Hyung Seok Park

This study investigated the feasibility of sentinel lymph node biopsy (SLNB) after neoadjuvant systemic therapy (NAST) in patients with initially high nodal burden. 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. 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). 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.

Despite increased awareness and availability of genetic testing for hereditary breast and ovarian cancer (HBOC) syndrome for over 20 years, there is still significant underuse of cascade genetic testing among at-risk relatives. This scoping review synthesized evidence regarding psychosocial barriers and facilitators of family communication and/or uptake of cascade genetic testing in relatives from HBOC families. Search terms included ‘hereditary breast and ovarian cancer’and ‘cascade genetic testing’for studies published from 2012–2022. Through searching common databases, and manual search of references, 480 studies were identified after excluding duplications. Each article was reviewed by two researchers independently and 20 studies were included in the final analysis. CASP, RoBANS 2.0, RoB 2.0, and MMAT were used to assess the quality of included studies. A convergent data synthesis method was …

Recent studies have reported the effectiveness of immune checkpoint blockade (ICB) therapy in breast cancer patients. However, only a subset of patients benefits from ICB therapy due to various immunosuppressive mechanisms. The development of personalized predictive models for the anti-tumor immune response is essential to broaden the indication of ICB therapy. Here, we suggest a novel model platform using a co-culture system with patient tumor-derived organoids and matched immune cells to predict the immune response of individual patients. We successfully established fifty-nine cases of patient-derived breast cancer organoids with matched peripheral blood mononuclear cells (PBMCs) (subtype: Luminal A, 18.6%; Luminal B, 28.8%; Triple-negative breast cancer, 35.6%; HER2-positive, 17.0%). Three rapidly proliferating organoids (one Luminal B and two TNBC organoids) were selected to develop …

ASO Visual Abstract: Oncologic Outcomes in Nipple-Sparing Mastectomy with Immediate Reconstruction and Total Mastectomy with Immediate Reconstruction in Women with Breast Cancer: A Machine Learning Analysis ASO Visual Abstract: Oncologic Outcomes in Nipple-Sparing Mastectomy with Immediate Reconstruction and Total Mastectomy with Immediate Reconstruction in Women with Breast Cancer: A Machine Learning Analysis Ann Surg Oncol. 2024 Feb 8. doi: 10.1245/s10434-024-14982-x. Online ahead of print. Authors Jun-Ho Cho # 1 , Jung Mi Park # 2 , Hyung Seok Park 3 , Hye Jin Kim 1 , Dong-Min Shin 1 , Jee Ye Kim 1 , Seho Park 1 , Seung Il Kim 1 , Byeong-Woo Park 1 Affiliations 1 Department of Surgery, Yonsei University College of Medicine, Seoul, Republic of Korea. 2 Department of Biostatistics and Computing, Graduate School, Yonsei University, Seoul, Korea. 3 Department of Surgery, …

PurposeFrequent neutropenia hinders uninterrupted palbociclib treatment in patients with hormone receptor (HR)–positive breast cancer. We compared the efficacy outcomes in multicenter cohorts of patients with metastatic breast cancer (mBC) receiving palbociclib following conventional dose modification or limited modified schemes for afebrile grade 3 neutropenia.Materials and MethodsPatients with HR-positive, human epidermal growth factor receptor 2–negative mBC (n= 434) receiving palbociclib with letrozole as first-line therapy were analyzed and classified based on neutropenia grade and afebrile grade 3 neutropenia management as follows: group 1 (maintained palbociclib dose, limited scheme), group 2 (dose delay or reduction, conventional scheme), group 3 (no afebrile grade 3 neutropenia event), and group 4 (grade 4 neutropenia event). The primary and secondary endpoints were progression-free …

ResultsBaseline characteristics. Among 2,403 breast cancer patients in the Korean Hereditary Breast Cancer (KOHBRA) study, more than a quarter, 676 (28.13%) patients, had mutations that were classified as VUS. Simultaneous mutations of BRCA1 and BRCA2 were observed in 55 (55/676, 8.14%) patients. Of the 676 subjects, 278 had a VUS in BRCA1, and 453 patients had a VUS in BRCA2 (Fig. 1). refSNP (RS) numbers were reviewed for 262 and 440 subjects with BRCA1 and BRCA2 mutations, respectively.Reclassification using public databases. Table 1 shows the reclassification results for VUS according to the ClinVar database. We classified the results into four groups: benign/likely benign, VUS, conflicting interpretations of pathogenicity, and pathogenic/likely pathogenic. Benign/likely benign was the most common reclassification for both BRCA1 and BRCA2 VUSs. Table 2 shows the rank of VUS genes based on the number of patients.

