Age- and ethnic-driven molecular and clinical disparity of East Asian breast cancers.

BACKGROUND: Breast cancer (BC) is a complex disease with profound genomic aberrations. However, the underlying molecular disparity influenced by age and ethnicity remains elusive. METHODS: In this study, we aimed to investigate the molecular properties of 843 primary and metastatic BC patients enrolled in the K-MASTER program. By categorizing patients into two distinct age subgroups, we explored their unique molecular properties. Additionally, we leveraged large-scale genomic data from the TCGA and MSK-IMPACT studies to examine the ethnic-driven molecular and clinical disparities. RESULTS: We observed a high prevalence of PI3KCA mutations in K-MASTER HER2 + tumors, particularly in older patients. Moreover, we identified increased mutation rates in DNA damage response molecules, including ARID1A, MSH6, and MLH1. The K-MASTER patients were mainly comprised of triple-negative breast cancer (TNBC) and HER2-positive tumors, while the TCGA and MSK-IMPACT cohorts exhibited a predominance of hormone receptor-positive (HR +) subtype tumors. Importantly, GATA3 mutations were less frequently observed in East Asian patients, which correlated with poor clinical outcomes. In addition to characterizing the molecular disparities, we developed a gradient-boosting multivariable model to identify a new molecular signature that could predict the therapeutic response to platinum-based chemotherapy. CONCLUSIONS: Our findings collectively provide unprecedented insights into the significance of age and ethnicity on the molecular and clinical characteristics of BC patients.

Neoadjuvant Chemotherapy with Concurrent Letrozole for Estrogen Receptor-Positive and HER2-Negative Breast Cancer: An Open-Label, Single-Center, Nonrandomized Phase II Study (NeoCHAI).

The role of combining neoadjuvant endocrine therapy with conventional chemotherapy remains unclear; therefore, we conducted an open-label, single-center, nonrandomized phase II trial to assess the effect of this combination. Patients with previously untreated stage II or III HR-positive, HER2-negative breast cancer received concurrent letrozole 2.5 mg with standard neoadjuvant chemotherapy. The primary endpoint was pathologic complete response (pCR) at the time of surgery. We used Simon's minimax two-stage design; a pCR rate > 6% was necessary at the first stage to continue. Between November 2017 and November 2020, 53 women were enrolled in the first stage of the trial. Their median age was 49 years (range, 33-63), and 60% of them were premenopausal. Subsequently, 66% and 34% of patients with clinical stages II and III, respectively, were included; 93% had clinically node-positive disease. Two patients (4%) achieved pCR after neoadjuvant chemo-endocrine treatment, which did not satisfy the criteria for continuing to the second stage. The overall response rate was 83%. During the median follow-up of 53.7 months, the 3-year disease-free survival and overall survival rates were 87% and 98%, respectively. Neutropenia was the most common grade 3/4 adverse event (40%), but rarely led to febrile neutropenic episodes (4%). Myalgia (32%), nausea (19%), constipation (17%), heartburn (11%), oral mucositis (9%), and sensory neuropathy (9%) were frequently observed, but classified as grade 1 or 2. No deaths occurred during preoperative treatment. The addition of letrozole to standard neoadjuvant chemotherapy was safe and beneficial in terms of overall response rate, but did not provide a higher pCR rate in locally advanced HR-positive, HER2-negative breast cancer. Further research is needed to enhance neoadjuvant treatment strategies for this cancer subtype.

A phase 3 study (PATHWAY) of palbociclib plus tamoxifen in patients with HR-positive/HER2-negative advanced breast cancer.

