Outcomes in Nonmetastatic Hormone Receptor-Positive HER2-Negative Pure Mucinous Breast Cancer: A Multicenter Cohort Study.

BACKGROUND: Although considered a favorable subtype, pure mucinous breast cancer (PMBC) can recur, and evidence for adjuvant therapy is limited. We aimed to compare outcomes of nonmetastatic PMBC with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) to address these uncertainties. METHODS: Individual patient-level data from 6 centers on stage I-III hormone receptor-positive and HER2-negative PMBC, IDC, and ILC were used to analyze recurrence-free interval (RFI), recurrence-free survival (RFS), and overall survival (OS), and to identify prognostic factors for PMBC. RESULTS: Data from 20,684 IDC cases, 1,475 ILC cases, and 943 PMBC cases were used. Median follow-up was 6.6 years. Five-year RFI, RFS, and OS for PMBC were 96.1%, 94.9%, and 98.1%, respectively. On multivariable Cox regression, PMBC demonstrated superior RFI (hazard ratio [HR], 0.59; 95% CI, 0.43-0.80), RFS (HR, 0.70; 95% CI, 0.56-0.89), and OS (HR, 0.71; 95% CI, 0.53-0.96) compared with IDC. ILC showed comparable outcomes to IDC. Fewer than half (48.7%) of recurrences in PMBC were distant, which was a lower rate than for IDC (67.3%) and ILC (80.6%). In contrast to RFI, RFS events were driven more by non-breast cancer deaths in older patients. Significant prognostic factors for RFI among PMBC included positive lymph node(s) (HR, 2.42; 95% CI, 1.08-5.40), radiotherapy (HR, 0.44; 95% CI, 0.23-0.85), and endocrine therapy (HR, 0.25; 95% CI, 0.09-0.70). No differential chemotherapy associations with outcomes were detected across PMBC subgroups by nodal stage, tumor size, and age. A separate SEER database analysis also did not find any association of improved survival with adjuvant chemotherapy in these subgroups. CONCLUSIONS: Compared with IDC, PMBC demonstrated superior RFI, RFS, and OS. Lymph node negativity, adjuvant radiotherapy, and endocrine therapy were associated with superior RFI. Adjuvant chemotherapy was not associated with better outcomes.

Social support during re-entry period and long-term quality of life in breast cancer survivors: a 10-year longitudinal cohort study.

PURPOSE: This study evaluated the association between social support during the re-entry period and long-term health-related quality of life (HRQoL) in breast cancer survivors using a longitudinal cohort study. METHODS: This is a prospective cohort study with 275 breast cancer survivors who reported HRQoL at 5 and 10 years after diagnosis. Social support for the re-entry period was measured 3 years after diagnosis using the Medical Outcome Study Social Support Survey (MOS-SSS). HRQoL was evaluated using the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) and Breast Cancer-Specific Module (BR-23). Multivariable linear regression analysis was performed to evaluate HRQoL at 5 and 10 years after diagnosis by level of social support during the re-entry period. RESULTS: The mean (SD) of social support during re-entry period was 68.5. The low social support (LSS, score < 55) group during the re-entry period had a significantly lower HRQoL (mean difference = - 12.93) compared to moderate or high social support (MHSS, score ≥ 55) group. 5 and 10 years after diagnosis, the LSS group continued to demonstrate lower HRQoL (5 years: - 7.17; 10 years: - 7.85) compared to the MHSS group. The LSS group were more likely to have lower role and social function scores, and higher fatigue, pain, and financial problems compared to the MHSS group at 10 years after diagnosis. CONCLUSIONS: Breast cancer survivors who received lower social support during the re-entry period were more likely to experience poorer HRQoL in the long term than those who did not.

Impact of residual microcalcifcations on prognosis after neoadjuvant chemotherapy in breast cancer patients.

