1.Impact of HER2-Low Status on Pathologic Complete Response and Survival Outcome Among Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy
Young Joo LEE ; Tae-Kyung YOO ; Sae Byul LEE ; Il Yong CHUNG ; Hee Jeong KIM ; Beom Seok KO ; Jong Won LEE ; Byung Ho SON ; Sei Hyun AHN ; Hyehyun JEONG ; Jae Ho JUNG ; Jin-Hee AHN ; Kyung Hae JUNG ; Sung-Bae KIM ; Hee Jin LEE ; Gyungyub GONG ; Jisun KIM
Journal of Breast Cancer 2025;28(1):11-22
Purpose:
This study analyzed the pathological complete response (pCR) rates, long-term outcomes, and biological features of human epidermal growth factor receptor 2 (HER2)-zero, HER2-low, and HER2-positive breast cancer patients undergoing neoadjuvant treatment.
Methods:
This single-center study included 1,667 patients who underwent neoadjuvant chemotherapy from 2008 to 2014. Patients were categorized by HER2 status, and their clinicopathological characteristics, chemotherapy responses, and recurrence-free survival (RFS) rates were analyzed.
Results:
Patients with HER2-low tumors were more likely to be older (p = 0.081), have a lower histological grade (p < 0.001), and have hormone receptor (HorR)-positive tumors (p < 0.001). The HER2-positive group exhibited the highest pCR rate (23.3%), followed by the HER2-zero (15.5%) and HER2-low (10.9%) groups. However, the pCR rate did not differ between HER2-low and HER2-zero tumors in the HorR-positive or HorR-negative subgroups.The 5-year RFS rates increased in the following order: HER2-low, HER2-positive, and HER2-zero (80.0%, 77.5%, and 74.5%, respectively) (log-rank test p = 0.017). A significant survival difference between patients with HER2-low and HER2-zero tumors was only identified in HorR-negative tumors (5-year RFS for HER2-low, 74.5% vs. HER2-zero, 66.0%; log-rank test p-value = 0.04). Multivariate survival analysis revealed that achieving a pCR was the most significant factor associated with improved survival (hazard ratio [HR], 4.279; p < 0.001).Compared with HER2-zero, the HRs for HER2-low and HER2-positive tumors were 0.787 (p = 0.042) and 0.728 (p = 0.005), respectively. After excluding patients who received HER2-targeted therapy, patients with HER2-low tumors exhibited better RFS than those with HER2-zero (HR 0.784, p = 0.04), whereas those with HER2-positive tumors exhibited no significant difference compared with those with HER2-low tumors (HR, 0.975; p = 0.953).
Conclusion
Patients with HER2-low tumors had no significant difference in pCR rate compared to HER2-zero but showed better survival, especially in HorR-negative tumors.Further investigation into biological differences is warranted.
2.Impact of HER2-Low Status on Pathologic Complete Response and Survival Outcome Among Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy
Young Joo LEE ; Tae-Kyung YOO ; Sae Byul LEE ; Il Yong CHUNG ; Hee Jeong KIM ; Beom Seok KO ; Jong Won LEE ; Byung Ho SON ; Sei Hyun AHN ; Hyehyun JEONG ; Jae Ho JUNG ; Jin-Hee AHN ; Kyung Hae JUNG ; Sung-Bae KIM ; Hee Jin LEE ; Gyungyub GONG ; Jisun KIM
Journal of Breast Cancer 2025;28(1):11-22
Purpose:
This study analyzed the pathological complete response (pCR) rates, long-term outcomes, and biological features of human epidermal growth factor receptor 2 (HER2)-zero, HER2-low, and HER2-positive breast cancer patients undergoing neoadjuvant treatment.
Methods:
This single-center study included 1,667 patients who underwent neoadjuvant chemotherapy from 2008 to 2014. Patients were categorized by HER2 status, and their clinicopathological characteristics, chemotherapy responses, and recurrence-free survival (RFS) rates were analyzed.
Results:
Patients with HER2-low tumors were more likely to be older (p = 0.081), have a lower histological grade (p < 0.001), and have hormone receptor (HorR)-positive tumors (p < 0.001). The HER2-positive group exhibited the highest pCR rate (23.3%), followed by the HER2-zero (15.5%) and HER2-low (10.9%) groups. However, the pCR rate did not differ between HER2-low and HER2-zero tumors in the HorR-positive or HorR-negative subgroups.The 5-year RFS rates increased in the following order: HER2-low, HER2-positive, and HER2-zero (80.0%, 77.5%, and 74.5%, respectively) (log-rank test p = 0.017). A significant survival difference between patients with HER2-low and HER2-zero tumors was only identified in HorR-negative tumors (5-year RFS for HER2-low, 74.5% vs. HER2-zero, 66.0%; log-rank test p-value = 0.04). Multivariate survival analysis revealed that achieving a pCR was the most significant factor associated with improved survival (hazard ratio [HR], 4.279; p < 0.001).Compared with HER2-zero, the HRs for HER2-low and HER2-positive tumors were 0.787 (p = 0.042) and 0.728 (p = 0.005), respectively. After excluding patients who received HER2-targeted therapy, patients with HER2-low tumors exhibited better RFS than those with HER2-zero (HR 0.784, p = 0.04), whereas those with HER2-positive tumors exhibited no significant difference compared with those with HER2-low tumors (HR, 0.975; p = 0.953).
Conclusion
Patients with HER2-low tumors had no significant difference in pCR rate compared to HER2-zero but showed better survival, especially in HorR-negative tumors.Further investigation into biological differences is warranted.