Palbociclib combined with endocrine therapy is approved for treating patients with hormone-receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer; however, data on palbociclib combined with tamoxifen are limited. We investigated the efficacy and safety of palbociclib-tamoxifen in patients with HR+/HER2- advanced breast cancer. This double-blind phase 3 study included 184 women who were randomly assigned 1:1 to receive palbociclib-tamoxifen or placebo-tamoxifen. Pre/perimenopausal women also received goserelin. The primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included overall survival (OS) and safety. Median PFS was 24.4 months (95% confidence interval [CI], 13.1-32.4) with palbociclib-tamoxifen and 11.1 months (95% CI, 7.4-14.6) with placebo-tamoxifen (hazard ratio [HR], 0.60; 95% CI, 0.43-0.85; P = 0.002). Palbociclib-tamoxifen improved PFS in patients who were treated with first-line or second-line endocrine therapy and pre-, peri-, and postmenopausal patients. Though OS data are still immature (median not reached in both groups), an overall risk reduction of 27% (HR, 0.73; 95% CI, 0.44-1.21) with palbociclib-tamoxifen was observed at the time of PFS analysis. The most common grade 3/4 adverse event with palbociclib-tamoxifen was neutropenia (89.0% [none were febrile] versus 1.1% with placebo-tamoxifen). There were no deaths owing to adverse events in either group. Among patients with HR+/HER2- advanced breast cancer, palbociclib-tamoxifen resulted in significantly longer PFS than tamoxifen alone. Early OS data showed a trend favoring palbociclib-tamoxifen. Trial registration: ClinicalTrials.gov number, NCT03423199. Study registration date: February 06, 2018.

A 10-Gene Signature to Predict the Prognosis of Early-Stage Triple-Negative Breast Cancer.

Purpose: Triple-negative breast cancer (TNBC) is a particularly challenging subtype of breast cancer, with a poorer prognosis compared to other subtypes. Unfortunately, unlike luminal type cancers, there is no validated biomarker to predict the prognosis of patients with early-stage TNBC. Accurate biomarkers are needed to establish effective therapeutic strategies. Materials and Methods: In this study, we analyzed gene expression profiles of tumor samples from 184 TNBC patients (training cohort, n=76; validation cohort, n=108) using RNA sequencing. Results: By combining weighted gene expression, we identified a 10-gene signature (DGKH, GADD45B, KLF7, LYST, NR6A1, PYCARD, ROBO1, SLC22A20P, SLC24A3, and SLC45A4) that stratified patients by risk score with high sensitivity (92.31%), specificity (92.06%), and accuracy (92.11%) for invasive disease-free survival. The 10-gene signature was validated in a separate institution cohort and supported by meta-analysis for biological relevance to well-known driving pathways in TNBC. Furthermore, the 10-gene signature was the only independent factor for invasive disease-free survival in multivariate analysis when compared to other potential biomarkers of TNBC molecular subtypes and T-cell receptor ß diversity. 10-gene signature also further categorized patients classified as molecular subtypes according to risk scores. Conclusion: Our novel findings may help address the prognostic challenges in TNBC and the 10-gene signature could serve as a novel biomarker for risk-based patient care.

Clinical Application of Multimodal Sentinel Lymph Node Mapping Method in Patients with Breast Cancer Undergoing Neoadjuvant Chemotherapy: An Interim Analysis.

BACKGROUND: After neoadjuvant chemotherapy (NAC), the SLN identification rate is lower and has a higher false-negative rate than that at upfront surgery. This clinical trial aimed to confirm the effectiveness of sentinel lymph node (SLN) surgery by determining the lymph node identification rate using multimodal SLN marker methods in patients with advanced breast cancer undergoing NAC. PATIENTS AND METHODS: This clinical study is a prospective single-center randomized controlled trial involving patients with breast cancer receiving NAC. Patients are randomized (1:1:1) into arm A that involves the use of radioisotope (RI) plus indocyanine green fluorescence (ICG-F); arm B, RI plus vital dye; and, arm C, ICG-F plus vital dye. A total of 348 patients are needed. An interim analysis was performed on 50% of the patients enrolled. The primary outcome of this trial was the SLN identification rate. RESULTS: Among the 164 total patients (median age 51 years), T2 and N1 were the most common clinical stages. The identification rate of SLN was 95% in arm A, 92% in arm B, and 79% in arm C. To assess superior efficacy, the one-sided endpoint was set at α < 0.0056. Arms A and C showed a difference of 0.1597 in the detection rate (p = 0.0055). CONCLUSIONS: The use of ICG-F plus vital dye for SLNB was the least effective. The results show that the choice of tracer should be radioisotope in combination with one of the other tracers to have the highest SLN identification rate when SLNB cannot be implemented conventionally due to the circumstances of each institution.

