Dose dense doxorubicin plus cyclophosphamide in a modified KEYNOTE522 regimen for triple negative breast cancer.

The KEYNOTE-522 (KN522) regimen for neoadjuvant treatment of triple negative breast cancer (TNBC) utilized q3week dosing for doxorubicin plus cyclophosphamide (AC); however, dose-dense AC (ddAC) has demonstrated superior overall survival (OS) compared to q3week AC in anthracycline and taxane-based regimens. We performed a retrospective analysis assessing the use of ddAC in KN522 and the impact of sequencing ddAC before or after carboplatin/paclitaxel (CbT) plus pembrolizumab on multiple outcomes. 128 patients with TNBC were included. Overall pathologic complete response (pCR) rate of 56%. Sequencing of ddAC vs CbT first showed no difference in pCR rate (ddAC 55% vs. CbT 58%, p = 0.77). However, ddAC first compared to CbT first correlated with a significant increase in the incidence of overall treatment delays (ddAC 70% vs. CbT 51%, p = 0.03), with cytopenias most frequent (ddAC 59% vs. CbT 31%, p = 0.001). ddAC in a modified KN522 regimen is safe, tolerable, and effective. Efficacy is comparable regardless of chemotherapy sequencing, but ddAC first is significantly associated with higher rates of treatment delays and cytopenias.

Impact of Neoadjuvant Chemoimmunotherapy on Surgical Outcomes and Time to Radiation in Triple-Negative Breast Cancer.

BACKGROUND: We examined the association between immunotherapy-containing and standard chemotherapy regimens with treatment delays and postoperative complications in stage II-III triple-negative breast cancer. The effect of immune-related adverse events (irAEs) was compared. PATIENTS AND METHODS: We compared 139 women treated with neoadjuvant pembrolizumab plus chemotherapy (KEYNOTE-522 regimen) from August 2021 to September 2022 with 287 consecutive patients who received neoadjuvant chemotherapy alone prior to July 2021 and underwent surgery. Baseline characteristics, time to treatments, and surgical complications were compared using two-sample non-parametric tests. Linear regression evaluated association of irAEs with time to surgery and radiation. Logistic regression identified factors associated with surgical complications. RESULTS: Age, body mass index, race, American Society of Anesthesiologists (ASA) class, and mastectomy rates were similar among cohorts. No clinically relevant difference in time from end of neoadjuvant treatment to surgery was observed [KEYNOTE-522: median 32 (IQR 27, 43) days; non-KEYNOTE-522: median 31 (IQR 26, 37) days; P = 0.048]. Time to radiation did not differ (P = 0.7). A total of 26 patients (9%; non-KEYNOTE-522) versus 11 (8%; KEYNOTE-522) experienced postoperative complications (P = 0.6). In the KEYNOTE-522 cohort, 59 (43%) of 137 patients experienced 82 irAEs; 40 (68%) required treatment. Older age (P = 0.018) and ASA class 4 (P = 0.007) were associated with delays to surgery after adjusting for clinical factors. Experiencing ≥ 1 irAE was associated with delay to radiation (P = 0.029). IrAEs were not associated with surgical complications (P = 0.4). CONCLUSIONS: We observed no clinically meaningful difference between times to surgery/adjuvant radiation or postoperative complications and type of preoperative chemotherapy. IrAEs were associated with delay to adjuvant radiation but not with postoperative complications or delay to surgery.

Lower limb revascularization leads to faster walking but with less efficient mechanics in claudicating patients.

