis and pathologic N status at surgery. Cochran-Armitage trend tests were calculated to evaluate patterns over time. RESULTS: Of 1578 patients, 973 patients (61.7%) had SLN-only, 136 (8.6%) had SLN and ALND, and 469 (29.7%) had ALND-only. In the cN0 group, ALND-only decreased from 20% in 2011 to 6.25% in 2021 (p = 0.0078) and SLN-only increased from 70.0% to 87.5% (p = 0.0020). This was even more striking in patients with clinically node-positive (cN+) disease at diagnosis, where ALND-only decreased from 70.7% to 29.4% (p < 0.0001) and SLN-only significantly increased from 14.6% to 56.5% (p < 0.0001). This change was significant across subtypes (HR-/HER2-, HR+/HER2-, and HER2+). Among pathologically node-positive (pN+) patients after NAC (n = 525) ALND-only decreased from 69.0% to 39.2% (p < 0.0001) and SLN-only increased from 6.9% to 39.2% (p < 0.0001). CONCLUSIONS: Use of ALND after NAC has significantly decreased over the past decade. This is most pronounced in cN+ disease at diagnosis with an increase in the use of SLN surgery after NAC. Additionally, in pN+ disease after NAC, there has been a decrease in use of completion ALND, a practice pattern change that precedes results from clinical trials.

Home Recovery After Mastectomy: Review of Literature and Strategies for Implementation American Society of Breast Surgeons Working Group.

BACKGROUND: Practices regarding recovery after mastectomy vary significantly, including overnight stay versus discharge same day. Expanded use of Enhanced Recovery After Surgery (ERAS) algorithms and the recent COVID pandemic have led to increased number of patients who undergo home recovery after mastectomy (HRAM). METHODS: The Patient Safety Quality Committee of the American Society of Breast Surgeons created a multispecialty working group to review the literature evaluating HRAM after mastectomy with and without implant-based reconstruction. A literature review was performed regarding this topic; the group then developed guidance for patient selection and tools for implementation. RESULTS: Multiple, retrospective series have reported that patients discharged day of mastectomy have similar risk of complications compared with those kept overnight, including risk of hematoma (0-5.1%). Multimodal strategies that improve nausea and analgesia improve likelihood of HRAM. Patients who undergo surgery in ambulatory surgery centers and by high-volume breast surgeons are more likely to be discharged day of surgery. When evaluating unplanned return to care, the only significant factors are African American race and increased comorbidities. CONCLUSIONS: Review of current literature demonstrates that HRAM is a safe option in appropriate patients. Choice of method of recovery should consider patient factors, such as comorbidities and social situation, and requires input from the multidisciplinary team. Preoperative education regarding pain management, drain care, and after-hour access to medical care are crucial components to a successful program. Additional investigation is needed as these programs become more prevalent to assess quality measures such as unplanned return to care, complications, and patient satisfaction.

Shaves off the Cavity or Specimen in Lumpectomy for Breast Cancer.

INTRODUCTION: Re-excision for positive margins (margins where tumor is positive) after breast conserving surgery (BCS) is common and burdensome for breast cancer patients. Routine shave margins can reduce positive margins and re-excision rates. Cavity shaving margin (CSM) removes margins from the lumpectomy cavity edges, whereas specimen shave margin (SSM) requires ex vivo removal of margins from the resected specimen. METHODS: We assessed breast cancer patients undergoing BCS who received CSM or SSM procedures from 2017 to 2019. CSM and SSM techniques were compared by analyzing positive rates of primary and final shaved margins, re-excision rates, and tissue volumes removed. RESULTS: Of 116 patients included in this study, 57 underwent CSM and 59 underwent SSM. Primary margins were positive or close in 19 CSM patients and 21 SSM patients (33% versus 36%; P = 0.798). Seventeen CSM patients had a tumor in shaved margin specimens, compared to four patients for SSM (30% versus 7%; P < 0.001); however, final shave margins were similar (5% versus 5%; P = 0.983). Volumes of shave specimens were higher with SSM (40.7 versus 13.4 cm3; P < 0.001), but there was no significant difference in the total volume removed (146.8 versus 134.4 cm3; P = 0.540). For tumors 2 cm or larger, the total volume removed (140 versus 206 cm3; P = 0.432) and rates of final margin positivity (7.5% versus 0%; P = 0.684) were similar for both techniques. CONCLUSIONS: CSM and SSM are effective techniques for achieving low re-excision rates. Our findings suggest that surgeons performing either CSM or SSM may maintain operative preferences and achieve similar results.