BACKGROUND: Residual microcalcifications after neoadjuvant chemotherapy (NAC) are challenging for deciding extent of surgery and questionable for impact on prognosis. We investigated changes in the extent and patterns of microcalcifications before and after NAC and correlated them with pathologic response. We also compared prognosis of patients depending on presence of residual microcalcifications after NAC. METHODS: A total of 323 patients with invasive breast carcinoma treated with neoadjuvant chemotherapy at Kangbuk Samsung Hospital and Samsung Medical center from March 2015 to September 2018 were included. Patients were divided into four groups according to pathologic response and residual microcalcifications. Non-pCRw/mic group was defined as breast non-pCR with residual microcalcifications. Non-pCRw/o mic group was breast non-pCR without residual microcalcifications. pCRw/mic group was breast pCR with residual microcalcifications. pCRw/o mic group was breast pCR without residual microcalcifications. The first aim of this study is to investigate changes in the extent and patterns of microcalcifications before and after NAC and to correlate them with pathologic response. The second aim is to evaluate oncologic outcomes of residual microcalcifications according to pathologic response after NAC. RESULTS: There were no statistical differences in the extent, morphology, and distribution of microcalcifications according to pathologic response and subtype after NAC (all p > 0.05). With a median follow-up time of 71 months, compared to pCRw/o mic group, the hazard ratios (95% confidence intervals) for regional recurrence were 5.190 (1.160-23.190) in non-pCRw/mic group and 5.970 (1.840-19.380) in non-pCRw/o mic group. Compared to pCRw/o mic group, the hazard ratios (95% CI) for distant metastasis were 8.520 (2.130-34.090) in non-pCRw/mic group, 9.120 (2.850-29.200) in non-pCRw/o mic group. Compared to pCRw/o mic, the hazard ratio (95% CI) for distant metastasis in pCRw/mic group was 2.240 (0.230-21.500) without statistical significance (p = 0.486). CONCLUSIONS: Regardless of residual microcalcifications, patients who achieved pCR showed favorable long term outcome compared to non-pCR group.

Migratory Tumor Cells Cooperate with Cancer Associated Fibroblasts in Hormone Receptor-Positive and HER2-Negative Breast Cancer.

Hormone receptor-positive and HER2-negative breast cancer (HR+/HER2-BC) is the most common type with a favorable prognosis under endocrine therapy. However, it still demonstrates unpredictable progression and recurrences influenced by high tumoral diversity and microenvironmental status. To address these heterogeneous molecular characteristics of HR+/HER2-BC, we aimed to simultaneously characterize its transcriptomic landscape and genetic architecture at the same resolution. Using advanced single-cell RNA and DNA sequencing techniques together, we defined four distinct tumor subtypes. Notably, the migratory tumor subtype was closely linked to genomic alterations of EGFR, related to the tumor-promoting behavior of IL6-positive inflammatory tumor-associated fibroblast, and contributing to poor prognosis. Our study comprehensively utilizes integrated analysis to uncover the complex dynamics of this breast cancer subtype, highlighting the pivotal role of the migratory tumor subtype in influencing surrounding cells. This sheds light on potential therapeutic targets by offering enhanced insights for HR+/HER2-BC treatment.

YAP, CTGF and Cyr61 are overexpressed in tamoxifen-resistant breast cancer and induce transcriptional repression of ERα.

About 70% of breast cancers overexpress estrogen receptor α (ERα, encoded by ESR1). Tamoxifen, a competitive inhibitor of estrogen that binds to ER, has been widely used as a treatment for ER-positive breast cancer. However, 20-30% of breast cancer is resistant to tamoxifen treatment. The mechanisms underlying tamoxifen resistance remain elusive. We found that Yes-associated protein (YAP; also known as YAP1), connective tissue growth factor (CTGF; also known as CCN2) and cysteine-rich angiogenic inducer 61 (Cyr61; also known as CCN1) are overexpressed, while ERα is downregulated in tamoxifen-resistant breast cancer. Inhibition of YAP, CTGF and Cyr61 restored ERα expression and increased sensitivity to tamoxifen. Overexpression of YAP, CTGF, and Cyr61 led to downregulation of ERα and conferred resistance to tamoxifen in ER-positive breast cancer cells. Mechanistically, CTGF and Cyr61 downregulated ERα expression at the transcriptional level by directly binding to the regulatory regions of the ERα-encoding gene, leading to increased tamoxifen resistance. Also, CTGF induced Glut3 (also known as SLC2A3) expression, leading to increased glycolysis, which enhanced cell proliferation and migration in tamoxifen-resistant cells. Together, these results demonstrate a novel role of YAP, CTGF and Cyr61 in tamoxifen resistance and provide a molecular basis for their function in tamoxifen-resistant breast cancer.