Peripheral artery disease (PAD) is characterized by reduced blood flow to the extremities due to atherosclerosis. Studies report impaired gait mechanics in patients with lower extremity PAD. We hypothesized that revascularization surgery would improve gait mechanics when quantified by net lower limb joint work across the stance phase of walking. We performed gait analyses in 35 patients with PAD and 35 healthy, older adults. Patients with PAD performed a walking protocol prior to and six months following revascularization surgery. Healthy adults only took part in a single walking session. Lower limb joint powers were calculated using inverse dynamics and were integrated across early, middle, and late stance phases to determine the work performed during each phase (J kg-1). The work mechanical ratio between positive-producing and negative-producing phases of stance was calculated for each lower-limb joint. Self-selected walking speed significantly increased from 1.13 ± 0.2 ms-1 to 1.26 ± 0.18 ms-1 in patients following revascularization (p < 0.001). We observed a significant decrease in positive late stance work (p < 0.001) in conjunction with more negative work during early stance (p < 0.001) in patients following revascularization. Revascularization surgery led to faster walking without an increase in the ankle joint's mechanical ratio. Our results suggest faster walking was achieved via work done at the hip rather than the ankle. These findings suggest that additional therapies that facilitate the restoration of muscle, tissue, and nervous system damage caused by years of having reduced blood flow to the limbs might still be beneficial following revascularization.

Examining Race and Patient-Reported Outcomes After Contralateral Prophylactic Mastectomy with Reconstruction.

BACKGROUND: Little is known regarding racial differences in satisfaction and quality of life (QOL) after contralateral prophylactic mastectomy (CPM). In this study, we aim to characterize associations between race, and postoperative satisfaction and well-being, utilizing the validated BREAST-Q patient-reported outcome measure. PATIENTS AND METHODS: Patients were eligible if they were diagnosed with stage 0-III unilateral breast cancer and underwent mastectomy with immediate reconstruction at our institution between 2016 and 2022. BREAST-Q surveys were administered in routine clinical care preoperatively and postoperatively to assess QOL. We assessed whether the relationship between race, and domains of satisfaction with breasts and psychosocial well-being differed by receipt of CPM compared with unilateral mastectomy at 6 months, 1 year, 2 years, and 3 years following reconstruction. RESULTS: Of 3334 women, 2040 (61%) underwent unilateral mastectomy and 1294 (39%) underwent CPM. Compared with White and Asian women who received CPM, Black women who underwent CPM were more likely to have higher BMI (p < 0.001), undergo autologous reconstruction (p = 0.006), and receive postmastectomy radiation (PMRT) (p < 0.001). There was no association between race and domains of satisfaction of breasts or psychosocial well-being for women who underwent unilateral mastectomy (p = 0.6 and p > 0.9, respectively) or CPM (p = 0.8 and p = 0.9, respectively). PMRT was negatively associated with both satisfaction with breasts (p < 0.001) and psychosocial well-being (p = 0.007). CONCLUSIONS: Differences in satisfaction with breasts and psychosocial well-being at 3-year follow-up were not associated with race but rather treatment variables, particularly the receipt of PMRT. Further investigations with a larger and more diverse population are needed to validate these findings.

Mutational Status is Associated with a Higher Rate of Pathologic Complete Response After Neoadjuvant Chemotherapy in Hormone Receptor-Positive Breast Cancer.

BACKGROUND: Pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) occurs in up to 20% of hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancers. Whether this differs among BRCA mutation carriers is uncertain. This study compared pCR between BRCA1/2 mutation carriers and matched sporadic control subjects. METHODS: From November 2013 to January 2022, this study identified 522 consecutive women with clinical stage I to III HR+/HER2- breast cancer treated with NAC and surgery. The study matched BRCA1/2 mutation carriers 1:2 to non-carriers in terms of age, clinical tumor (cT) and nodal (cN) stage, and differentiation. Two-sample non-parametric tests compared baseline characteristics. Multivariable logistic regression assessed pCR (i.e., ypT0/ispN0) by BRCA1/2 mutational status. RESULTS: Of the 522 women (median age, 50 years), 59 had BRCA1/2 mutations, 78% of which were clinically node positive. Anthracycline-based NAC was administered to 97%. More BRCA1/2 mutation carriers were younger, had cT1 tumors, and had poorly differentiated disease. After matching, 58 BRCA1/2 mutation carriers were similar to 116 non-carriers in terms of age (p = 0.6), cT (p = 0.9), cN stage (p = 0.7), and tumor differentiation (p > 0.9). Among the mutation carriers, the pCR rate was 15.5% for BRCA1/2, 38% (8/21) for BRCA1, and 2.7% (1/37) for BRCA2 versus 7.8% (9/116) for the non-carriers (p < 0.001). After NAC, 5 (41.7%) of the 12 BRCA1 mutation carriers converted to pN0 versus 10 (37%) of the 27 BRCA2 mutation carriers and 19 (20.9%) of the 91 non-carriers (p = 0.3). In the multivariable analysis, BRCA1 mutation status was associated with higher odds of pCR than non-carrier status (odds ratio [OR] 6.31; 95% confidence interval [CI] 1.95-20.5; p = 0.002), whereas BRCA2 mutation status was not (OR 0.45; 95% CI 0.02-2.67; p = 0.5). CONCLUSIONS: This study showed that BRCA1 mutation carriers with HR+/HER2- breast cancers have a higher rate of pCR than sporadic cancers and may derive greater benefit from chemotherapy. The use of NAC to downstage these patients should be considered.