Symposium report: breast cancer in India-trends, environmental exposures and clinical implications.

PURPOSE: Incidence of breast cancer (BC), particularly in young women, are rising in India. Without population-based mammography screening, rising rates cannot be attributed to screening. Investigations are needed to understand the potential drivers of this trend. METHODS: An international team of experts convened to discuss the trends, environmental exposures, and clinical implications associated with BC in India and outlined recommendations for its management. RESULTS: Panels were structured across three major BC themes (n = 10 presentations). The symposium concluded with a semi-structured Think Tank designed to elicit short-term and long-term goals that could address the challenges of BC in India. CONCLUSION: There was consensus that the prevalence of late-stage BC and the high BC mortality rates are associated with the practice of detection, which is primarily through clinical and self-breast exams, as opposed to mammography. Triple-Negative BC (TNBC) was extensively discussed, including TNBC etiology and potential risk factors, the limited treatment options, and if reported TNBC rates are supported by rigorous scientific evidence. The Think Tank session yielded long-term and short-term goals to further BC reduction in India and included more regional etiological studies on environmental exposures using existing India-based cohorts and case-control studies, standardization for molecular subtyping of BC cases, and improving the public's awareness of breast health.

Complication Rates After Intraoperative Radiation Therapy: Do Applicator Size and Distance to Skin Matter?

BACKGROUND: Intraoperative radiation therapy (IORT) has gained popularity for early stage breast cancer treatment. Few studies have examined the relationship between complications and both demographic and technical factors. The objective of the current study was to determine if applicator size or distances to the skin were significant risk factors for complications. METHODS: Data was prospectively collected on patients who underwent lumpectomy followed by IORT from November 1, 2013 to August 31, 2018. Exclusion criteria included any prior radiation exposure or personal history of breast cancer. Comorbid conditions such as body mass index, diabetes, and smoking as well as technical specifications such as applicator size and distances to the skin were included for investigation. Student's t-test, Fisher's exact test, and odds ratios were utilized for statistical analysis. RESULTS: The study was comprised of 219 patients. None developed Clavien-Dindo grade 2 or above complications. Of 21.0% (n = 46) had minor complications. The most common complication was a palpable breast seroma (n = 37). Diabetes was the only comorbid condition with increased risk for complications (OR 3.2; 95% CI1.3-7.5; P = 0.008). The applicator sizes and average skin distances were similar between groups. Surprisingly, the closest skin distance was not a significant risk factor for post-operative complications (1.4 +/- 1.6 versus 1.4 +/- 1.9 cm; P = 1.0). CONCLUSION: Neither applicator size nor the closest skin distance were associated with increased complications. Traditionally described risk factors such as BMI and smoking were not predictive. This data provides support for potentially expanding the utilization for IORT without increasing complications.

Pain Management in Breast Surgery: Recommendations of a Multidisciplinary Expert Panel-The American Society of Breast Surgeons.

