Outcomes of sentinel node biopsy according to MRI response in an association with the subtypes in cN1-3 breast cancer after neoadjuvant systemic therapy, multicenter cohort study.

BACKGROUND: This study investigated the feasibility of sentinel lymph node biopsy (SLNB) after neoadjuvant systemic therapy (NAST) in patients with initially high nodal burden. METHODS: In the multicenter retrospective cohort, 388 individuals with cN1-3 breast cancer who underwent NAST and had SLNB followed by completion axillary lymph node dissection were included. In an external validation cohort, 267 patients with HER2+ or triple-negative breast cancer (TNBC) meeting similar inclusion criteria were included. Primary outcome was the false-negative rates (FNRs) of SLNB according to the MRI response and subtypes. We defined complete MRI responders as patients who experienced disappearance of suspicious features in the breast and axilla after NAST. RESULTS: In the multicenter retrospective cohort, 130 (33.5%) of 388 patients were of cN2-3, and 55 (14.2%) of 388 patients showed complete MRI responses. In hormone receptor-positive HER2- (n = 207), complete and non-complete responders had a high FNRs (31.3% [95% CI 8.6-54.0] and 20.9% [95% CI 14.1-27.6], respectively). However, in HER2+ or TNBC (n = 181), the FNR of complete MRI responders was 0% (95% CI 0-0), whereas that of non-complete responders was 33.3% (95% CI 20.8-45.9). When we validated our findings in the external cohort with HER2+ or TNBC (n = 267), of which 34.2% were cN2-3, the FNRs of complete were 7.1% (95% CI 0-16.7). CONCLUSIONS: Our findings suggest that SLNB can be a reliable option for nodal status evaluation in selected patients who have responded well to NAST, especially in HER2+ and TNBC patients who show a complete MRI response.

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.

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.

Mastectomy with Reconstruction Including Robotic Endoscopic Surgery (MARRES): a prospective cohort study of the Korea Robot-Endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG) and Korean Breast Cancer Study Group (KBCSG).

BACKGROUND: Robotic nipple-sparing mastectomy (RNSM) has emerged as a new treatment option for breast cancer and risk-reducing mastectomy (RRM) for women who have a high risk of pathogenic variants. Even though several studies have reported that RNSM is a feasible procedure, some argue that it should only be performed by specialized surgeons, and data on oncologic outcomes and patient-reported outcomes (PROs) are limited. Recently, the United States Food and Drug Administration and several surgeons warned that robotic breast surgery should be performed only by specialized surgeons and recommended that the benefits, risks, and alternatives of all available treatment options be discussed with patients so they can make informed treatment decisions. The Korea Robot-Endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG) has been established to evaluate, standardize, and teach this state-of-the-art procedure. We have designed a multicenter prospective cohort study entitled Mastectomy with Reconstruction Including Robot Endoscopic Surgery (MARRES) to report surgical, PRO, and oncologic outcomes. METHODS: MARRES is a multi-institution cohort study prospectively collecting data from patients undergoing mastectomy and reconstruction. The patient inclusion criteria are adult women older than 19 with breast cancer or a high risk of breast cancer (patients with BRCA1/2, TP53, PALB2 mutations, etc.), who have scheduled therapeutic or RRM and want immediate reconstruction. Surgical outcomes, including pre- and postoperative photos, oncologic outcomes, cost-effectiveness, and PRO, are collected. The primary endpoints are postoperative complication rates within 30 postoperative days and the Clavien-Dindo grade of postoperative complications within 180 postoperative days. The secondary endpoints are 5-year postoperative recurrence-free survival and cancer incidence rate (for those who underwent RRM), patient satisfaction with reconstruction expectations preoperative (baseline) and results within 6 to 12 postoperative months, surgeon satisfaction with postoperative results in 6 postoperative months, and cost-effectiveness of the definitive surgery. Patient recruitment will be completed in April 2025, and the target number of enrolled patients is 2000. DISCUSSION: This study will provide evidence about the surgical outcomes, oncologic outcomes, and patient satisfaction with RNSM and endoscopic nipple-sparing mastectomy (NSM), compared with conventional NSM. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT04585074. Registered April 8, 2020.

Robot-assisted Nipple-sparing Mastectomy With Immediate Breast Reconstruction: An initial Experience of the Korea Robot-endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG).