Satisfaction and Well-Being After Contralateral Prophylactic Mastectomy Among BRCA Mutation Carriers and Noncarriers: A Longitudinal Analysis of BREAST-Q Domains.

INTRODUCTION: Contralateral prophylactic mastectomy (CPM) is recommended for BRCA mutation carriers; its use in noncarriers relies on patient choice. We characterized differences in satisfaction and well-being after CPM between BRCA carriers and noncarriers. METHODS: BREAST-Q data were obtained before and after CPM with immediate reconstruction performed at a single institution from 2016 to 2022. Associations between BRCA status and satisfaction with breasts, psychosocial well-being, and sexual well-being were assessed, with adjustment for preoperative scores and relevant confounders. RESULTS: In total, 149 BRCA carriers and 842 noncarriers were included. Response rates varied over time (preoperative, 56%; 6 months, 78%; 1 year, 51%; 2 years, 52%; 3 years, 59%). BRCA carriers were younger (p < 0.001), with a higher rate of neoadjuvant chemotherapy (p < 0.001). More noncarriers had HR+/HER2- tumors (p < 0.001) and underwent endocrine therapy (p < 0.001). Baseline satisfaction with breasts was higher among BRCA carriers (median [interquartile range] score, 70 [53-82] vs. 58 [48-70]; p = 0.006); psychosocial (p = 0.20) and sexual (p = 0.14) well-being were not significantly different between groups. BRCA carriers had a greater decrease in satisfaction with breasts (p = 0.04) and psychological well-being (p = 0.05) from baseline to 6 months; decrease in sexual well-being (p = 0.38) was not significantly different between groups. On univariate and multivariable analyses, BRCA status was not associated with satisfaction with breasts, sexual well-being, or psychosocial well-being. CONCLUSIONS: Satisfaction and well-being were similar between BRCA carriers and noncarriers treated with CPM. Relative to noncarriers, BRCA carriers experienced a greater decline in satisfaction with breasts and psychological well-being at 6 months after CPM.

Impact of holistic review on diversity of interviewed and matriculating residents in graduate medical education: a systematic review protocol.

INTRODUCTION: Diversity in the physician workforce improves patient-centred outcomes. Patients are more likely to trust in and comply with care when seeing gender/racially concordant providers. A current emphasis on standardised metrics in academic achievement often serves as a barrier to the recruitment and retention of gender and racial minorities in medicine. Holistic review of residency applicants has been supported as a means of encouraging diversification but is not yet standardised. The current body of evidence examining the effects of holistic review on the recruitment of racial and gender minorities in surgical residencies is small. We therefore propose a systematic review to summarise the state of holistic review in graduate medical education in the USA and its impact on diversification. METHODS AND ANALYSIS: Our systematic review protocol has been designed with plans to report our review findings in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. PubMed and Embase will be searched with the assistance of a health sciences librarian with expertise in systematic review. We will include studies of graduate medical education programmes that describe the implementation of holistic review, outline the components of their holistic review process and compare proportions of under-represented minorities (URM) and women interviewed and matriculating before and after holistic review implementation. We will first report a summary of the findings regarding the operationalisation of holistic review as described by studies included. We will then pool the percentages of URM and women for interviewee and matriculant populations from each study and report the collective odds ratios of each for holistic review compared with traditional review as our primary outcome. ETHICS AND DISSEMINATION: This study is a protocol for systematic review, and therefore does not involve any human subjects. Findings will be published in the form of a manuscript submitted to a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42023401389.