Regional disparities in the availability of cancer clinical trials in Korea.

OBJECTIVES: Unequal access to cancer clinical trials is an important issue, given the potential benefits of participation for cancer patients. We evaluated regional disparities in access to cancer clinical trials in Korea. METHODS: From the Ministry of Food and Drug Safety database, we extracted 2,465 records of all cancer clinical trials approved between January 2012 and April 2023. To measure disparities in cancer clinical trial access, we calculated the ratio of clinical trials open to non-capital areas relative to those open to capital areas. We then analyzed temporal trends in this ratio, which we termed the trial geographical equity index (TGEI). RESULTS: Disparities in access to cancer clinical trials, as indicated by the TGEI, did not significantly improve during the study period (regression coefficient, 0.002; p=0.59). However, for phase II/III trials sponsored by global pharmaceutical companies, the TGEI improved significantly (regression coefficient, 0.021; p<0.01). In contrast, the TGEI deteriorated for trials initiated by investigators or those testing domestically developed therapeutics (regression coefficient, -0.015; p=0.05). Furthermore, the increasing trend of TGEI for phase II/III trials sponsored by global companies began to reverse after 2019, coinciding with the outbreak of coronavirus disease 2019 (COVID-19). CONCLUSIONS: Over the past decade, access to cancer clinical trials has improved in Korea, particularly for phase II/III trials evaluating therapeutics from global companies. However, this increase in accessibility has not extended to trials initiated by investigators or those assessing domestically developed therapeutics. Additionally, the impact of COVID-19 on disparities in clinical trial access should be closely monitored.

A nationwide real-world study for evaluation of effectiveness and safety of T-DM1 in patients with HER2-positive metastatic breast cancer in Korea (KCSG BR19-15).

Purpose: This study aimed to investigate clinical practices and factors related to the outcomes of T-DM1 use in patients with HER2-positive metastatic breast cancer (mBC). Methods: We included patients with HER2-positive mBC who received T-DM1 as a palliative therapy between August 2017 and December 2018. The safety and outcomes of T-DM1, including overall response rate (ORR), progression-free survival (PFS), and overall survival (OS), were evaluated. A Cox proportional hazards model was used to estimate the hazard ratio and 95% confidence interval (CI) for mortality or progression to HER2-positive mBC. Results: In total, 824 patients were enrolled during the study period. The mean age of patients was 58 years, and 516 (62.6%) patients relapsed after curative treatment. Excluding a history of endocrine therapy, 341 (41.4%) patients previously received none or first-line chemotherapy, 179 (21.7%) received second-line therapy, and 303 (36.9%) received third-or later-line chemotherapy before T-DM1 therapy. During a median follow-up of 16.8 months, the ORR was 35%, the median PFS was 6.6 months, and the median OS was not reached. The clinical factors associated with the hazard of progression were age (<65 years), poor performance status (⩾2), advanced line of palliative chemotherapy (⩾2), prior pertuzumab use, and treatment duration of palliative trastuzumab (<10 months). Common grade 3-4 adverse events were thrombocytopenia (n = 107, 13.2%), neutropenia (n = 23, 2.8%), anemia (n = 21, 2.6%), and elevated liver enzyme (n = 20, 2.5%). Hypokalemia (⩽3.0 mmol/L) and any-grade bleeding events occurred in 25 (3.1%) and 94 (22.6%) patients, respectively. Conclusion: This is the first nationwide real-world study of T-DM1 use in patients with HER2-positive mBC in Korea. The effectiveness and toxicity profiles of T-DM1 in real-world practice were comparable to those in randomized trials. Moreover, patient factors and previous anti-HER2 therapy could predict the outcomes of T-DM1 therapy.

Clinicopathological Factors Associated with Oncotype DX Risk Group in Patients with ER+/HER2- Breast Cancer.

