Factors Predictive of Positive Lymph Nodes for Breast Cancer.

BACKGROUND: Axillary node status is an important prognostic factor in breast cancer. The primary aim was to evaluate tumor size and other characteristics relative to axillary disease. MATERIALS AND METHODS: Single institution retrospective chart review of stage I-III breast cancer patients collected demographic and clinical/pathologic data from 1998-2019. Student's t-test, Chi-squared test (or Fisher exact test if applicable), and logistic regression models were used for testing the association of pN+ to predictive variables. RESULTS: Of 728 patients (mean age 59 yrs) with mean follow up of 50 months, 86% were estrogen receptor +, 10% Her2+, 78% ER+HER2-negative, and 10% triple-negative. In total, 351/728 (48.2%) were pN+ and mean tumor size was larger in pN+ cases compared to pN- cases (mean = 27.7 mm versus 15.5 mm) (p < 0.001). By univariate analysis, pN+ was associated with lymphovascular invasion (LVI), higher grade, Her2, and histology (p < 0.005). Tumor-to-nipple distance was shorter in pN+ compared to pN- (45 mm v. 62 mm; p< 0.001). Age < 60, LVI, recurrence, mastectomy, larger tumor size, and shorter tumor-nipple distance were associated with 3+ positive nodes (p < 0.05). CONCLUSIONS: Larger tumor size and shorter tumor-nipple distance were associated with higher lymph node positivity. Age less than 60, LVI, recurrence, mastectomy, larger tumor size, and shorter tumor-nipple distance were all associated with 3+ positive lymph nodes.

Retrospective Study of Treatment Patterns and Natural History of Patients with T1a/b N0 Triple-Negative Breast Cancers: A Single-Institution Experience.

INTRODUCTION: T1a/b, node-negative (node-), triple-negative breast cancers (TNBCs) are underrepresented in randomized drug-approving clinical trials. Given their low incidence, the clinicopathological features, natural history, and treatment patterns of these tumors remain insufficiently understood. METHODS: We conducted a single-institution retrospective cohort study of patients with T1a/b, N0, M0 TNBCs. Deidentified patient- and tumor-related data were collected and summarized. Kruskal-Wallis, χ2, or Fisher exact tests were used to evaluate associations of interest. Kaplan-Meier methods, log-rank tests, and Cox's proportional hazards models were applied for survival analyses. RESULTS: Of 108 cases of node- TNBCs measuring ≤2 cm, 34 node- T1a/b tumors were included in our analysis. All cases had an intermediate to high histological grade, and most had a Ki-67 score of ≥20%. All patients received adjuvant chemotherapy, and many underwent mastectomy (47%). Docetaxel combined with cyclophosphamide was the most common adjuvant chemotherapy regimen (75%). We did not observe significant associations between improved outcomes and treatment with anthracycline-containing regimens. Among patients with node- pT1a/b tumors, the estimated 3-year recurrence-free survival (RFS) and distant RFS rates were both 96.3% (95% CI: 76.5-99.5), and the overall survival rate was estimated to be 100% (95% CI: 100-100). There were no cases of local recurrences observed. CONCLUSIONS: In our cohort, all patients with T1a/b node- TNBCs were treated with adjuvant chemotherapy and had favorable outcomes even when treated with anthracycline-sparing regimens.

Surgical Management of the Axilla in HR+/HER2- Breast Cancer in the Z1071 Era: A Propensity Score-Matched Analysis of the National Cancer Database.

BACKGROUND: Axillary management varies between sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) for patients with clinical N1 (cN1), hormone receptor-positive (HR+), human epidermal growth factor receptor 2 (HER2)/neu-negative (HER2-), infiltrative ductal carcinoma (IDC) who achieve a complete clinical response (cCR) to neoadjuvant systemic therapy (NAST). This study sought to evaluate clinical practice patterns and survival outcomes of SLNB versus ALND in this patient subset. METHODS: Patients with cN1, HR+/HER2-, unilateral IDC demonstrating a cCR to NAST were identified from the 2012-2017 National Cancer Database (NCDB) and stratified based on final axillary surgery management (SLNB vs ALND). After propensity score-matching, overall survival (OS) was compared using a Kaplan-Meier analysis, and significant OS predictors were identified using Cox regression. RESULTS: Of the 1676 patients selected for this study, 593 (35.4%) underwent SLNB and 1083 (64.6%) underwent ALND. Use of SLNB increased by 28 % between 2012 and 2017. Among a total of 584 matched patients, 461 matched ypN0 patients, and 108 matched ypN+ patients, mean OS did not differ between SLNB and ALND (all patients [92.1 ± 0.8 vs 90.2 ± 1.0 months; p = 0.157], ypN0 patients [92.4 ± 0.8 vs 89.9 ± 0.9 months; p = 0.105], ypN+ patients [83.5 ± 2.3 vs 91.7 ± 2.7 months; p ± 0.963). Cox regression identified age, Charlson score, clinical T stage, and pathologic nodal status as significant predictors of OS. CONCLUSION: The final surgical management strategy used for cN1, HR+/HER2- IDC patients who achieved a cCR to NAST did not have a significant impact on survival outcomes in this analysis. Potential opportunities for de-escalation of axillary management among this patient subset exist, and validation studies are needed.