Long-term use of an ankle-foot orthosis intervention in patients with peripheral artery disease using the integrated promoting action on research implementation in health services (i-PARIHS) framework.

BACKGROUND: Peripheral artery disease (PAD) is a cardiovascular disease that limits patients' walking ability. Persistent ankle-foot orthosis (AFO) use may increase the distance patients can walk as well as physical activity. PURPOSE: The purpose of the study was to determine the implementation and patients' perspectives related to the use or disuse of the AFO intervention six months post-intervention. This study was guided by a semi-structured interview and survey based on the integrated Promoting Action on Research Implementation in Health Services (i-PARIHS) constructs. DESIGN: A convergent mixed methods design was used to evaluate participants' perceptions six months following a three-month AFO intervention. A survey and semi-structured questionnaire based on the i-PARIHS constructs were administered and analyzed. SETTING: Vascular surgery clinic and biomechanics research laboratory. PARTICIPANTS: Patients (N = 7; male, 100%; age, 71.9 ± 0.6.7y; body mass index, 29.0 ± 0.5.5; ankle brachial index 0.50 ± 0.17) with claudication completed the study. INTERVENTIONS: A certified orthotist fit participants with an AFO that was worn for 3 months. MAIN OUTCOME MEASURES: Qualitative analysis of semi-structured interviews and quantitative analysis of the survey. RESULTS: The highest positive ratings were seen in the dimensions of usability and cost-effectiveness. The patients found the AFO device and instructions to wear, easy when starting the intervention and there were no out-of-pocket costs. The lower scores and challenges faced with observability and relative advantage domains indicated issues related to motivation for sustained use of the AFO. CONCLUSIONS: Barriers associated with AFO function that prevent common activities and poor health seem to be the biggest issue for not wanting to wear the AFO after the 3-month intervention. Addressing patients' perceptions and challenges to wearing the AFO is essential to increasing compliance and physical activity. Future research should concentrate on understanding the compatibility of orthotic device interventions with the subject's lifestyle. CLINICAL TRIAL REGISTRATION NO: NCT02902211.

Outcomes of a pilot virtual mentorship program for medical students interested in surgery.

BACKGROUND: Lack of mentorship may deter medical students who identify as underrepresented minorities (URM) from entering academic surgery. METHODS: 30 mentor-medical student pairs from the AWS 2020 virtual mentorship pilot-program were surveyed pre-and post-program to explore 1) feasibility of meetings, and, 2) program's perceived efficacy in fostering professional development skills. Participants responded using a 5-point Likert scale (1 = not at all; 5 = completely). Proportions of participants in each category were compared. RESULTS: Proportion of participants perceiving monthly meetings to be completely feasible did not differ from pre-to post-program surveys for mentees (75%(21/28) vs. 71%(12/17); p = 0.743) or mentors (71%(17/24) vs 71%(13/18); p = 1.00). Compared to pre-program responses, mentees endorsed "completely" (Likert scale 5) improving with regard to their elevator speech (p = 0.001), developing their curriculum vitae (p = 0.003), ability to network (p = 0.021), and acquiring skills for career advancement (p = 0.003). CONCLUSION: Virtual mentorship may be a feasible and effective means of increasing access to mentors for URM medical students.

Exploring Characteristics of Academic General Surgery Residency Applicants: A Group Concept-Mapping Approach.