Oncotype DX (ODX), a 21-gene assay, predicts the recurrence risk in early breast cancer; however, it has high costs and long testing times. We aimed to identify clinicopathological factors that can predict the ODX risk group and serve as alternatives to the ODX test. This retrospective study included 547 estrogen receptor-positive, human epidermal growth factor receptor 2-negative, and lymph node-negative breast cancer patients who underwent ODX testing. Based on the recurrence scores, three ODX risk categories (low: 0-15, intermediate: 16-25, and high: 26-100) were established in patients aged ≤50 years (n = 379), whereas two ODX risk categories (low: 0-25 and high: 26-100) were established in patients aged >50 years (n = 168). Factors selected for analysis included body mass index, menopausal status, type of surgery, and pathological and immunohistochemical features. The ODX risk groups showed significant association with histologic grade (p = 0.0002), progesterone receptor expression (p < 0.0001), Ki-67 (p < 0.0001), and p53 expression (p = 0.023) in patients aged ≤50 years. In patients aged >50 years, tumor size (p = 0.022), Ki-67 (p = 0.001), and p53 expression (p = 0.001) were significantly associated with the risk group. Certain clinicopathological factors can predict the ODX risk group and enable decision-making on adjuvant chemotherapy; these factors differ according to age.

Genomic analysis of plasma circulating tumor DNA in patients with heavily pretreated HER2 + metastatic breast cancer.

We explored accumulated genomic alterations in patients with heavily treated HER2 + metastatic breast cancer enrolled in the KCSG BR18-14/KM10B trial. Targeted sequencing was performed with circulating tumor DNAs (ctDNAs) collected before the treatment of 92 patients. ctDNAs collected at the time of disease progression from seven patients who had a durable response for > 12 months were also analyzed. Sixty-five genes were identified as pathogenic alterations in 99 samples. The most frequently altered genes were TP53 (n = 48), PIKCA (n = 21) and ERBB3 (n = 19). TP53 and PIK3CA mutations were significantly related with shorter progression free survival (PFS), and patients with a higher ctDNA fraction showed a worse PFS. The frequency of homologous recombination deficiency (HRD)-related gene mutations was higher than that in matched tumor tissues, and these mutations tended to be associated with shorter PFS. New pathogenic variants were found at the end of treatment in all seven patients, including BRCA2, VHL, RAD50, RB1, BRIP1, ATM, FANCA, and PIK3CA mutations. In conclusion, TP53 and PIK3CA mutations, as well as a higher ctDNA fraction, were associated with worse PFS with trastuzumab and cytotoxic chemotherapy. The enrichment of HRD-related gene mutations and newly detected variants in ctDNA may be related to resistance to treatment.

Establishment of Patient-Derived Organoids Using Ascitic or Pleural Fluid from Cancer Patients.

PURPOSE: Patient-derived tumor cells can be a powerful resource for studying pathophysiological mechanisms and developing robust strategies for precision medicine. However, establishing organoids from patient-derived cells is challenging because of limited access to tissue specimens. Therefore, we aimed to establish organoids from malignant ascites and pleural effusions. MATERIALS AND METHODS: Ascitic or pleural fluid from pancreatic, gastric, and breast cancer patients was collected and concentrated to culture tumor cells ex vivo. Organoids were considered to be successfully cultured when maintained for five or more passages. Immunohistochemical staining was performed to compare the molecular features, and drug sensitivity was assayed to analyze the clinical responses of original patients. RESULTS: We collected 70 fluid samples from 58 patients (pancreatic cancer, n=39; gastric cancer, n=21; and breast cancer, n=10). The overall success rate was 40%; however, it differed with types of malignancy, with pancreatic, gastric, and breast cancers showing 48.7%, 33.3%, and 20%, respectively. Cytopathological results significantly differed between successful and failed cases (p=0.014). Immunohistochemical staining of breast cancer organoids showed molecular features identical to those of tumor tissues. In drug sensitivity assays, pancreatic cancer organoids recapitulated the clinical responses of the original patients. CONCLUSION: Tumor organoids established from malignant ascites or pleural effusion of pancreatic, gastric, and breast cancers reflect the molecular characteristics and drug sensitivity profiles. Our organoid platform could be used as a testbed for patients with pleural and peritoneal metastases to guide precision oncology and drug discovery.

Risk Factors for Palbociclib-Induced Early Developing Neutropenia in Patients with Hormone Receptor-Positive Metastatic Breast Cancer.