OBJECTIVE: The aim of this study was to present the results of early experience of robot-assisted nipple sparing mastectomy (RANSM). BACKGROUND: RANSM improves cosmetic outcomes over conventional nipple-sparing mastectomy. However, data on the feasibility and safety of the RANSM are limited. METHODS: Patients who underwent RANSM with immediate breast reconstruction as part of the Korea Robot-endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG) from November 2016 to January 2020 were enrolled. clinicopathologic characteristics, perioperative complications, and operation time were collected. RESULTS: Overall, 73 women underwent 82 RANSM procedures conducted by 11 breast surgeons at 8 institutions. The median patient age was 45.5 years old (20-66 years), and 52 (63.4%) patients were premenopausal. Invasive breast cancer was noted in 55 cases (40 cases were stage i, 11 cases were stage ii, and 4 cases were stage iii, respectively) and ductal carcinoma in-situ was recorded in 20 cases. Of those, 3 patients with BRCA1/2 mutation carriers underwent contralateral risk-reducing RANSM. The median length of hospitalization was 12.0 days (5.0-24.0 days). The incision location was the mid-axillary line and the median incision length was 50.0 mm (30.0-60.0 mm). Median total operation time, median total mastectomy time, and median reconstruction time was 307.0 minutes (163.0-796.0 minutes), 189.5 minutes (97.5-325.0 minutes), and 119.5 minutes (45.0-689.0 minutes). Only 2 cases (2.5%) required reoperation. Nipple ischemia was found in 9 cases (10.9%) but only 1 case (1.2%) required nipple excision given that 8 cases (9.7%) resolved spontaneously. Skin ischemia was observed in 5 cases (6.1%) and only 2 (2.4%) cases needed skin excision whereas 3 cases (3.6%) resolved spontaneously. There was no conversion to open surgery orcases of mortality. The mean time for mastectomy among surgeons who performed more than 10 cases was 182.3 minutes (± 53.7, minutes) and 195.4 minutes (± 50.4, minutes). CONCLUSION: This was the first report of RANSM conducted in the KoREa-BSG. RANSM is technically feasible and acceptable with a short learning curve. Further prospective research to evaluate surgical and oncologic outcomes is needed.

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.

No axillary surgical treatment for lymph node-negative patients after ultra-sonography [NAUTILUS]: protocol of a prospective randomized clinical trial.

BACKGROUND: Following sentinel lymph node biopsy (SLNB), the axillary recurrence rate is very low although SLNB has a false-negative rate of 5-10%. In the ACOSOG Z0011 trial, non-sentinel positive-lymph nodes were found in more than 20% of the axillary dissection group; the SLNB only group did not have a higher axillary recurrence rate. These findings raised questions about the direct therapeutic effect of the SLNB. SLNB has post-surgical complications including lymphedema. Considering advances in imaging modalities and adjuvant therapies, the role of SLNB in early breast cancer needs to be re-evaluated. METHODS: The NAUTILUS trial is a prospective multicenter randomized controlled trial involving clinical stage T1-2 and N0 breast cancer patients receiving breast-conserving surgery. Axillary ultrasound is mandatory before surgery with predefined imaging criteria for inclusion. Ultrasound-guided core needle biopsy or needle aspiration of a suspicious node is allowed. Patients will be randomized (1:1) into the no-SLNB (test) and SLNB (control) groups. A total of 1734 patients are needed, considering a 5% non-inferiority margin, 5% significance level, 80% statistical power, and 10% dropout rate. All patients in the two groups will receive ipsilateral whole-breast radiation according to a predefined protocol. The primary endpoint of this trial is the 5-year invasive disease-free survival. The secondary endpoints are overall survival, distant metastasis-free survival, axillary recurrence rate, and quality of life of the patients. DISCUSSION: This trial will provide important evidence on the oncological safety of the omission of SLNB for early breast cancer patients undergoing breast-conserving surgery and receiving whole-breast radiation, especially when the axillary lymph node is not suspicious during preoperative axillary ultrasound. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04303715 . Registered on March 11, 2020.

Impact of the ACOSOG Z0011 trial on surgical practice in Asian patients: trends in axillary surgery for breast cancer from a Korean Breast Cancer Registry analysis.