OBJECTIVE: Holistic review, which emphasizes qualitative attributes over objective measures, has been proposed as a method for selecting candidates for surgical residency in order to improve diversity in graduate medical education, and, ultimately, the field of surgery. This study seeks to articulate desirable traits of applicants as a first-step in standardizing the holistic review process. DESIGN: Using Group Concept Mapping, a web-based mixed-methods participatory research methodology, residency selection committee members were asked to 1) list desirable characteristics of applicants, 2) group these into categories, 3) rate their importance to academic/clinical success on a 5-point Likert scale (1 = not at all important, 5 = extremely important), and 4) rate the degree to which each characteristic is feasible to assess on a 3-point Likert scale (1 = not at all feasible, 3 = very feasible). Grouped characteristics submitted to hierarchical cluster analysis depicted committee's consensus about desirable qualities/criteria for applicants. Bivariate scatter-plots and pattern-matching graphics demonstrated which of these criteria were most important and reliably assessed. SETTING: A single academic general surgery residency training program in Western Pennsylvania. PARTICIPANTS: Members of the selection committee for the UPMC General Surgery Residency program who had participated in at least 1 prior cycle of applicant selection. RESULTS: Desirable characteristics of highly qualified applicants into an academic general surgery residency were clustered into domains of 1) scholarly work and research, 2) grades/formal assessments, 3) program fit, 4) behavioral assets, and 5) aspiration. Behavioral assets, which was felt to be the most important to clinical and academic success were considered to be the least feasible to reliably assess. Within this domain, initiative, being self-motivated, intellectual curiosity, work ethic, communication skills, maturity and self-awareness, and thoughtfulness were viewed as most frequently reliably assessed from the application and interview process. CONCLUSIONS: High quality applicants possess several behavioral assets that faculty deem are important to academic and clinical success. Adapting validated metrics for assessing these assets, may provide a solution for addressing subjectivity and other challenges scrutinized by critics of holistic review.

Cost-effectiveness of Choosing Wisely guidelines for axillary observation in women older than age 70 years with hormone receptor-positive, clinically node-negative, operable breast tumors.

BACKGROUND: The Society for Surgical Oncology's Choosing Wisely guidelines recommend against sentinel lymph node biopsy (SLNB) in favor of observation in this population. Recent analyses reveal that this has not been widely adopted. The purpose of this cost-effectiveness analysis is to compare the costs and benefits associated with observation or SLNB in women >70 years old with hormone receptor-positive, clinically node-negative, operable breast cancer. METHODS: A decision tree with Markov modeling was created to compare treatment strategies using long-term follow-up data from clinical trials in this population. Costs were estimated from published literature and publicly available databases. Breast cancer-specific health-state utilities were derived from the literature and expert opinion. One-way, 2-way, and probabilistic sensitivity analyses were conducted. A structural sensitivity analysis was performed to assess the effect of functional status and anxiety from nonevaluation of the axilla on cost-effectiveness. Costs and benefits, measured in life-years (LYs) and quality-adjusted life-years (QALYs), were tabulated across 10, 15, and 20 years and compared using incremental cost-effectiveness ratios (ICERs). RESULTS: SLNB is not cost-effective from the payer or societal perspectives with ICERs of $138,374/LY and $131,900/LY, respectively. When QALYs were considered, SLNB provided fewer QALYs (SLNB, 10.33 QALYs; observation, 10.53 QALYs) at a higher cost (SLNB, $15,845; observation, $4020). Structural sensitivity analysis revealed that SLNB was cost-effective in certain patients with significant anxiety related to axillary observation (ICER, $39,417/QALY). CONCLUSIONS: Routine SLNB in this population is not cost-effective. The cost-effectiveness of SLNB, however, is dependent on individual patient factors, including functional status as well as patient preference.

Investigation into the Cost-Effectiveness of Extended Posttraumatic Thromboprophylaxis.