PURPOSE: This study aimed to determine the risk factors for palbociclib-induced grade 4 or grade 3 neutropenia (NP) requiring dose reduction or delayed treatment in patients with HR+/HER2-metastatic breast cancer in the first 3 cycles (early grade 3/4 NP) and whether the early developing grade 3/4 NP affects progression-free survival. METHODS: A retrospective study using electronic medical records was conducted on patients who received palbociclib for metastatic breast cancer between January 2018 and August 2022. The early grade 3/4 NP risk factors were evaluated with univariate and multivariable logistic regression analyses. In addition, the Kaplan-Meier method was used to estimate the median progression-free survival (PFS) to analyze the effect of early grade 3/4 NP on treatment. RESULTS: Out of the 264 patients included in this study, 173 (65.6%) experienced early grade 3/4 NP. A total of four models were applied for multivariable analysis to identify early grade 3/4 NP-developing factors. Low baseline ANC, WBC, PLT, and BSA were significant risk factors for early grade 3/4 NP; baseline ANC < 3700/mm3, WBC < 6.30 × 109/mm3, PLT < 230 × 109/mm3, and BSA < 1.58 m2 increased the risk by approximately 4.0-fold, 3.7-4.0-fold, 2.1-fold, and 2.0-fold, respectively. Early grade 3/4 NP did not affect PFS (p = 0.710), although patients with early grade 3/4 NP had more frequent dose reductions or treatment delays. CONCLUSIONS: Based on the results, low baseline ANC, WBC, PLT, and BSA were associated with early grade 3/4 NP. Patients with risk factors require careful monitoring, and this study is expected to help predict NP, which may appear in early treatment.

Progranulin and Breast Cancer Mortality: 13-Year Follow-Up of a Cohort Study.

Background: We have reported that serum progranulin (PGRN) levels are clinically significant in predicting recurrence in patients with HR-positive breast cancer. The aim of the present study was to examine whether PGRN levels might be associated with breast cancer mortality. Methods: This was a cohort study of 695 newly diagnosed breast cancer patients who underwent curative surgery between 2001 and 2004. The relationship between breast cancer mortality and pre-operative serum PGRN levels in these patients with a median follow-up of 12.7 years was evaluated until May 2020. Results: A total of 118 (17%) deaths were identified in the cohort. According to the HR status, (10, 15, and 20)-year overall survival (OS) rates were (91.4, 81.1, and 75.9) % for HR-positive patients, and (76.5, 74.2, and 69.8) % for HR-negative patients, respectively (p = 0.003). Higher levels of PGRN were significantly associated with poor OS in the HR-positive group (p for trend = 0.001). In particular, hazard ratios for PGRN quartiles suggested a dose-response relationship, with the highest quartile having the worst OS in the HR-positive group (highest vs lowest: 15-year OS, (68.3 vs 90.0) %; 20-year OS, (62.3 vs 84.8) %, even after adjusting for age, tumor stage, and metabolic confounders. Conclusion: Pre-operative serum PGRN levels had clinical significance for predicting cancer mortality in breast cancer patients independent of tumor stage and metabolic parameters, especially in HR-positive tumors.

Surveillance of Symptom Burden Using the Patient-Reported Outcome Version of the Common Terminology Criteria for Adverse Events in Patients With Various Types of Cancers During Chemoradiation Therapy: Real-World Study.