BACKGROUND: Since the publication of the Z0011 trial, practice-changing clinical guidelines for breast surgery have been developed. Although recent studies confirmed the feasibility of the Z0011 strategy in Asian populations, there has been no study on the trends of axillary surgery in Asian cohort. This study aimed to investigate the time trend of axillary surgery for breast cancer from a Korean Breast Cancer Registry to understand the impact of the Z0011 trial in Asian patients. METHODS: We collected prospectively constructed data from the nationwide Korean Breast Cancer Registry (KBCR). We identified patients who underwent sentinel node biopsy followed by breast-conserving surgery from 2011 to 2018 and were found to have pathological stage T1-2N1-3M0 disease. Regression analyses were performed to compare the downward trend of axillary lymph node dissection (ALND) in Korean cohort with that previously reported in a Dutch cohort. RESULTS: From KBCR data, 7478 patients met the inclusion criteria. The proportion of ALND significantly decreased from 2011 (76.6%) to 2018 (47.5%). Multivariate analysis revealed that earlier years at diagnosis, larger tumor size, and lymphatic invasion were associated with a higher odds ratio of performing ALND. Compared to the Dutch cohort, the downward trend of ALND in Korea was significantly more gradual (annual percent change: 37.2 vs. 5.8%, p < 0.001). CONCLUSIONS: This study demonstrated a downward trend of ALND in Korean patients with breast cancer. However, the rate of decrease was significantly slower than that in the Dutch cohort.

Obesity and breast cancer risk for pre- and postmenopausal women among over 6 million Korean women.

PURPOSE: To examine the association between obesity measured by body mass index (BMI) and waist circumference (WC) according to menopausal status in Korean women. METHODS: We identified 6,467,388 women, using the Korean National Health Insurance System Cohort. Cox-proportional hazard models were used to generate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for breast cancer risk in relation to BMI and WC. RESULTS: In postmenopausal women, the risk of breast cancer increased with BMI. Compared to women with a BMI of 18.5-23 kg/m two, the risk of invasive breast cancer was lower in patients with BMI < 18.5 (aHR 0.82, 95% CI 0.75-0.89), while it increased linearly in those with BMI 23-25 (1.11, 1.08-1.14), BMI 25-30 (1.28, 1.25-1.32), and BMI ≥ 30 (1.54,1.47-1.62). In contrast, the risk of breast cancer decreased with BMI in premenopausal women. Compared to women with a BMI of 18.5-23, the risk of IBC was similar in those with a BMI < 18.5 (1.02, 0.94-1.11) and BMI 23-25 (1.01, 0.97-1.05), but was significantly lower in those with a BMI 25-30 (0.95, 0.91-0.98) and BMI ≥ 30 (0.90, 0.82-0.98). A relative increase with BMI was less profound for carcinoma in situ in postmenopausal women, and a relative decrease was more profound in premenopausal women. An analysis using WC showed almost identical results. CONCLUSIONS: There was a positive relationship between obesity and breast cancer in postmenopausal women, and an inverse association in premenopausal women.

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 ).

Prognosis of BRCA1/2-negative breast cancer patients with HBOC risk factors compared with sporadic breast cancer patients without HBOC risk factors.

OBJECTIVE: Demands for genetic counseling with BRCA1/2 examination have markedly increased. Accordingly, the incidence of uninformative results on BRCA1/2 mutation status has also increased. Because most patients examined for BRCA1/2 mutation have a high risk of hereditary breast and/or ovarian cancer, many patients suffer psychological distress even when the BRCA1/2 result is negative. We compared oncological outcomes between BRCA1/2-negative breast cancer with high risk of hereditary breast and/or ovarian cancer and sporadic breast cancer without risk of hereditary breast and/or ovarian cancer. METHODS: The criteria for high risk for hereditary breast and/or ovarian cancer were defined as family history of breast and/or ovarian cancer in first- or second-degree relative, early onset breast cancer at <35 years old and bilateral breast cancer. Patients were matched maximally 1:3 into those who identified as negative for BRCA1/2 mutation with risk of hereditary breast and/or ovarian cancer (study group) and those who were not examined for BRCA1/2 mutation without risk for hereditary breast and/or ovarian cancer (control group). Matched variables were pathologic stage, estrogen receptor, progesterone receptor and human epidermal growth factor receptor-2 status. RESULTS: All matching variables were successfully matched. Median follow-up duration was 57.8 months. There was no significant difference between the groups in disease-free survival (log-rank P = 0.197); however, the study group showed significantly better overall survival and breast cancer-specific survival (both P < 0.0001). We conducted subgroup analysis in the middle-aged group (36-54) and showed no significant difference for disease-free survival (P = 0.072) but significantly better overall survival and breast cancer-specific survival in the study group (P = 0.002 and P < 0.0001). CONCLUSIONS: BRCA1/2-negative breast cancer patients who had hereditary breast and/or ovarian cancer risk factors showed similar disease-free survival and better overall survival and breast cancer-specific survival compared with those with sporadic breast cancer without hereditary breast and/or ovarian cancer risk factors.