Surgeon and Radiologist Evaluation of Electromagnetic Chip Localization for Benign and Malignant Breast Lesions.

BACKGROUND: SmartClipTM is a food and drug administration-approved, electromagnetic chip (EMC) localization system that provides three-dimensional navigation for the excision of soft tissue lesions. The purpose of this study was to analyze the accuracy and feasibility of EMC radiologic and surgical localization for benign and malignant breast lesions. PATIENTS AND METHODS: An institutional review board-approved, single institution, prospective study from October 2020 to September 2022 of 38 women undergoing breast conserving surgery with EMC localization of a single lesion > 5 mm on mammogram (MMG) or ultrasound (US) imaging. Surveys from performing breast radiologists and breast surgeons were collected after image-guided localization and surgical excision. RESULTS: Seventy-six survey responses from nine radiologists and four surgeons were received. The deployment needle and EMC were highly visible in 86.8% and 76.3% of procedures, respectively. There was no difficulty in deployment for 92.1% of procedures. The EMC was in the correct location on postdeployment MMG in 97.4% of cases. Three instances of EMC migration occurred, one 1 cm from target lesion. The targeted mass and EMC were within the surgical specimen in 97.4% of cases. On specimen radiograph, 39.5% of the EMCs were 0-1 mm from the center of the target lesion, 18.4% were within 2-4 mm, and 23.7% were within 5-10 mm. Mean operating room time for all cases was 65 min. One case required US to localize the target due to console malfunction. CONCLUSION: There was successful EMC deployment by radiologists with accurate visualization and successful surgical excision in most cases. The EnVisioTM SmartClipTM system is a reproducible and accurate localization method for benign and malignant breast lesions.

Oncolytic T-VEC virotherapy plus neoadjuvant chemotherapy in nonmetastatic triple-negative breast cancer: a phase 2 trial.

Talimogene laherparepvec (T-VEC) is an oncolytic virus hypothesized to enhance triple-negative breast cancer (TNBC) responses to neoadjuvant chemotherapy (NAC). This article describes the phase 2 trial of T-VEC plus NAC (ClinicalTrials.gov ID: NCT02779855 ). Patients with stage 2-3 TNBC received five intratumoral T-VEC injections with paclitaxel followed by doxorubicin and cyclophosphamide and surgery to assess residual cancer burden index (RCB). The primary end point was RCB0 rate. Secondary end points were RCB0-1 rate, recurrence rate, toxicity and immune correlates. Thirty-seven patients were evaluated. Common T-VEC toxicities were fevers, chills, headache, fatigue and injection site pain. NAC toxicities were as expected. Four thromboembolic events occurred. The primary end point was met with an estimated RCB0 rate = 45.9% and RCB0-1 descriptive rate = 65%. The 2-year disease-free rate is equal to 89% with no recurrences in RCB0-1 patients. Immune activation during treatment correlated with response. T-VEC plus NAC in TNBC may increase RCB0-1 rates. These results support continued investigation of T-VEC plus NAC for TNBC.

Breast Surgical Oncology Fellowship applicant selection and ranking: A survey of Society of Surgical Oncology programs.

BACKGROUND AND OBJECTIVES: In 2003, the Society of Surgical Oncology (SSO) initiated a breast surgical oncology fellowship, which has now grown to 60 SSO accredited programs as of 2021. Limited knowledge exists on the traits of successful applicants and the factors influencing the rank list. METHODS: A web-based, anonymous survey was sent to all SSO Breast Surgical Oncology Fellowship program directors. The survey consisted of 26 questions. Descriptive statistics were used to analyze survey responses and evaluate impact on applicant interview and rank list. RESULTS: Thirty-four programs (57% response rate) completed the survey. Programs received an average of 70 applications and granted 24 interviews. Most programs reported a minimum ABSITE cut-off score (n = 28, 82%) and a defined publication requirement (n = 22, 65%), including a first-author requirement (n = 18, 53%) to extend an invitation to interview. For postinterview rank, applicant interpersonal skills were highly valued. The interview was the most important aspect for the rank list. CONCLUSIONS: Many programs have ABSITE and publication thresholds before offering an interview. Upon receiving interview invitation, the applicant's interview performance, interpersonal skills, and letters of recommendation were the most important aspect in rank list decision making.