Opioid overdose accounted for more than 47,000 deaths in the United States in 2018. The risk of new persistent opioid use following breast cancer surgery is significant, with up to 10% of patients continuing to fill opioid prescriptions one year after surgery. Over prescription of opioids is far too common. A recent study suggested that up to 80% of patients receiving a prescription for opioids post-operatively do not need them (either do not fill the prescription or do not use the medication). In order to address this important issue, The American Society of Breast Surgeons empaneled an inter-disciplinary committee to develop a consensus statement on pain control for patients undergoing breast surgery. Representatives were nominated by the American College of Surgeons, the Society of Surgical Oncology, The American Society of Plastic Surgeons, and The American Society of Anesthesiologists. A broad literature review followed by a more focused review was performed by the inter-disciplinary panel which was comprised of 14 experts in the fields of breast surgery, anesthesiology, plastic surgery, rehabilitation medicine, and addiction medicine. Through a process of multiple revisions, a consensus was developed, resulting in the outline for decreased opioid use in patients undergoing breast surgery presented in this manuscript. The final document was reviewed and approved by the Board of Directors of the American Society of Breast Surgeons.

Pain Control in Breast Surgery: Survey of Current Practice and Recommendations for Optimizing Management-American Society of Breast Surgeons Opioid/Pain Control Workgroup.

INTRODUCTION: The opioid epidemic in the United States is a public health crisis. Breast surgeons are obligated to provide good pain control for their patients after surgery but also must minimize administration of narcotics to prevent a surgical episode of care from becoming a patient's gateway into opioid dependence. METHODS: A survey to ascertain pain management practice patterns after breast surgery was performed. A review of currently available literature that was specific to breast surgery was performed to create recommendations regarding pain management strategies. RESULTS: A total of 609 surgeons completed the survey and demonstrated significant variations in pain management practices, specifically within regards to utilization of regional anesthesia (e.g., nerve blocks), and quantity of prescribed narcotics. There is excellent data to guide the use of local and regional anesthesia. There are, however, fewer studies to guide narcotic recommendations; thus, these recommendations were guided by prevailing practice patterns. CONCLUSIONS: Pain management practices after breast surgery have significant variation and represent an opportunity to improve patient safety and quality of care. Multimodality approaches in conjunction with standardized quantities of narcotics are recommended.

Novel hyaluronan formulation for preventing acute skin reactions in breast during radiotherapy: a randomized clinical trial.

PURPOSE: We conducted a randomized, double-blind, vehicle-controlled clinical trial to investigate the use of a new proprietary hyaluronan (HA) formulation for the prevention of acute skin toxicity in breast cancer patients undergoing radiotherapy (RT). METHODS: Thirty women with breast cancer undergoing whole breast RT were enrolled. Each patient was randomly assigned to HA formulation (study cream, S) on the medial or lateral half of the irradiated breast and the control cream (placebo, P) on the other half. The primary endpoint was physician's evaluation of skin symptoms at week 5 during RT and week 2 post-RT. We also collected patients' independent assessment of skin after RT, patient's product preference, and an independent physician panel assessment of skin reactions based on photographs. RESULTS: Twenty-eight patients were evaluable. On physician's evaluation, there was no significant difference in radiation dermatitis between S and P and no overall preference to either cream at week 5 during or week 2 post-RT. More patients preferred S in evaluating skin appearance and skin reactions, but this did not reach statistical significance. Univariate analysis showed that physicians had an overall preference to the S cream at week 2 post-RT in patients with larger breasts. On the independent panel assessment, 3 reviewers saw no significant difference in radiation toxicity, whereas one reviewer reported better skin outcome with S cream at week 5. CONCLUSIONS: We found a nonstatistically significant patient preference but overall no significant radioprotective effects for this HA formulation compared with placebo except in patients with larger breasts. TRIAL REGISTRATION: The study was registered at www.clinicaltrials.gov (NCT02165605).

Benchmarking the American Society of Breast Surgeon Member Performance for More Than a Million Quality Measure-Patient Encounters.