BACKGROUND: Over 90% of patients with cancer experience 1 or more symptoms caused directly by cancer or its treatment. These symptoms negatively impact on the completion of planned treatment as well as patients' health-related quality of life (HRQoL). It often results in serious complications and even life-threatening outcomes. Thus, it has been recommended that surveillance of symptom burden should be performed and managed during cancer treatment. However, differences in symptom profiles in various patients with cancer have not been fully elucidated for use in performing surveillance in the real world. OBJECTIVE: This study aims to evaluate the burden of symptoms in patients with various types of cancers during chemotherapy or radiation therapy using the PRO-CTCAE (Patient-Reported Outcome Version of the Common Terminology Criteria for Adverse Events) and its impact on quality of life. METHODS: We performed a cross-sectional study of patients undergoing outpatient-based chemotherapy, radiation therapy, or both at the National Cancer Center at Goyang or at the Samsung Medical Center in Seoul, Korea between December 2017 and January 2018. To evaluate cancer-specific symptom burden, we developed 10 subsets for using the PRO-CTCAE-Korean. To measure HRQoL, we used the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). Participants answered questions prior to their clinic appointments on tablets. Multivariable linear regression was used to analyze symptoms based on cancer type and to evaluate the association between the PRO-CTCAE items and the EORTC QLQ-C30 summary score. RESULTS: The mean age (SD) of the patients was 55.0 (11.9) years, and 39.94% (540/1352) were male. Overall, symptoms in the gastrointestinal category were the most dominant in all cancers. Fatigue (1034/1352, 76.48%), decreased appetite (884/1352, 65.38%), and numbness and tingling (778/1352, 57.54%) were the most frequently reported. Patients reported more local symptoms caused by a specific cancer. In terms of nonsite-specific symptoms, patients commonly reported concentration (587/1352, 43.42%), anxiety (647/1352, 47.86%), and general pain (605/1352, 44.75%). More than 50% of patients with colorectal (69/127, 54.3%), gynecologic (63/112, 56.3%), breast (252/411, 61.3%), and lung cancers (121/234, 51.7%) experienced decreased libido, whereas 67/112 (59.8%) patients with gynecologic cancer and lymphoma/myeloma reported pain during sexual intercourse. Patients with breast, gastric, and liver cancers were more likely to have the hand-foot syndrome. Worsening PRO-CTCAE scores were associated with poor HRQoL (eg, fatigue: coefficient -8.15; 95% CI -9.32 to -6.97), difficulty in achieving and maintaining erection (coefficient -8.07; 95% CI -14.52 to -1.61), poor concentration (coefficient -7.54; 95% CI -9.06 to -6.01), and dizziness (coefficient -7.24; 95% CI -8.92 to -5.55). CONCLUSIONS: The frequency and severity of symptoms differed by cancer types. Higher symptom burden was associated with poor HRQoL, which suggests the importance of appropriate surveillance of PRO symptoms during cancer treatment. Considering patients had comprehensive symptoms, it is necessary to include a holistic approach in the symptom monitoring and management strategies based on comprehensive patient-reported outcome measurements.

Survival advantage of locoregional and systemic therapy in oligometastatic breast cancer: an international retrospective cohort study (OLIGO-BC1).

BACKGROUND: An international retrospective cohort study was conducted to clarify the survival advantage of combination therapy with locoregional and systemic therapy (ST) in oligometastatic breast cancer (BC). METHODS: Patients with oligometastatic BC diagnosed from 2007 to 2012 were enrolled in center hospitals in China, Korea and Japan. It was defined as a low-volume metastatic disease at up to five sites and not necessarily in the same organ. Cases with brain, pleural, peritoneal and pericardial metastases were excluded. The primary endpoint was overall survival (OS) from the initial diagnosis of oligometastases. OS was summarized using the Kaplan-Meier method. A multivariable Cox regression model was used to estimate the hazard ratio (HR) for clinicopathological factors. RESULTS: Among 1,295 cases registered from February 2018 to May 2019, 932 remained for analysis after the exclusion of unavailable cases and locoregional recurrence. One metastatic site was found in 400 cases, 2 in 243, 3 in 130, 4 in 86 and 5 in 73. At the median follow-up of 4.5 years, 5-year OS was 54.7% and 39.7% for 321 cases in the combination therapy group and 611 cases in the ST group, respectively. An adjusted HR was 0.66 (95% confidence interval: 0.55, 0.79). Some types of ST without chemotherapy alone, younger age, ECOG performance status 0, early-stage BC, non-triple negative subtype, fewer metastatic sites and longer duration of surgery to relapse were significantly favorable prognostic factors. CONCLUSION: Combination therapy may be considered for longer survival under some conditions in oligometastatic BC.

Impacts of Subtype on Clinical Feature and Outcome of Male Breast Cancer: Multicenter Study in Korea (KCSG BR16-09).