Surgical Management of the Axilla in Invasive Lobular Carcinoma in the Z1071 Era: A Propensity-Score Matched Analysis of the National Cancer Database.

In patients with invasive lobular carcinoma (ILC) and clinically positive nodes (cN1) who demonstrate an axillary clinical response to neoadjuvant-chemotherapy (NAC), the outcomes of sentinel lymph node biopsy (SLNB) compared to axillary lymph node dissection (ALND) are not well studied. We sought to evaluate axillary surgery practice patterns and the resultant impact on overall survival (OS) in cN1 ILC. The National Cancer Database (NCDB) was queried (2012-2017) for women with cN1 ILC who were treated with NAC followed by surgery. Propensity-score matching was performed between SLNB and ALND cohorts. Kaplan-Meier and Cox regression analyses were performed to identify predictors of OS. Of 1390 patients, 1192 were luminal A ILCs (85.8%). 143 patients (10.3%) had a complete axillary clinical response, while 1247 (89.7%) had a partial clinical response in the axilla. Definitive axillary surgery was SLNB in 211 patients (15.2%). Utilization of SLNB for definitive axillary management increased from 8% to 16% during the study period. Among 201 propensity-score matched patients stratified by SLNB vs. ALND, mean OS did not significantly differ (81.6 ± 1.8 vs. 81.4 ± 2.0 months; p = 0.56). Cox regression analysis of the entire cohort demonstrated that increasing age, grade, HER2+ and triple-negative tumors, and partial clinical response were unfavorable OS predictors (p < 0.02 each). The definitive axillary operation and administration of adjuvant axillary radiation did not influence OS. In cN1 ILC patients with a clinical response to NAC in the axilla, SLNB vs. ALND did not affect OS. Further axillary therapy may be warranted with ypN+ disease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody prevalence in a healthcare worker population exceeded self-reported infection rates, 2020.

A study of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) seroprevalence at a healthcare institution prior to the availability of vaccine showed that seroprevalence in the cohort increased over 6 months from 25% to 55%. The number of employees with antibodies was higher than the number who reported an exposure or diagnosis at each time point.

Effect of Microporous Polysaccharide Particles in Patients Undergoing Mastectomy.

BACKGROUND: Microporous polysaccharide particles (MPP, proprietary name "Arista AH"), derived from purified plant starch, are used to augment hemostasis at surgery. The effect of MPP regarding short-term complications after mastectomy remains an area of ongoing investigation. PATIENTS AND METHODS: A single-institution, retrospective chart review of patients undergoing unilateral mastectomy without reconstruction from January 2019 to 2021 was performed. Primary endpoints included antibiotic prescription, seroma or abscess drainage, readmission, wound dehiscence, and time to drain removal within 30 days of initial surgery. Wilcoxon rank sum test or Student t test was used for group comparisons for continuous variables; Chi-square test or Fisher exact test was used to evaluate the associations among categorical variables. RESULTS: One hundred ninety patients were included; 119 received MPP and 71 did not. There was no difference in antibiotic prescription, infection drainage, hematoma, readmission, dehiscence, or time to drain removal with regards to MPP use. MPP treated patients were older (65.8 years vs. 59.1, P < .001) and had lower albumin levels (4.1 g/dL vs. 4.3, P = .025). Patients who underwent abscess drainage had higher body mass index ( mean 36.1 vs. 30.1 P = .036). Patients requiring seroma drainage were more likely to be diabetic (12.8% vs. 4%, P = .035) and to have been treated with lymphovenous anastomosis (LVA, 15.6% vs. 3.8%, P = .009). Patients who had LVA were significantly less likely to receive MPP when compared to other groups (3.1% vs. 74.7% P < .001). CONCLUSION: Consider utilizing MPP in patients at higher risk of seroma, such as those undergoing axillary surgery including LVA.

Surgical Management of Axilla of Triple-Negative Breast Cancer in the Z1071 Era: A Propensity Score-Matched Analysis of the National Cancer Database.