BACKGROUND: Severely injured patients are at particularly high risk for venous thromboembolism (VTE). Although thromboprophylaxis (PPX) is employed during the inpatient period, patients may continue to be at high risk after discharge. Comparative evidence from surgical subspecialities (eg oncology) reveals benefits of postdischarge (ie extended) PPX. We hypothesized that an extended, postinjury oral thromboprophylaxis regimen would be cost-effective. STUDY DESIGN: A cost-utility model compared no PPX with a 30-day course of apixaban, dabigatran, enoxaparin, fondaparinux, or rivaroxaban in trauma patients. Immediate events including deep venous thrombosis, pulmonary embolus, or bleeding within 30 days of injury were modeled in a decision tree with patients entering a Markov process to account for sequelae of VTE, including postthrombotic syndrome and chronic thromboembolic pulmonary hypertension. Effectiveness was measured in quality-adjusted life years. One-way and probabilistic sensitivity analyses were performed to identify conditions under which the preferred PPX strategy changed. RESULTS: Rivaroxaban was the dominant strategy (ie less costly and more effective) compared with no PPX or alternative regimens, delivering 30.21 quality-adjusted life years for $404,546.38. One-way sensitivity analyses demonstrated robust preference for rivaroxaban. When examining only patients with moderate-high or high VTE Risk Assessment Profile scores, rivaroxaban remained the preferred strategy. Probabilistic sensitivity analysis demonstrated a preference for rivaroxaban in 100% of cases at a standard willingness-to-pay threshold of $100,000/quality-adjusted life year. CONCLUSIONS: A 30-day course of rivaroxaban is a cost-effective extended thromboprophylaxis strategy in trauma patients in this theoretical study. Prospective studies of postdischarge thromboprophylaxis to prevent postinjury VTE are warranted.

Patient Perceptions of Changes in Breast Cancer Care and Well-Being During COVID-19: A Mixed Methods Study.

BACKGROUND: Widespread healthcare restructuring due to the COVID-19 pandemic led to modifications in the timing and delivery of care for breast cancer patients. Our study explores patient concerns relating to COVID-19, breast cancer, and changes to breast cancer care. PATIENTS AND METHODS: Breast cancer patients who presented for surgical consultation at an academic, multidisciplinary clinic completed the electronically distributed validated COVID-19 Impact and Healthcare Related Quality of Life questionnaire between August 2020 and February 2021. This questionnaire uses Likert score responses to assess COVID-specific concerns within domains, including distress and financial hardship. Scale scores were determined by averaging items within each domain, and scores > 2 indicated greater disruption. Semistructured interviews were conducted with patients who indicated interest in participating in the questionnaire. RESULTS: Of 381 patients recruited, 133 patients completed the questionnaire and 20 patients completed interviews. Sixty-three percent of survey participants reported attending a telemedicine appointment for their cancer care, and the majority (67%) were satisfied with their experience. Half of the participants (50%) reported fear about how the COVID-19 pandemic will impact their cancer care or recovery, and 66% reported anxiety about contracting COVID-19. Twenty-two percent of participants reported decreased income due to COVID-19. Patient interviews revealed tangible changes to care and provided in-depth information on the advantages and disadvantages of telehealth. CONCLUSIONS: Breast cancer patients report anxiety about COVID-19 infection and potential care modifications. Our study identifies impacts on patients' care and quality of life. Further investigation will inform interventions to improve psychosocial outcomes for patients and the telehealth experience.

Claudicating patients with peripheral artery disease have meaningful improvement in walking speed after supervised exercise therapy.