PURPOSE: The treatment of male breast cancer (MBC) has been extrapolated from female breast cancer (FBC) because of its rarity despite their different clinicopathologic characteristics. We aimed to investigate the distribution of intrinsic subtypes based on immunohistochemistry, their clinical impact, and treatment pattern in clinical practice through a multicenter study in Korea. MATERIALS AND METHODS: We retrospectively analyzed clinical data of 248 MBC patients from 18 institutions across the country from January 1995 to July 2016. RESULTS: The median age of MBC patients was 63 years (range, 25 to 102 years). Among 148 intrinsic subtype classified patients, 61 (41.2%), 44 (29.7%), 29 (19.5%), and 14 (9.5%) were luminal A, luminal B, human epidermal growth factor receptor 2, and triple-negative breast cancer, respectively. Luminal A subtype showed trends for superior survival compared to other subtypes. Most hormone receptor-positive patients (166 patients, 82.6%) received adjuvant endocrine treatment. Five-year completion of adjuvant endocrine treatment was associated with superior disease-free survival (DFS) in patients classified with an intrinsic subtype (hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04 to 0.49; p=0.002) and in all patients (HR, 0.16; 95% CI, 0.05 to 0.54; p=0.003). CONCLUSION: Distribution of subtypes of MBC was similar to FBC and luminal type A was most common. Overall survival tended to be improved for luminal A subtype, although there was no statistical significance. Completion of adjuvant endocrine treatment was associated with prolonged DFS in intrinsic subtype classified patients. MBC patients tended to receive less treatment. MBC patients should receive standard treatment according to guidelines as FBC patients.

Androgen Receptor as a Predictive Marker for Pathologic Complete Response in Hormone Receptor-Positive and HER-2-Negative Breast Cancer with Neoadjuvant Chemotherapy.

PURPOSE: This study investigated pathological complete response (pCR) according to androgen receptor (AR) in breast cancer patients undergoing neoadjuvant chemotherapy and estimated the relationship between AR expression and clinicopathological factors. Materials and Methods: We identified 624 breast cancer patients who underwent surgery after neoadjuvant chemotherapy at the National Cancer Center in Goyang, Korea from April 2016 to October 2019. We retrospectively collected the clinicopathologic information and AR expression results and analyzed the data according to cancer stage, hormonal receptor (HR) status, human epidermal growth factor receptor 2 (HER2) status, tumor subtype, and pCR. RESULTS: Among the 624 breast cancer patients, 529 (84.8%) were AR-positive (AR+) patients and 95 (15.2%) were AR-negative (AR-) patients. AR+ patients showed more estrogen receptor (ER) positivity, progesterone receptor (PR) positivity, HER2-positivity, and HR-positive and HER2-negative (HR+/HER2-) subtype. The rate of pCR was 31.4% (196/624). AR- patients had a significantly higher rate of pCR than AR+ patients (AR- 43.2% vs. AR+ 29.3%, p=0.007). The tumor factors associated with pCR were early stage, histologic grade 3, ER-negative, PR-negative, AR-negative, HER2-positive, and high Ki-67 values. In univariable analysis, AR+ significantly decreased the state of pCR (odds ratio, 0.546; 95% confidence interval, 0.349 to 0.853; p=0.008). According to tumor subtype, AR- tumor showed higher pCR rate in HR+/HER2- subtype (AR- 28.6% vs. AR+ 7.3%, p=0.022). CONCLUSION: AR expression is predominant in the HR+/HER2- subtype. AR- is significantly associated with the pCR rate in breast cancer patients, especially within HR+/HER2- subtype. When determining neoadjuvant chemotherapy for the HR+/HER2- subtype, AR expression can be considered as a pCR predictive marker.

Phase II study to investigate the efficacy of trastuzumab biosimilar (Herzuma®) plus treatment of physician's choice (TPC) in patients with heavily pretreated HER-2+ metastatic breast cancer (KCSG BR 18-14/KM10B).

We investigated the efficacy and safety of a trastuzumab biosimilar, Herzuma®, in combination with treatment of physician's choice (TPC) in patients with HER2+ metastatic breast cancer (MBC) who had failed at least two HER2 directed chemotherapies.