Prediction of axillary pathologic response with breast pathologic complete response after neoadjuvant chemotherapy.

PURPOSE: Many breast cancer patients receive sentinel lymph node biopsy after neoadjuvant chemotherapy (NAC). We evaluated the axillary pathologic complete response (pCR) in relation to achievement of breast pCR. METHODS: We evaluated 1044 patients who were diagnosed with invasive breast cancer and were treated with NAC followed by curative surgery at the Samsung Medical Center between January 2008 and December 2016. The pathologic node-positive rates in breast pCR patients were compared for different breast cancer subtypes and clinical nodal stages. RESULTS: Axillary pCR was achieved in 51.9% of the patients after NAC. In this case, the axillary pCR was associated with a biologic subtype (P < 0.0001), initial clinical tumor stage (P < 0.0001), clinical nodal stage (P = 0.0071), and breast pCR (P < 0.0001). In particular, axillary pCR correlated more than 80% with breast pCR (87.1%) or clinical nodal stage N0 (81.0%). Patients with breast pCR had 96.4% axillary pCR in clinical nodal stage N0, 86.1% in N1, and 84.7% in N2/N3. CONCLUSION: Our study may help to predict node-positive rates in patients with breast pCR after NAC according to clinical node stage. Patients with a high probability of achieving pCR might be suitable candidates for more minimal surgery.

Prevalence and oncologic outcomes of BRCA 1/2 mutations in unselected triple-negative breast cancer patients in Korea.

PURPOSE: Triple-negative breast cancer (TNBC) accounts for 10-20% of all diagnosed BCs and it is enriched in BRCA1 mutation. Guidelines for Western countries suggest that BRCA 1/2 genetic testing should be done for patients with TNBC diagnosed less than 60 years, but there is lack of evidence supporting genetic testing in Asian populations. We determined the prevalence of germline BRCA 1/2 mutations among unselected Korean patients with TNBC and analyzed oncologic outcomes. METHODS: From among 1628 women with TNBC who underwent surgery at Samsung Medical Center (SMC) between Jul 2008 and Jan 2016, 999 samples were available in the SMC biobank for testing germline BRCA 1/2 mutations using next-generation DNA sequencing. RESULTS: Overall, 131 Korean patients (13.1%) had BRCA 1/2 mutations: 97 (9.7%) were in BRCA 1, and 35 (3.5%) were in BRCA 2. One patient had both BRCA 1 and BRCA 2 mutations. Overall, 68 distinct pathologic or likely pathogenic variants (43 BRCA1 and 25 BRCA2) were found. Among those diagnosed at ≤ 60 years, the prevalence of BRCA 1/2 mutation was 14.5%. The mean age of diagnosis of BRCA1/2 mutation carriers was significantly younger than that of non-carriers (45.6 vs. 50.1 years, p < 0.0001). The median follow-up duration was 53.6 months. There were no significant differences in disease-free survival, overall survival, or breast cancer-specific survival (p = 0.799, 0.092, and 0.124, respectively) between BRCA 1/2 carriers and non-carriers, although BRCA 1/2 carriers showed significantly worse contralateral breast cancer-free survival (p < 0.0001) than non-carriers. CONCLUSION: In unselected TNBC patients, we found BRCA 1/2 mutations in 13.1% of overall patients and 14.5% of patients ≤ 60 years. We suggest that Korean women with TNBC diagnosed at ≤ 60 years should be tested for BRCA1/2 mutation.

Only estrogen receptor "positive" is not enough to predict the prognosis of breast cancer.