BACKGROUND: The role of sentinel lymph node biopsy (SLNB) in triple-negative breast cancer (TNBC) patients who present with clinical N1 (cN1) disease and undergo complete clinical response (cCR) to neoadjuvant systemic therapy (NAST) remains unclear. We aimed to study the outcomes of SLNB versus axillary lymph node dissection (ALND) in this setting. PATIENTS AND METHODS: Patients with cN1 TNBC who showed cCR to NAST were selected from the National Cancer Database (NCDB), and propensity score matched 1:1 between SLNB and ALND in all-comers, ypN0, and ypN1 subgroups. Overall survival (OS) was compared using the Kaplan-Meier method. Cox regression was used to identify predictors of OS. RESULTS: Of the 2953 patients selected. 1062 (36.0%) underwent SLNB and 1891 (64.0%) underwent ALND. There was a chronological increase in national SLNB utilization (from 20% in 2012 to 46% in 2017). One thousand three patients were propensity matched between SLNB and ALND, and no OS difference was noted (81.73 ± 1.04 vs. 80.07 ± 0.70 months; p = 0.127). In the ypN0 subgroup, 884 pairs were matched and no significant OS difference was found (85.29 ± 0.84 vs. 82.60 ± 0.68 months; p = 0.638). In ypN+ patients, 129 pairs were matched and demonstrated a trend toward decreased OS with SLNB (64.37 ± 3.12 vs. 72.45 ± 72.45; p = 0.085). Cox regression identified age, inner tumors, advanced T stage, partial/no in-breast response, and nodal status as unfavorable predictors of OS. Definitive axillary surgical procedure was not a predictor in the final model. CONCLUSION: SLNB and ALND appear to yield comparable OS in cN1 TNBC patients who demonstrate cCR to NAST. Caution should be exercised in ypN1 patients as worse OS could be associated with SLNB.

Real-world benefit of combination palbociclib and endocrine therapy for metastatic breast cancer and correlation with neutropenia.

BACKGROUND: Combination CDK4/6 inhibitor and endocrine therapy has been shown to significantly improve progression-free survival (PFS) in patients with hormone receptor (HR)-positive, HER2-negative metastatic breast cancer (mBC). The aim of this retrospective study was to evaluate the real-world benefit of first-line combination therapy in this cohort and to correlate treatment efficacy with neutropenia, a common toxicity of CDK4/6 inhibitors. METHODS: This study included HR-positive, HER2-negative advanced or mBC patients who were treated with palbociclib plus endocrine therapy, mainly letrozole, between 1 January 2015 and 1 March 2018. Progression-free survival (PFS) was determined using Kaplan-Meier analysis. The predictive value of absolute neutrophil count (ANC) and neutrophil-to-lymphocyte ratio (NLR) for PFS were explored using Cox regression models. Both ANC and NLR were used as a time-dependent variable. RESULTS: In total, 165 patients were included with median PFS of 24.19 months (95% CI 18.93-NR). Median PFS for patients with bone-only metastases (n = 54) was not reached (95% CI 18.21-NR). Among patients with all other metastases (n = 111), median PFS was 24.19 months (95% CI 16.33-33.82). Lower ANC was correlated with decreased risk of progression (HR 0.84, 95% CI 0.71-0.97, p = 0.008). There was no significant association between NLR and the risk of disease progression (HR 1.07, 95% CI 0.97-1.18, p = 0.203). CONCLUSION: The effectiveness of palbociclib and endocrine therapy in the treatment of HR-positive, HER2-negative mBC in the real-world setting is similar to the efficacy reported in the PALOMA-2 trial. Patients with lower neutrophil count may have a lower risk of early disease progression.

Surgical Management of the Axilla of HER2+ Breast Cancer in the Z1071 Era: A Propensity-Score-Matched Analysis of the NCDB.