Association of Fat Graft with Breast Cancer Recurrence in Implant-Based Reconstruction: Does the Timing Matter?

PURPOSE: In two-stage prosthetic breast reconstruction, autologous fat graft (AFG) is often conducted simultaneously with the second-stage operation, which is usually performed shortly after mastectomy. There is a paucity of studies evaluating whether conducting AFG early, with a relatively short interval from the primary operation, is oncologically safe. This study aimed to evaluate potential associations of AFG with breast cancer prognosis, focusing on its timing. METHODS: Patients with invasive breast cancer who underwent immediate two-stage prosthetic reconstruction following mastectomy between 2011 and 2016 were identified. They were categorized into two groups by whether AFG was performed during the second-stage operation. Cumulative incidence of oncologic events was compared between the two groups, after stratifying patients by the time interval between mastectomy and the second-stage operation (≤ 12 months vs. > 12 months). RESULTS: Of 267 cases that met the selection criteria, 203 underwent the second-stage operation within 12 months of mastectomy. AFG was performed for 112 cases and was not performed in 91 cases. The two groups showed similar baseline characteristics including tumor stage and adjuvant treatments. Compared with the control, AFG was associated with lower locoregional recurrence-free survival and disease-free survival, and this difference remained significant after adjusting for other variables including tumor stage. In the 64 cases undergoing the operation after 12 months following mastectomy, oncologic outcomes did not differ between the two groups. CONCLUSION: Our results suggest that AFG timing in relation to mastectomy may be associated with risks for breast cancer recurrence.

Tumorigenicity of EGFR- and/or HER2-Positive Breast Cancers Is Mediated by Recruitment of Tumor-Associated Macrophages.

Basal-like breast cancer (BLBC) has a clinically aggressive nature. It is prevalent in young women and is known to often relapse rapidly. To date, the molecular mechanisms regarding the aggressiveness of BLBC have not been fully understood. In the present study, mechanisms of aggressiveness of BLBC involving EGFR and/or HER2 expression and interactions between tumor and tumor-associated macrophages (TAMs) were explored. The prognosis of breast cancer patients who underwent surgery at Samsung Medical Center was analyzed. It was found that the co-expression of EGFR and HER2 was associated with a worse prognosis. Therefore, we generated EGFR-positive BLBC cells with stable HER2 overexpression and analyzed the profile of secretory cytokines. Chemokine (C-C motif) ligand 2 (CCL2) expression was increased in HER2-overexpressed BLBC cells. Recombinant human CCL2 treatment augmented the motility of TAMs. In addition, the conditioned culture media of HER2-overexpressed BLBC cells increased the motility of TAMs. Furthermore, activation of TAMs by CCL2 or the conditioned culture media of HER2-overexpressed cells resulted in the production of pro-inflammatory cytokines, such as IL-8 and IL-1ß. These observations reveal that CCL2 derived from EGFR and HER2 co-expressed BLBC cells can lead to increased TAM recruitment and the induction of IL-8 and IL-1ß from recruited TAMs, triggering the tumorigenesis of breast cancer with the expression of both EGFR and HER2. Our findings demonstrate that EGFR+ and HER2+ BLBC aggressiveness is partially mediated through the interaction between BLBC and TAMs recruited by CCL2.

A Retrospective Exploratory Analysis for Serum Extracellular Vesicles Reveals APRIL (TNFSF13), CXCL13, and VEGF-A as Prognostic Biomarkers for Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer.