BACKGROUND: Nine breast cancer quality measures (QM) were selected by the American Society of Breast Surgeons (ASBrS) for the Centers for Medicare and Medicaid Services (CMS) Quality Payment Programs (QPP) and other performance improvement programs. We report member performance. STUDY DESIGN: Surgeons entered QM data into an electronic registry. For each QM, aggregate "performance met" (PM) was reported (median, range and percentiles) and benchmarks (target goals) were calculated by CMS methodology, specifically, the Achievable Benchmark of Care™ (ABC) method. RESULTS: A total of 1,286,011 QM encounters were captured from 2011-2015. For 7 QM, first and last PM rates were as follows: (1) needle biopsy (95.8, 98.5%), (2) specimen imaging (97.9, 98.8%), (3) specimen orientation (98.5, 98.3%), (4) sentinel node use (95.1, 93.4%), (5) antibiotic selection (98.0, 99.4%), (6) antibiotic duration (99.0, 99.8%), and (7) no surgical site infection (98.8, 98.9%); all p values < 0.001 for trends. Variability and reasons for noncompliance by surgeon for each QM were identified. The CMS-calculated target goals (ABC™ benchmarks) for PM for 6 QM were 100%, suggesting that not meeting performance is a "never should occur" event. CONCLUSIONS: Surgeons self-reported a large number of specialty-specific patient-measure encounters into a registry for self-assessment and participation in QPP. Despite high levels of performance demonstrated initially in 2011 with minimal subsequent change, the ASBrS concluded "perfect" performance was not a realistic goal for QPP. Thus, after review of our normative performance data, the ASBrS recommended different benchmarks than CMS for each QM.

Select Choices in Benign Breast Disease: An Initiative of the American Society of Breast Surgeons for the American Board of Internal Medicine Choosing Wisely® Campaign.

BACKGROUND: Up to 50% of all women encounter benign breast problems. In contrast to breast cancer, high-level evidence is not available to guide treatment. Management is therefore largely based on individual physician experience/training. The American board of internal medicine (ABIM) initiated its Choosing Wisely® campaign to promote conversations between patients and physicians about challenging the use of tests or procedures which may not be necessary. The American society of breast surgeons (ASBrS) Patient safety and quality committee (PSQC) chose to participate in this campaign in regard to the management of benign breast disease. METHODS: The PSQC solicited initial candidate measures. PSQC surgeons represent a wide variety of practices. The resulting measures were ranked by modified Delphi appropriateness methodology in two rounds. The final list was approved by ASBrS and endorsed by the ABIM. RESULTS: The final five measures are as follows. (1) Don't routinely excise areas of pseuodoangiomatous stromal hyperplasia (PASH) of the breast in patients who are not having symptoms from it. (2) Don't routinely surgically excise biopsy-proven fibroadenomas that are < 2 cm. (3) Don't routinely operate for a breast abscess without an initial attempt to percutaneously aspirate. (4) Don't perform screening mammography in asymptomatic patients with normal exams who have less than a 5-years life expectancy. (5) Don't routinely drain nonpainful, fluid-filled cysts. CONCLUSIONS: The ASBrS Choosing Wisely® measures that address benign breast disease management are easily accessible to patients via the internet. Consensus was reached by PSQC regarding these recommendations. These measures provide guidance for shared decision-making.

Mammographic density changes in surgical weight loss-an indication for personalized screening.

BACKGROUND: Obesity and high radiologic breast density independently increase breast cancer risk. We evaluated the effect of surgical weight loss on mammographic density (MD). METHODS: Patients undergoing bariatric surgery and screening mammography (MG) were identified, data regarding demographics, comorbidities, calculated and genetic breast cancer risk was collected. Patients had a MG before and after surgery. Fellowship-trained breast radiologists assigned Breast Imaging Reporting and Data System density categories. RESULTS: Patients underwent sleeve gastrectomy (n = 56) or gastric bypass (n = 7), 78% had hypertension, 48% had diabetes. Four had deleterious BRCA mutations, four were calculated high risk. Mean weight loss = 28.7 kg. Mean initial BMI = 44.3 kg/m2 (range:33-77), final BMI = 33.6 kg/m2 (range:20-62;p < 0.01). Density was unchanged in 53, decreased in 1, increased in 9. Of these 9(14%), 5 changed from almost entirely fatty to scattered MD, and 4 changed from scattered MD to heterogeneously dense. Mean weight loss of the 9 with increased MD was greater than the cohort (37.7vs.28.7 kg;p < 0.01). CONCLUSIONS: Surgical weight loss increased MD in 14%. Increased MD masks malignancies, patients may benefit from additional screening based on calculated risk assessments that include MD.