PURPOSE: Beginning in 2018, biomarkers including estrogen receptor (ER) status were incorporated in the 8th AJCC staging system. ER expression levels were not considered in these changes. We hypothesized that the levels of ER expression could affect the prognosis of breast cancer. METHODS: A retrospective review was conducted to identify all female patients with invasive breast cancer between 2003 and 2012. ER negative (group I), weakly ER-positive (group II), and strongly ER-positive (group III) were defined as Allred total scores of 0-2, 3-5, and 6-8, respectively. We examined a multigene panel, designated the BCT score, which is a newly developed prognostic model for predicting the risk of a distant metastasis. RESULTS: Among the 4949 patients enrolled in this study, 1310 (26.5%), 361 (7.3%), and 3277 (66.2%) were categorized as group I, II, and III, respectively. Median F/U duration was 57.8 months. Compared to group III, patients in group II were younger, had larger tumors, and were also more likely to have PR-negative tumors, HER-2 amplification, high Ki-67, and high nuclear grade. Between group II and III, there was a significant difference in OS (P = 0.0764, 0.909, and 0.010, respectively). After adjusting for additional factors that may affect OS, the HR for OS showed higher in group II than in group III. The baseline median BCT score indicated that lower ER expression was associated with significantly higher BCT score (P < 0.0001) and significantly more likely to have high risk group (P < 0.0001) relative to higher levels of ER expression group. CONCLUSION: ER expression levels affect the prognosis of breast cancer. The risk for patients with weakly ER-positive breast cancer should not be underestimated.

Genetic Diagnosis before Surgery has an Impact on Surgical Decision in BRCA Mutation Carriers with Breast Cancer.

BACKGROUND: The first aim of our study was to evaluate surgical decision-making by BRCA mutation carriers with breast cancer based on the timing of knowledge of their BRCA mutation status. The second aim was to evaluate breast cancer outcome following surgical treatment. METHODS: This was a retrospective study of 164 patients diagnosed with invasive breast cancer, tested for BRCA mutation, and treated with primary surgery between 2004 and 2015 at Samsung Medical Center in Seoul, Korea. We reviewed types of surgery and timing of the BRCA test result. We compared surgical decision- making of BRCA carriers with breast cancer based on the timing of knowledge of their BRCA mutation status. RESULTS: Only 15 (9.1%) patients knew their BRCA test results before their surgery, and 149 (90.9%) knew the results after surgery. In patients with unilateral cancer, there was a significant difference between groups whose BRCA mutation status known before surgery and groups whose BRCA status unknown before surgery regarding the choice of surgery (p = 0.017). No significant difference was observed across surgery types of risk of ipsilateral breast tumor recurrence (p = 0.765) and contralateral breast cancer (p = 0.69). CONCLUSION: Genetic diagnosis before surgery has an impact on surgical decision choosing unilateral mastectomy or bilateral mastectomy in BRCA mutation carriers with breast cancer. Knowledge about BRCA mutation status after initial surgery led to additional surgeries for patients with BCS. Thus, providing genetic counseling and genetic testing before surgical choice and developing treatment strategies for patients with a high risk of breast cancer are important.

Different prognosis of young breast cancer patients in their 20s and 30s depending on subtype: a nationwide study from the Korean Breast Cancer Society.

PURPOSE: Numerous studies have demonstrated that breast cancer in young women (BCY) has unfavorable prognostic features and more unfavorable subtypes. However, few studies have evaluated the effect of subtype disparities on breast cancer prognosis by age, especially for BCY. We analyzed breast cancer mortality stratified by tumor subtype according to age among patients younger than 50 years. METHODS: Data from the Korean Breast Cancer Society Registry for patients diagnosed with invasive breast cancer when aged less than 50 years between 2003 and 2010 were reviewed retrospectively. RESULTS: We identified 30,793 patients with breast cancer who were eligible for analysis. Of these, 793 (2.6%) were aged 20-29 and 8926 (28.8%) were aged 30-39. Median follow-up duration was 84 months. Mean age was 42.4 years. Patients in their 20s were more likely to have cancer of advanced stage and higher nuclear grade, present with lymphovascular invasion, and have unfavorable subtypes. Patients in the 20s group showed worse prognosis. In multivariate analysis for overall survival (OS), the hazard ratio (HR) for patients in the 20s group was higher than that for the 30s and 40s groups, and patients with triple-negative breast cancer (TNBC) showed higher HR than patients with HER-2 or luminal subtype (all p < 0.0001). When stratified by subtype, luminal subtype showed significantly worse prognosis in the 20s group than the 30s and 40s groups, whereas HER-2 and TNBC subtypes showed no significant difference. CONCLUSION: Patients in their 20s with breast cancer had unfavorable characteristics and worse prognosis than patients in their 30s and 40s. When stratified by tumor subtype, patients in their 20s with luminal subtype of breast cancer showed worse prognosis than older patients, whereas HER-2 and TNBC subtypes showed no significant differences.