Neoadjuvant chemotherapy (NAC) is widely used as a standard treatment for early-stage triple-negative breast cancer (TNBC). While patients who achieve pathologic complete response (pCR) have a highly favorable outcome, patients who do not achieve pCR have variable prognoses. It is important to identify patients who are most likely to have poor survival outcomes to identify candidates for more aggressive therapeutic approaches after NAC. Many studies have demonstrated that cytokines and growth factors packaged into extracellular vesicles (EVs) have an essential role in tumor progression and drug resistance. In this study, we examined the role of serum-derived EV-associated cytokines as prognostic biomarkers for long-term outcomes in patients who underwent anthracycline-taxane-based NAC. We isolated extracellular vesicles from the serum of 190 TNBC patients who underwent NAC between 2015 and 2018 at Samsung Medical Center. EV-associated cytokine concentrations were measured with ProcartaPlex Immune Monitoring 65-plex panels. The prognostic value of EV-associated cytokines was studied. We found that patients with high EV_APRIL, EV_CXCL13, and EV_VEGF-A levels had shorter overall survival (OS). We further evaluated the role of these selected biomarkers as prognostic factors in patients with residual disease (RD) after NAC. Even in patients with RD, high levels of EV_APRIL, EV_CXCL13, and EV_VEGF-A were correlated with poor OS. In all subgroup analyses, EV_CXCL13 overexpression was significantly associated with poor overall survival. Moreover, multivariate analysis indicated that a high level of EV_CXCL13 was an independent predictor of poor OS. Correlation analysis between biomarker levels in EVs and serum showed that EV_VEGF-A positively correlated with soluble VEGF-A but not CXCL13. An elevated level of soluble VEGF-A was also associated with poor OS. These findings suggest that EV_APRIL, EV_CXCL13, and EV_VEGF-A may be useful in identifying TNBC patients at risk of poor survival outcomes after NAC.

Surgical margin status and survival outcomes of breast cancer patients treated with breast-conserving surgery and whole-breast irradiation after neoadjuvant chemotherapy.

PURPOSE: The definition of "no tumor on ink" is generally applied for clear resection margin (RM) after breast-conserving surgery (BCS). However, few studies reported the effect of RM in the setting of neoadjuvant chemotherapy (NAC). We investigated the association between RM status and survival outcomes for those who underwent BCS after NAC for breast cancer. METHODS: We retrospectively reviewed the data of 2,803 patients who underwent BCS and whole-breast irradiation after NAC between January 2008 and December 2016 from three institutions in South Korea. RESULTS: The 786 patients in the pathologic complete response group (RpCR) had significantly longer local recurrence-free survival (LRFS) than the 1,949 patients in clear or close RM and non-pCR group (R0) and the 68 patients in involved RM and non-pCR group (R1) (vs. R0, p = 0.001; vs. R1, p = 0.049). Patients in R0 showed no benefit in LRFS compared to R1 on both log-rank test (HR = 1.20; 95% C.I., 0.49-2.93; p = 0.692) and Cox regression analysis (HR = 2.05; 95% C.I., 0.64-6.58; p = 0.227). Subgroup analysis according to tumor subtypes revealed that there was no significant difference in LRFS, distant metastasis-free survival, and recurrence-free survival between the R0 and R1 group. Additionally, among 286 patients with pCR with residual ductal carcinoma in situ (DCIS) alone, RM status was not significantly associated with LRFS. CONCLUSION: Clear RM of specimen does not have benefit on LRFS after NAC. Additionally, for the patients showing pCR with residual DCIS in the breast, margin involvement also did not affect the risk of local recurrence.

Immediate breast reconstruction has no impact on the oncologic outcomes of patients treated with post-mastectomy radiation therapy: a comparative analysis based on propensity score matching.

PURPOSE: To investigate the impact of immediate breast reconstruction (iBR) on patients treated with post-mastectomy radiation therapy (PMRT) using propensity score matching (PSM). METHODS: After a retrospective review of patients treated with PMRT between 2008 and 2017, we included 153 patients who underwent iBR and 872 patients who did not undergo iBR. Among the 153 patients who underwent iBR, 34 received one-stage iBR with autologous tissue and 119 received two-stage iBR. Conventional fractionated PMRT with a total dose of 50-50.4 Gy in 25-28 fractions was performed in all patients. Propensity scores were calculated via logistic regression. RESULTS: Patients who underwent iBR were younger, had early stage disease, and had more frequent hormone receptor-positive tumor than those who did not undergo iBR. After PSM, 127 patients from each group with well-balanced characteristics were selected. With a median follow-up of 67.5 months, iBR led to better 6-year disease-free survival rates compared to no iBR before PSM (84.8% vs. 71.4%, p = 0.003); after PSM, there was no significant difference (84.8% vs. 75.5%, p = 0.130). On multivariable analysis in the matched cohort, iBR was not associated with inferior disease-free survival (hazard ratio, 0.67; p = 0.175). In the sensitivity analysis, iBR was not associated with a lower disease-free survival across all prognostic groups. The 5-year cumulative incidence of iBR failure was 15.0%. CONCLUSION: In patients with adverse pathologic factors planning to receive PMRT, iBR did not compromise oncologic outcomes. In addition, iBR can be considered in patients treated with PMRT with several clinicopathologic risk factors.