OBJECTIVE: Supervised exercise therapy (SET) is a first-line treatment for patients with peripheral artery disease (PAD). The efficacy of SET is most commonly expressed by significant statistical improvement of parameters that do not clarify how each individual patient will benefit from SET. This study examined the minimal clinically important difference (MCID) in walking speed in claudicating patients with PAD after SET. METHODS: A total of 63 patients with PAD-related claudication (Fontaine stage II PAD) participated in a 6-month SET program. Self-selected walking speed was measured before and after SET. Distribution and anchor-based approaches were used to estimate the MCID for small and substantial improvement. The ability to walk one block and the ability to climb one flight of stairs questions were chosen as anchor questions from the Medical Outcomes Study 36-item Short Form questionnaire. Receiver operating characteristics curve analyses were performed to detect the threshold for MCID in walking speed after treatment. RESULTS: The distribution-based method estimated 0.03 m/s as a small improvement and 0.08 m/s as a substantial improvement after SET. Small and substantial improvements according to the anchor question walking one block were 0.05 m/s and 0.15 m/s, respectively. For the climbing one flight of stairs anchor question, 0.10 m/s was a small improvement. Receiver operating characteristics curve analyses identified an increase of 0.04 m/s and 0.03 m/s for improvement based on walking one block and climbing one flight of stairs, respectively. CONCLUSIONS: We report our findings for the MCID for walking speed among claudicating patients receiving SET. Claudicating patients who increase walking speed of 0.03 m/s or greater are more likely to experience a meaningful improvement in walking impairment than those who do not. The MCID reported in this study can serve as a benchmark for clinicians to develop goals and interpret clinically meaningful progress in the care of claudicating patients with PAD.

Association of Tumor Molecular Subtype and Stage with Breast and Axillary Pathologic Complete Response After Neoadjuvant Chemotherapy for Breast Cancer.

BACKGROUND: Axillary pathologic complete response (pCR) confers higher overall and recurrence-free survival than residual axillary disease. Although breast pCR (ypT0) is associated with a pathologically negative axilla (ypN0) in human epidermal growth factor receptor 2-positive (HER2+) and triple-negative breast cancer (TNBC), how clinical T (cT) and N (cN) staging are associated with ypN0 in other tumor subtypes is incompletely understood. METHODS: A single-institution cancer registry was retrospectively reviewed for patients receiving neoadjuvant chemotherapy (NAC) followed by surgery from 2010 to 2018. Fisher's exact tests compared proportion of breast and axillary pCR by tumor subtype (hormone receptor [HR]-positive /HER2-,HR+/HER2+,HR-/HER2+,HR-/HER2-). Logistic regression determined factors associated with ypN0. Sensitivity analyses determined how cN status affected ypN status by tumor subtype. RESULTS: The study enrolled 1348 patients. The median age was 54 years (interquartile range [IQR], 44-63 years), and 55% of the patients (n = 736) were postmenopausal. The tumor subtypes were HR+/HER2- (12%, n = 155), HR+/HER2+ (48%, n = 653), HR-/HER2+ (25%, n = 343), and TNBC (15%, n = 197). In the study, cT included T0 (1%, n = 18), T1 (20%, n = 272), T2 (53%, n = 713), T3 (17%, n = 230), and T4 (9%, n = 111), and cN included cN0 (51%, n = 687), cN1 (41%, n = 549), cN2 (5%, n = 61), and cN3 (3%, n = 43). Breast pCR and ypN0 occurred most in the HER2+ and TNBC subtypes. A negative association was found between ypN0 and age at diagnosis (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.97-0.99; p < 0.001), cT4 stage (OR, 0.29; 95% CI, 0.09-0.91; p = 0.034), and HR+ subtypes (HR+/HER2-: OR, 0.54; 95% CI, 0.31-0.94; p = 0.028; HR+/HER2+: OR, 0.60; 95% CI, 0.39-0.93; p = 0.024). The HR-/HER2+ subtype was associated with ypN0 (OR, 1.70; 95% CI, 1.05-2.73; p = 0.030), and cN2/cN3 was negatively associated with ypN0 in HR+/HER2+ disease (OR, 0.26; 95% CI, 0.11-0.61; p = 0.002), HR-/HER2+ disease (OR, 0.42; 95% CI, 0.22-0.77; p = 0.005), and TNBC (OR, 0.11; 95% CI, 0.03-0.40; p = 0.001). CONCLUSION: Tumor subtype, clinical stage, and age at diagnosis may be important in consideration of de-escalation of axillary staging.