INTRODUCTION: We aim to analyze survival outcomes for sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND) in human epidermal growth factor receptor (HER2)+ infiltrative ductal carcinoma (IDC) that demonstrate complete clinical response (cCR) to neoadjuvant systemic therapy (NAST) after initial presentation with clinical N1 (cN1) disease. METHODS: NCDB 2004-2017 was utilized for the analysis. Female patients with unilateral HER2+ IDC, stage cT1-T4 cN1, who demonstrated cCR to NAST with reported definitive axillary surgical management were included. Patients were propensity score matched, and overall survival (OS) was compared. Cox regression analysis was used to identify survival predictors. RESULTS: 6453 patients were selected, of whom 2461 (38.1%) had SLNB and 3992 (69.1%) had ALND as definitive axillary surgical management. The trend of SLNB utilization increased from 20% in 2012 to 50% in 2017. A total of 2454 patients were matched from each group with adequate adjustment for all variables. There was no difference in OS between SLNB versus ALND (84.03 ± 0.36 versus 84.62 ± 0.42 months; p = 0.522). Cox regression identified age, cT stage, primary tumor response to NAST, ypN+, and endocrine therapy as significant OS predictors. In subgroup analysis of patients with ypN+ who had SLNB as a definitive procedure, primary tumor response to NAST and continuation of adjuvant chemotherapy were associated with improved OS. CONCLUSION: In cN1 HER2+ IDC patients who demonstrate cCR to NAST, SLNB is a reasonable definitive procedure for axillary management with comparable OS outcomes to ALND. However, higher-level data are required to determine the appropriate management in the case of ypN+.

Adenomyoepithelioma of the breast: Case series and literature review.

Adenomyoepithelioma of the breast is a rare tumor consisting of both epithelial and myoepithelial cells. Malignant transformation of either cell line can occur. We describe the imaging features, clinical presentation, and management of seven cases of biopsy-proven adenomyoepithelioma at our institution.

Feasibility of Axillary Lymph Node Localization and Excision Using Radar Reflector Localization.

INTRODUCTION: Neoadjuvant chemotherapy (NAC) is commonly used for patients with clinically detected nodal metastases. Sentinel lymph node biopsy (SLNB) after NAC is feasible. Excision of biopsy-proven positive lymph nodes in addition to SLNB, termed targeted axillary dissection (TAD), decreases the false-negative rate of SLNB alone. Positive nodes can be marked with radar reflector-localization (RRL) clips. We report our institutional experience with RRL-guided TAD and demonstrate its safety and feasibility. PATIENTS AND METHODS: We performed an institutional review board-approved retrospective review of consecutive clinically node-positive female patients with breast cancer treated with NAC and RRL-guided TAD between January 2017 and September 2019. Clinicopathologic and treatment data were collected; descriptive statistics are reported. RESULTS: Forty-five patients were analyzed; the median age was 55 years (range, 20-72 years), and the median body mass index was 27.2 kg/m2 (range, 16.5-40.4 kg/m2). All patients received NAC, primary breast surgery, and TAD. All clinically detected nodal metastases were confirmed with percutaneous biopsy and marked with a biopsy clip. RRL clips were implanted a median of 8 days (range, 1-167 days) prior to surgery; all were retrieved without complications. The RRL node was identified as the sentinel lymph node in 36 (80%) patients. Twenty-five patients had positive nodes, of which 24 were identified by RRL node excision, and 1 (4%) patient had a positive node identified by SLNB but not RRL. Over a median follow-up time of 29.6 months, 5 patients recurred (1 local, 4 distant). CONCLUSIONS: RRL-guided TAD after NAC is safe and feasible. This technique allows for adequate assessment of the nodal basin and helps confirm excision of the previously biopsied positive axillary node.

A Phase I Trial of Talimogene Laherparepvec in Combination with Neoadjuvant Chemotherapy for the Treatment of Nonmetastatic Triple-Negative Breast Cancer.

PURPOSE: Talimogene laherparepvec (TVEC) is an oncolytic herpes simplex 1 virus approved for treatment of melanoma. We hypothesized intratumoral TVEC may enhance response to neoadjuvant chemotherapy (NAC). This article reports the results of a trial combining NAC with TVEC for triple-negative breast cancer (TNBC). PATIENTS AND METHODS: Patients with stage II-III TNBC enrolled in a 3+3 phase I trial (NCT02779855) of two TVEC dose levels [DL; DL 1 = 106 plaque-forming units (PFU) × 5 doses; DL 2 = 106 PFUs first dose, then 108 PFUs × 4 doses] on weeks 1, 4, 6, 8, and 10 plus weekly paclitaxel (80 mg/m2) for 12 weeks, followed by doxorubicin/cyclophosphamide (60/600 mg/m2) every 2 weeks for 8 weeks. Postoperative response assessment using residual cancer burden (RCB) was performed. Primary endpoints were safety and MTD. Secondary endpoints were RCB0 rate and immune correlates. Dose-limiting toxicity (DLT) rule was grade 3-5 adverse events due to TVEC during first 5 weeks. RESULTS: Nine patients [DL 1 (n = 3); DL 2 (n = 6)] were enrolled. Six had stage II disease, and 3 had stage III (6 clinically N+). No DLTs occurred, and MTD was DL 2. Most common toxicities with TVEC were fever (n = 8), chills (n = 3), hematomas (n = 3), and injection site pain (n = 3). Thromboembolic events (n = 2) and bradycardia (n = 1) occurred during or after NAC. Five patients (55%) achieved RCB0, 2 had RCB1 (22%), and 2 had RCB2 (22%). CONCLUSIONS: The addition of TVEC to NAC was feasible at the approved dose, with manageable toxicity. The complete response rate was 55%.