Surgical and Oncologic Outcomes of Robotic and Conventional Nipple-Sparing Mastectomy with Immediate Reconstruction: International Multicenter Pooled Data Analysis.

BACKGROUND: Robotic nipple-sparing mastectomy (RNSM) has been developed to reduce conspicuous scar and increase the quality of life in women. This study aimed to evaluate the surgical and oncologic outcomes of RNSM with immediate breast reconstruction (IBR) compared with conventional nipple-sparing mastectomy (CNSM). PATIENTS AND METHODS: This international multicenter, pooled analysis of individual patient-level data enrolled a total of 755 procedures in 659 women (609 had breast cancer and 50 underwent risk-reducing mastectomy) who underwent nipple-sparing mastectomy with IBR. Surgical and oncologic outcomes, including 30-days postoperative (POD 30d) complication rate, nipple necrosis rate, grade of Clavien-Dindo classification, disease-free survival, and overall survival, were evaluated. Propensity score-matched analyses were performed to adjust for confounding factors. RESULTS: The median age of both the RNSM and CNSM groups was 45 years. The RNSM group had lower body mass index (BMI) and a higher proportion of benign disease compared with the CNSM group. POD 30d complications and postoperative complication grade III rates were lower in the RNSM group than in the CNSM group (p < 0.05). The nipple necrosis rate was 2.2% and 7.8% for RNSM and CNSM, respectively (p = 0.002). After propensity score matching, significantly lower rates of POD 30d complications, nipple necrosis, and postoperative complication grade III occurred in the RNSM group than in the CNSM group (all p < 0.05). Oncologic outcomes were not significantly different between the two groups. CONCLUSION: RNSM can provide better cosmetic results with favorable surgical and oncologic outcomes for women with early breast cancer or BRCA mutation.

Factors Affecting Pathologic Complete Remission in Patients with Hormone Receptor-Positive and Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer Receiving Neoadjuvant Chemotherapy.

INTRODUCTION: Pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) is associated with improvement in survival outcomes. This study evaluated the pCR in patients with hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer after NAC. METHODS: We evaluated 417 patients who were diagnosed with invasive breast cancer and treated with NAC followed by curative surgery between January 2007 and December 2020 and analyzed the pCR for HR-positive and HER2-negative breast cancer. RESULTS: The median age at the time of surgery was 45.4 years, and 9.1% of patients (38 of 417) with HR-positive/HER2-negative status had pCR. Among patients with HR-positive/HER2-negative breast cancer, patients with single HR-positivity had a 20.2% pCR rate, and patients with double HR-positivity had a 4.4% pCR rate. Patients with a high Ki-67 index exhibited a higher pCR rate than those with a lower Ki-67 index (14.5% vs. 3.2%). Patients with single HR-positive and high Ki-67 values exhibited a significantly higher pCR rate than those with double HR-positive and low Ki-67 values (27.8% vs. 2.1%; p < 0.001). CONCLUSION: NAC could improve prognosis in patients with HR-positive/HER2-negative breast cancer with a single HR-positive and high Ki-67 values.

Effect of mind and body education on quality of life among young breast cancer patients: a randomized controlled trial.