A patient-derived organoid (PDO) is an in vitro three-dimensional model which shows similar features in phenotypic and genetic aspects with primary tissue from patients. PDOs are useful for preclinical studies including drug sensitivity tests of tumors from individual patients as well as development of novel targeted agents. Collectively, PDOs are recently introduced as an emerging platform for personalized medicine. We obtained a total of 100 surgical specimens from 100 patients with breast cancer at the Yonsei Cancer Center, Severance Hospital, Seoul, Korea. One of the tissue specimens was acquired from a breast cancer patient-derived xenograft model. We dissociated the tissues and isolated breast cancer primary tumor cells from the samples, and then the cells were cultured in basement membrane-like matrix in 3D manner with growth medium with supplements. We defined successful establishment of …

Background Low-pass whole-genome sequencing (LP-WGS)–based circulating tumor DNA (ctDNA) analysis is a versatile tool for somatic copy number aberration (CNA) detection, and this study aims to explore its clinical implication in breast cancer. Methods We analyzed LP-WGS ctDNA data from 207 metastatic breast cancer (MBC) patients to explore prognostic value of ctDNA CNA burden and validated it in 465 stage II-III triple-negative breast cancer (TNBC) patients who received neoadjuvant chemotherapy in phase III PEARLY trial (NCT02441933). The clinical implication of locus level LP-WGS ctDNA profiling was further evaluated. Results We found that a high baseline ctDNA CNA burden predicts poor overall survival and progression-free survival of MBC patients. The post hoc analysis of the PEARLY trial showed that a high baseline ctDNA CNA …

BackgroundThe molecular selective pressure on anti-tumor therapy drives lineage plasticity in several cancer types to develop drug resistance. The subtype conversion from hormone receptor-positive to triple-negative breast cancer (TNBC) subtype fuels endocrine resistance and disease aggressiveness. In this study, we analyzed mechanisms of luminal to basal (LB) subtype conversion by clinical sample sequencing and molecular study.MethodsIn the 359 metastatic breast cancer (MBC) patients with matched primary and recurrent tumor biopsies in Yonsei Cancer Center MBC database, we identified 31 MBC patients with LB subtype change. For MBC patients with available tissues, we performed whole-exome sequencing (WES) and RNA-seq of MBC patients with LB subtype conversion (n= 15) and the luminal to luminal (LL) subtype maintenance (n= 13), respectively. We manipulated genetic factors related to …

In a leader in BJS, Monica Morrow 1 commented that robot-assisted nipple-sparing mastectomy (RNSM) has emerged from Europe and Asia. She was concerned by the experience with robot-assisted and laparoscopic hysterectomy, which were adopted widely on the basis of retrospective studies, but stopped on the basis of an RCT revealing that open surgery was associated with better disease-free survival (DFS) and overall survival (OS). She commented that there was currently no evidence of superior cosmetic outcomes and oncological outcomes of RNSM, and that this procedure was highly unlikely to be cost-effective. She therefore concluded that RNSM currently has no role outside clinical trials.The Korea Robot–Endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG) 2 reported early experiences with 11 surgeons at eight institutions that had appropriate training. They showed rapid learning …

BackgroundAxillary evaluation is unnecessary for pure ductal carcinoma in situ (DCIS); however, it is performed because of the risk of upstaging to invasive cancer. We assessed the role of intraoperative frozen section (IOF) biopsy in reducing invasive cancer upstaging and axillary evaluation in preoperative DCIS patients.MethodsWe reviewed patients with preoperative DCIS who underwent breast-conserving surgery (BCS) with IOF biopsy. Positive IOF biopsy findings were defined as the presence of invasive or micro-invasive cancer. The IOF biopsy and permanent pathology findings were compared.ResultsSeventy-eight patients underwent BCS with IOF biopsy. Six patients showed positive IOF biopsy findings; five of these patients showed concordant permanent pathology findings. Sentinel lymph node biopsy (SLNB) was positive in one patient. Thirteen patients with invasive breast cancer were missed by IOF …

PurposeFew studies have reported on patient prognosis according to residual cancer burden after neoadjuvant chemotherapy (NAC). Herein, we evaluated the survival of patients based on residual disease after NAC to identify subpopulations with distinct prognoses.MethodsWe retrospectively reviewed 728 patients treated with NAC from 2010 to 2017. Patients were divided into four subgroups depending on post-surgical residual disease according to the staging system: pathological complete response (pCR) (ypT0/TisN0), minimal residual disease (MRD) (ypT1mi/T1aN0 or ypT0/Tis ypN0i+/N1mic), node-only pCR (≥ ypT1b ypN0), and breast-only pCR (ypT0/Tis ≥ ypN1a). Clinicopathological characteristics and survival outcomes were analyzed by adjusting for factors affecting survival.ResultsOverall, 50.4% (n = 367) of patients achieved pCR, with the MRD group accounting for 16.5% (n = 120). Although age …