Comparison of three anti-coccidioides antibody enzyme immunoassay kits for the diagnosis of coccidioidomycosis.

Coccidioidomycosis is a common cause of community-acquired pneumonia in endemic areas of the southwestern United States. Clinical presentations range from self-limited disease to severe, disseminated disease. As such, early and accurate diagnosis is essential to ensure appropriate treatment and monitoring. Currently available diagnostic testing has variable accuracy, particularly in certain patient populations, and new tests may offer improved accuracy for the diagnosis of coccidioidomycosis. Serum samples from patients with coccidioidomycosis and controls were tested for immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies using the MVista Coccidioides antibody detection EIA and two commonly used commercial enzyme immunoassay (EIA) kits: the IMMY Omega EIA and the Meridian Premier EIA. The sensitivity of the IgG antibody detection was 87.4% using the MVista test compared to 46.6% for IMMY and 70.9% for Meridian. The sensitivity for IgM antibody detection was 61.2% for the MVista test, 22.3% for IMMY and 29.1% for Meridian. For IgG antibody detection, specificity was 90% for the MVista EIA, 94.6% for IMMY, 96.4% for Meridian. For IgM antibody detection, specificity was 95.3% for the MVista test 98.2% for IMMY and 99.1% for Meridian. The MVista Coccidioides antibody EIA offers improved sensitivity, including among high-risk patient populations, for the detection of IgG and IgM antibodies in comparison to other currently available EIAs.

Strategies to Combat Human Epidermal Growth Factor Receptor 2 (HER2) Resistance in HER2-Positive Breast Cancer.

The discovery of human epidermal growth factor receptor 2 (HER2) and its role in breast cancer led to the development of the first targeted antibody treatment for HER2-positive breast cancer. This treatment breakthrough led to remarkable improvements in both early and late survival. Unfortunately, not all patients with HER2 breast cancer responded positively; some have innate resistance to treatment and others develop resistance over time. In this review, we discuss some research that is currently underway to understand HER2 resistance and strategies in overcoming it.

Implant-sparing Mastectomy: An Alternative for Women Undergoing Mastectomy With Retropectoral Implants.

INTRODUCTION: Implant-sparing mastectomy (ISM) is a skin-sparing mastectomy that preserves a retropectoral implant and potentially eliminates the need for tissue expansion or complex reconstruction. This study aimed to determine oncologic and surgical outcomes and reconstructive patterns in patients undergoing ISM. PATIENTS AND METHODS: A single-institution, retrospective review of patients undergoing ISM from 2006 to 2018 was performed. Patient/tumor characteristics, stage, adjuvant therapy use, 90-day complication rates, reconstruction type, and disease recurrence were collected. RESULTS: A total of 121 ISMs in 73 women were performed. Seventy (57.9%) ISMs were for breast cancer (BC) treatment and 51 (42.1%) for prophylaxis. Among BC cases, 72.3% were cT1/cT2 and 73.8% were cN0; 72.3% received systemic therapy and 33.8% received radiation therapy. There were 3 deaths owing to BC at the median follow-up of 35 months. Among 5 recurrences, only 1 was local. There was no BC identified after prophylactic ISM. Total 90-day complication rate per ISM was 15.7%. Rates were 0.8% for both seroma and wound infection, 2.5% for wound dehiscence, 3.3% for hematoma, and 8.2% for skin necrosis. The majority (72.6%) of patients required only implant exchange for reconstruction. Overall use of autologous reconstruction was low (12.3%); 77.8% of flaps were performed in patients receiving radiation therapy. CONCLUSION: ISM is a unique approach for patients pursuing mastectomy for BC treatment or prevention with equivalent oncologic outcomes and complication rates to mastectomy with reconstruction. Reconstruction for the majority was markedly simplified by elimination of tissue expansion while maintaining a low rate of flap reconstruction.