PURPOSE: This study aim was to evaluate efficacy of the combination with cosmetic and psychosocial education program on body image, sexual function, and emotional function among young-onset breast cancer (YBC). METHODS: An unblended, randomized, controlled trial design was conducted in patients newly diagnosed with stage I-III breast cancer from 2014 to 2015. The intervention group received a structured education program including appearance management and mind control for 4 weeks. The outcome of this study shows effect on body image and sexual functioning and a distress due to altered appearance and anxiety after the intervention and 6 months after intervention. RESULTS: Among 228 eligible patients, 109 (47.8%) agreed to participate in the present study and were randomized to intervention (n = 54) or control (n = 55) groups. After intervention, the intervention group reported significantly better body image compared to the control group (mean score of 75.0 vs. 59.3, respectively; P < 0.01). The intervention group also reported significantly lower levels of distress due to altered appearance and higher levels of sexual functioning compared to the control group after the intervention. The effects were maintained even 6 months after intervention. CONCLUSION(S): Body image intervention for YBC had effect on improving body image and sexual functioning and a reduction in distress due to altered appearance and anxiety. Trial registration number and date of registration: The study was registered at the Clinical Research Information Service (no. KCT0001191, https://cris.nih.go.kr/cris ) on 23 July 2014.

Divorce after breast cancer diagnosis and its impact on quality of life.

OBJECTIVE: This study aims to identify factors associated with divorce following breast cancer diagnosis and measures the impact of divorce on the quality of life (QoL) of patients. METHODS: We used cross-sectional survey data collected at breast cancer outpatient clinics in South Korea from November 2018 to April 2019. Adult breast cancer survivors who completed active treatment without any cancer recurrence at the time of the survey (N = 4,366) were included. The participants were classified into two groups: "maintaining marriage" and "being divorced," between at the survey and at the cancer diagnosis. We performed logistic regression and linear regression to identify the factors associated with divorce after cancer diagnosis and to compare the QoL of divorced and nondivorced survivors. RESULTS: Approximately 11.1/1,000 of married breast cancer survivors experienced divorce after cancer diagnosis. Younger age, lower education, and being employed at diagnosis were associated with divorce. Being divorced survivors had significantly lower QoL (Coefficient [Coef] = -7.50; 95% CI = -13.63, -1.36), social functioning (Coef = -9.47; 95% CI = -16.36, -2.57), and body image (Coef = -8.34; 95% CI = -6.29, -0.39) than survivors who remained married. They also experienced more symptoms including pain, insomnia, financial difficulties, and distress due to hair loss. CONCLUSION: Identifying risk factors of divorce will ultimately help ascertain the resources necessary for early intervention.

SIDR: simultaneous isolation and parallel sequencing of genomic DNA and total RNA from single cells.

Simultaneous sequencing of the genome and transcriptome at the single-cell level is a powerful tool for characterizing genomic and transcriptomic variation and revealing correlative relationships. However, it remains technically challenging to analyze both the genome and transcriptome in the same cell. Here, we report a novel method for simultaneous isolation of genomic DNA and total RNA (SIDR) from single cells, achieving high recovery rates with minimal cross-contamination, as is crucial for accurate description and integration of the single-cell genome and transcriptome. For reliable and efficient separation of genomic DNA and total RNA from single cells, the method uses hypotonic lysis to preserve nuclear lamina integrity and subsequently captures the cell lysate using antibody-conjugated magnetic microbeads. Evaluating the performance of this method using real-time PCR demonstrated that it efficiently recovered genomic DNA and total RNA. Thorough data quality assessments showed that DNA and RNA simultaneously fractionated by the SIDR method were suitable for genome and transcriptome sequencing analysis at the single-cell level. The integration of single-cell genome and transcriptome sequencing by SIDR (SIDR-seq) showed that genetic alterations, such as copy-number and single-nucleotide variations, were more accurately captured by single-cell SIDR-seq compared with conventional single-cell RNA-seq, although copy-number variations positively correlated with the corresponding gene expression levels. These results suggest that SIDR-seq is potentially a powerful tool to reveal genetic heterogeneity and phenotypic information inferred from gene expression patterns at the single-cell level.

Prevalence, treatment patterns, and prognosis of low estrogen receptor-positive (1% to 10%) breast cancer: a single institution's experience in Korea.