Bracketed radioactive seed localization vs bracketed wire-localization in breast surgery.

Multiple localizers placed in a bracketed fashion facilitates excision of radiographically extensive breast lesions. In this study, bracketed radioactive seed localization (bRSL) was compared to bracketed wire localization (bWL). We hypothesized that bRSL would achieve adequate margins and decrease re-operation rates with similar or less specimen volumes (SV) than bWL. Retrospective review identified patients who underwent bracketed breast procedures at an academic medical center. Data collected included patient demographics, tumor features, treatment variables, and surgical outcomes. Wilcoxon rank-sum test and chi-square test were used to compare continuous and categorical data, respectively. A multivariable logistic regression model was used to evaluate the association between re-excision and localization technique after adjusting for clinically relevant variables. Patients who underwent bWL were 3.9 times more likely to undergo re-excision compared to patients in bRSL group (OR=3.9, 95% CI: 2.0-7.4). Initial and total SV did not significantly differ between the two groups (P=.4). Patients were significantly more likely to undergo a mastectomy in the bWL group than in the bRSL group (24% vs 7%; P<.01). For patients undergoing excision of radiologically extensive breast lesions, bRSL serves as an alternative to bWL. In this retrospective study, bRSL was associated with a decreased re-excision rate with similar SV and a lower rate of mastectomy when compared to bWL.

Genetic Ancestry using Mitochondrial DNA in patients with Triple-negative breast cancer (GAMiT study).

BACKGROUND: Triple-negative breast cancer (TNBC) lacks estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2)/neu receptors, and is aggressive and therapeutically challenging. Genetic ancestry testing is an emerging medical field. Mitochondrial DNA (mtDNA), which is distinct from nuclear DNA, is maternally inherited and allows for origin determination. Patients with TNBC tend to be younger and are more likely to be African American, making this an ideal disease for mtDNA exploration. To the authors' knowledge, the current study is the first to perform mtDNA for self-described African American, White, and Hispanic patients with TNBC to identify mtDNA patterns. METHODS: Patients with TNBC who were at any stage of therapy/survivorship were included. Self-reported ethnicity was confirmed at the time of the prospective buccal swab. Haplogroup prediction was performed on sequencing of hypervariable region 1. Using sequence similarity scores and lineage databases, sequence patterns were determined. Data regarding presentation and treatment, tumor features, and outcomes was collected. RESULTS: A total of 92 patients were included: 31 self-described African American, 31 White, and 30 Hispanic individuals. Hispanic patients were found to have the largest tumor size (4.5 cm; P = .01) and youngest age (41 years; P<.0001). Eight patients were BRCA1/2 mutation carriers. There were no differences noted among groups with regard to surgery, lymph node metastases, or survival. Analysis revealed Nigerian, Cameroon, or Sierra Leone ancestry and haplogroups A, U, H, or B to be the most common mtDNA patterns. Twelve discordances (13%) between mtDNA analysis and self-described ethnicity were identified among the 92 patients. The highest discordance (26%; 8 patients) was noted in self-described Hispanic patients: 3 had Nigerian ancestry, and 1 individual demonstrated haplogroup K mtDNA (Ashkenazi Jewish ancestry). CONCLUSIONS: Discordance between self-reported ethnicity and mtDNA analysis was identified in 13% of patients with TNBC. The identification of mtDNA patterns with a predisposition toward TNBC may allow for risk stratification. Cancer 2017;107-113. © 2016 American Cancer Society.