BackgroundRobotic surgical systems enable surgeons to perform precise movement in the surgical field using high-resolution 3D vision and flexible robotic instruments. We aimed to evaluate the feasibility and safety of performing axillary lymph node dissection using a robotic surgical system in patients with node-positive breast cancer.MethodsThirty-two women with breast cancer who underwent robot-assisted nipple-sparing mastectomy (RNSM) and level I/II axillary lymph node dissection were analyzed. Patients were divided into two groups: RNSM with conventional axillary lymph node dissection (CALND) vs. RNSM with robotic axillary lymph node dissection (RALND). Clinicopathological features and surgical outcomes were analyzed.ResultsThe median age of the patients was 44 (range 20–59) years. Eleven patients underwent RALND. None of the clinicopathologic features differed between the two groups …

Nipple-sparing mastectomy (NSM) is used to improve cosmetic outcomes while maintaining oncological safety in patients with early breast cancer; however, NSM requires a higher level of skill and workload than mastectomy and is associated with long, visible scars. Robotic surgical systems reduce surgeon workload and facilitate precise surgery. Considering the increasing support of robot-assisted NSM (RNSM), this paper aims to discuss the current controversies based on the research findings reported thus far.

BackgroundThis study used a single-institution cohort, the Severance dataset, validated the results by using the surveillance, epidemiology, and end results (SEER) database, adjusted with propensity-score matching (PSM), and analyzed by using a machine learning method.To determine whether the 5-year, disease-free survival (DFS) and overall survival (OS) of patients undergoing nipple-sparing mastectomy (NSM) with immediate breast reconstruction (IBR) are not inferior to those of women treated with total mastectomy/skin-sparing mastectomy (TM/SSM).MethodsThe Severance dataset enrolled 611 patients with early, invasive breast cancer from 2010 to 2017. The SEER dataset contained data for 485,245 patients undergoing TM and 14,770 patients undergoing NSM between 2000 and 2018. All patients underwent mastectomy and IBR. Intraoperative, frozen-section biopsy for the retro-areolar tissue was …

BackgroundCyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have been established as a standard treatment for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC); however, predictive biomarkers with translational relevance have not yet been elucidated.MethodsData from postmenopausal women who received the CDK4/6 inhibitor palbociclib and letrozole for HR-positive, HER2-negative ABC from tertiary referral centers were analyzed (N = 221; exploratory cohort). Pre- and on-treatment neutrophil-to-lymphocyte ratio (NLR) and derived NLR (dNLR; neutrophil/[leukocyte-neutrophil]) were correlated with survival outcomes. Data from the PALOMA-2 (NCT01740427) and PALOMA-3 studies (NCT01942135) involving patients treated with endocrine treatment with or without palbociclib were also analyzed (validation cohort …

BackgroundRobotic 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 …

Background:This study aimed to analyze the novel operative outcomes of breast mound reconstruction followed by robot-assisted mastectomy in retrospective reviewMethod:Patients who underwent nipple-sparing mastectomy with a robotic device (Da Vinci Xi) and immediate prosthetic reconstruction prepectorally via lateral incision from June 2018 to July 2019 were enrolled. Patient characteristics, complications, and satisfaction via BREAST-Q were analyzed. The surgical technique was described in detail.Results:Thirty-nine cases, including 7 bilateral cases (total 46 breasts), underwent robot-assisted nipple-sparing mastectomy followed by immediate prosthetic implant reconstruction prepectorally. The median patient age was 46.63 years (range: 21–63 years). The mean operation time for each prepectoral breast mound reconstruction using the direct-to-implant technique was 126.55 min. Overall satisfaction of …

PurposeLymphovascular invasion (LVI) is a well-known poor prognostic factor for early breast cancer. However, the effect of LVI on breast cancer subtype and node status remains unknown. In this study, we aimed to evaluate the clinical significance of LVI on the recurrence and long-term survival of patients with early breast cancer by comparing groups according to the subtype and node status.MethodsWe retrospectively reviewed the medical records of 4554 patients with breast cancer who underwent breast cancer surgery between January 2010 and December 2017. The primary endpoints were disease-free survival (DFS) and overall survival (OS). Univariate and multivariate analyses were performed to identify prognostic factors related to the DFS and OS according to the nodal status and breast cancer subtype.ResultsDuring a follow-up period of 94 months, the median OS and DFS were 92 and 90 months …

ObjectiveMammographic density is an independent risk factor for breast cancer that can change after neoadjuvant chemotherapy (NCT). This study aimed to evaluate percent changes in volumetric breast density (ΔVbd%) before and after NCT measured automatically and determine its value as a predictive marker of pathological response to NCT.Materials and MethodsA total of 357 patients with breast cancer treated between January 2014 and December 2016 were included. An automated volumetric breast density (Vbd) measurement method was used to calculate Vbd on mammography before and after NCT. Patients were divided into three groups according to ΔVbd%, calculated as follows: Vbd (post-NCT− pre-NCT)/pre-NCT Vbd× 100 (%). The stable, decreased, and increased groups were defined as-20%≤ ΔVbd%≤ 20%, ΔVbd%<-20%, and ΔVbd%> 20%, respectively. Pathological complete response …