PURPOSE: To determine prevalence, clinicopathological characteristics, initial treatments, and outcomes associated with low estrogen receptor (ER)-expressing invasive breast cancer. METHODS: This retrospective, non-interventional database study included patients undergoing surgery with curative intent for invasive ductal or lobular breast cancer. Patients were treated between January 2003-December 2012. Demographics, clinicopathological characteristics, initial treatments, and outcomes were abstracted from patient records. Patients were categorized using immunohistochemistry to determine ER, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) levels. ER-positive patients were subclassified as ER-low (1% to 10%) and ER-high (> 10%) according to the Allred Proportion Score. Disease-free survival (DFS) and overall survival (OS) were estimated by the Kaplan-Meier method and compared among groups by log-rank test. RESULTS: 5930 patients were included (median follow-up, 80.9 months). Of all patients included, 117 (2.0%) had ER-low tumors: 63 (53.8%) of whom had HER2- tumors and 54 (46.2%) HER2+ tumors. Five-year DFS and OS were highest in the ER-high/HER2- cohort (94.0% and 98.6%, respectively) and lowest in the triple-negative breast cancer (TNBC; 81.3% and 90.1%) and ER-low/HER2- (85.7% and 92.1%) cohorts. Menopausal status, elevated Ki-67, higher nuclear grade, higher tumor stage, presence of lymphovascular invasion, greater regional lymph node involvement, and larger tumor size were all potential prognostic factors for shorter DFS and OS. CONCLUSION: Patients with ER-low/HER2- breast cancer had similar clinicopathological characteristics, treatments, and outcomes as patients with TNBC irrespective of disease setting. Further research is needed to understand predictive and prognostic factors associated with ER-low/HER2- disease.

Prediction of pathologic complete response to neoadjuvant chemotherapy using machine learning models in patients with breast cancer.

BACKGROUND: The aim of this study was to develop a machine learning (ML) based model to accurately predict pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) using pretreatment clinical and pathological characteristics of electronic medical record (EMR) data in breast cancer (BC). METHODS: The EMR data from patients diagnosed with early and locally advanced BC and who received NAC followed by curative surgery were reviewed. A total of 16 clinical and pathological characteristics was selected to develop ML model. We practiced six ML models using default settings for multivariate analysis with extracted variables. RESULTS: In total, 2065 patients were included in this analysis. Overall, 30.6% (n = 632) of patients achieved pCR. Among six ML models, the LightGBM had the highest area under the curve (AUC) for pCR prediction. After hyper-parameter tuning with Bayesian optimization, AUC was 0.810. Performance of pCR prediction models in different histology-based subtypes was compared. The AUC was highest in HR+HER2- subgroup and lowest in HR-/HER2- subgroup (HR+/HER2- 0.841, HR+/HER2+ 0.716, HR-/HER2 0.753, HR-/HER2- 0.653). CONCLUSIONS: A ML based pCR prediction model using pre-treatment clinical and pathological characteristics provided useful information to predict pCR during NAC. This prediction model would help to determine treatment strategy in patients with BC planned NAC.

Does chemotherapy or radiotherapy affect the postoperative complication in breast cancer patients who underwent immediate breast reconstruction with tissue expander?

BACKGROUND: Immediate breast reconstruction with tissue expander in breast cancer patients who were expected to receive adjuvant therapy, such as chemotherapy or radiotherapy, has been a topic of debate. Postoperative complications from tissue expander procedures can delay the timing of adjuvant treatment and subsequently increase the probability of recurrence. The purpose of this study was to identify the impact of chemotherapy and radiotherapy on postoperative complications in patients who underwent immediate reconstruction (IR) using tissue expander. METHODS: We conducted a retrospective study of 1081 breast cancer patients who underwent mastectomy and IR using tissue expander insertion between 2012 and 2017 in Samsung Medical Center. The patients were divided into two groups based on complications (complication group vs. no complication group). Complication group was regarded to have surgical removal or conservative treatment based on clinical findings such as infection, capsular contracture, seroma, hematoma, rupture, malposition, tissue viability, or cosmetic problem. The complication group had 59 patients (5.5%) and the no complication group had 1022 patients (94.5%). RESULTS: In univariate analysis, adjuvant radiotherapy and adjuvant chemotherapy were significantly associated with postoperative complications. In multivariate analysis, however, only higher pathologic N stage was significantly associated with postoperative complications (p < 0.001). Chemotherapy (p = 0.775) or radiotherapy (p = 0.825) were not risk factors for postoperative complications. CONCLUSIONS: IR with tissue expander after mastectomy may be a treatment option even when the patients are expected to receive adjuvant chemotherapy or radiotherapy. These results will aid patients who are concerned about the complications of IR caused by chemotherapy or radiotherapy determine whether or not to have IR. TRIAL REGISTRATION: Patients were selected and registered retrospectively, and medical records were evaluated.

Changes in Korean National Healthcare Insurance Policy and Breast Cancer Surgery Trend in Korea.

BACKGROUND: Since April 2015, the Korean National Health Insurance (NHI) has reimbursed breast cancer patients, approximately 50% of the cost of the breast reconstruction (BR) procedure. We aimed to investigate NHI reimbursement policy influence on the rate of immediate BR (IBR) following total mastectomy (TM). METHODS: We retrospectively analyzed breast cancer data between April 2011 and June 2016. We divided patients who underwent IBR following TM for primary breast cancer into "uninsured" and "insured" groups using their NHI statuses at the time of surgery. Univariate analyses determined the insurance influence on the decision to undergo IBR. RESULTS: Of 2,897 breast cancer patients, fewer uninsured patients (n = 625) underwent IBR compared with those insured (n = 325) (30.0% vs. 39.8%, P < 0.001). Uninsured patients were younger than those insured (median age [range], 43 [38-48] vs. 45 [40-50] years; P < 0.001). Pathologic breast cancer stage did not differ between the groups (P = 0.383). More insured patients underwent neoadjuvant chemotherapy (P = 0.011), adjuvant radiotherapy (P < 0.001), and IBR with tissue expander insertion (P = 0.005) compared with those uninsured. CONCLUSION: IBR rate in patients undergoing TM increased after NHI reimbursement.

The efficacy and safety of indocyanine green-hyaluronic acid mixture (LuminoMark™) for localization in patients with non-palpable breast lesions: a multi-center open-label parallel phase-2 clinical trial.

BACKGROUND: Increasing rates of breast cancer screening have been associated with an increasing frequency of non-palpable breast lesions detection. Preoperative breast lesion localization is essential for optimizing excision accuracy. This study aimed to evaluate the efficacy and safety of indocyanine green (ICG) hyaluronic acid injection as a novel mixture for localization. METHODS: We performed a prospective clinical trial with female patients who underwent surgery for non-palpable breast lesions. All patients were sequentially assigned to the control group (localization with activated charcoal), Test Group 1 (ICG-hyaluronic acid mixture 0.1 mL), or Test Group 2 (ICG-hyaluronic acid mixture 0.2 mL) by 1:1:1 ratio. RESULTS: A total of 44 patients were eligible for this study (Control Group = 14, Test Group 1 = 15, Test Group 2 = 15 patients). Fibroadenoma (n = 17, 38.6%) accounted for the largest proportion of diagnoses, and five patients (11.4%) were diagnosed with malignancies. There were no statistically significant differences in baseline characteristics among the three groups. The marking rate was over 86% in all groups, with no significant intergroup differences. Skin pigmentation was only observed in the control group. The mean accuracy of resection (the greatest diameter of the excised specimen divided by the greatest diameter of the preoperative lesion as observed using ultrasonography, with values closer to 1 reflecting a higher accuracy) was 3.7 in the control group, 2.2 in Test Group 1, and 2.1 in Test Group 2 (p = 0.037 between Controls and Test Group 1, p = 0.744 between Test Group 1 and Test Group 2, and p = 0.026 between Controls and Test Group 2). CONCLUSION: ICG-hyaluronic acid injection is a novel method that was shown to accurately localize non-palpable breast lesions and was associated with no skin pigmentation. Further research is required to apply this method to malignant breast lesions. Trial registration "A Multicenter Open-label, Parallel, Phase 2 Clinical Trial to Evaluate the Efficacy and Safety of LuminoMark™ Inj. (Conc. for Fluorescence) Localization in Patients with Non-palpable Breast Lesions" was prospectively registered as a trial (ClinicalTrials. gov Identifier: NCT03743259, date of registration: May 29, 2018, https://clinicaltrials.gov/ct2/show/NCT03743259 ).