3.Impact of HER2-Low Status on Pathologic Complete Response and Survival Outcome Among Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy
Young Joo LEE ; Tae-Kyung YOO ; Sae Byul LEE ; Il Yong CHUNG ; Hee Jeong KIM ; Beom Seok KO ; Jong Won LEE ; Byung Ho SON ; Sei Hyun AHN ; Hyehyun JEONG ; Jae Ho JUNG ; Jin-Hee AHN ; Kyung Hae JUNG ; Sung-Bae KIM ; Hee Jin LEE ; Gyungyub GONG ; Jisun KIM
Journal of Breast Cancer 2025;28(1):11-22
Purpose:
This study analyzed the pathological complete response (pCR) rates, long-term outcomes, and biological features of human epidermal growth factor receptor 2 (HER2)-zero, HER2-low, and HER2-positive breast cancer patients undergoing neoadjuvant treatment.
Methods:
This single-center study included 1,667 patients who underwent neoadjuvant chemotherapy from 2008 to 2014. Patients were categorized by HER2 status, and their clinicopathological characteristics, chemotherapy responses, and recurrence-free survival (RFS) rates were analyzed.
Results:
Patients with HER2-low tumors were more likely to be older (p = 0.081), have a lower histological grade (p < 0.001), and have hormone receptor (HorR)-positive tumors (p < 0.001). The HER2-positive group exhibited the highest pCR rate (23.3%), followed by the HER2-zero (15.5%) and HER2-low (10.9%) groups. However, the pCR rate did not differ between HER2-low and HER2-zero tumors in the HorR-positive or HorR-negative subgroups.The 5-year RFS rates increased in the following order: HER2-low, HER2-positive, and HER2-zero (80.0%, 77.5%, and 74.5%, respectively) (log-rank test p = 0.017). A significant survival difference between patients with HER2-low and HER2-zero tumors was only identified in HorR-negative tumors (5-year RFS for HER2-low, 74.5% vs. HER2-zero, 66.0%; log-rank test p-value = 0.04). Multivariate survival analysis revealed that achieving a pCR was the most significant factor associated with improved survival (hazard ratio [HR], 4.279; p < 0.001).Compared with HER2-zero, the HRs for HER2-low and HER2-positive tumors were 0.787 (p = 0.042) and 0.728 (p = 0.005), respectively. After excluding patients who received HER2-targeted therapy, patients with HER2-low tumors exhibited better RFS than those with HER2-zero (HR 0.784, p = 0.04), whereas those with HER2-positive tumors exhibited no significant difference compared with those with HER2-low tumors (HR, 0.975; p = 0.953).
Conclusion
Patients with HER2-low tumors had no significant difference in pCR rate compared to HER2-zero but showed better survival, especially in HorR-negative tumors.Further investigation into biological differences is warranted.
4.Developing a Diagnostic Bundle for Bronchiectasis in South Korea: A Modified Delphi Consensus Study
Hayoung CHOI ; Hyun LEE ; Seung Won RA ; Jong Geol JANG ; Ji-Ho LEE ; Byung Woo JHUN ; Hye Yun PARK ; Ji Ye JUNG ; Seung Jun LEE ; Kyung-Wook JO ; Chin Kook RHEE ; Changwhan KIM ; Sei Won LEE ; Kyung Hoon MIN ; Yong-Soo KWON ; Deog Kyeom KIM ; Jin Hwa LEE ; Yong Bum PARK ; Eun Hee CHUNG ; Yae-Jean KIM ; Kwang Ha YOO ; Yeon-Mok OH
Tuberculosis and Respiratory Diseases 2022;85(1):56-66
Background:
Because the etiologies of bronchiectasis and related diseases vary significantly among different regions and ethnicities, this study aimed to develop a diagnostic bundle for bronchiectasis in South Korea.
Methods:
A modified Delphi method was used to develop expert consensus statements on a diagnostic bundle for bronchiectasis in South Korea. Initial statements proposed by a core panel, based on international bronchiectasis guidelines, were discussed in an online meeting and two email surveys by a panel of experts (≥70% agreement).
Results:
The study involved 21 expert participants, and 30 statements regarding a diagnostic bundle for bronchiectasis were classified as recommended, conditional, or not recommended. The consensus statements of the expert panel were as follows: A standardized diagnostic bundle is useful in clinical practice; diagnostic tests for specific diseases, including immunodeficiency and allergic bronchopulmonary aspergillosis, are necessary when clinically suspected; initial diagnostic tests, including sputum microbiology and spirometry, are essential in all patients with bronchiectasis, and patients suspected with rare causes such as primary ciliary dyskinesia should be referred to specialized centers.
Conclusion
Based on this Delphi survey, expert consensus statements were generated including specific diagnostic, laboratory, microbiological, and pulmonary function tests required to manage patients with bronchiectasis in South Korea.
5.Clinical Outcomes Following Letrozole Treatment according to Estrogen Receptor Expression in Postmenopausal Women: LETTER Study (KBCSG-006)
Sung Gwe AHN ; Seok Jin NAM ; Sei Hyun AHN ; Yongsik JUNG ; Heung Kyu PARK ; Soo Jung LEE ; Sung Soo KANG ; Wonshik HAN ; Kyong Hwa PARK ; Yong Lai PARK ; Jihyoun LEE ; Hyun Jo YOUN ; Jun Hyun KIM ; Youngbum YOO ; Jeong-Yoon SONG ; Byung Kyun KO ; Geumhee GWAK ; Min Sung CHUNG ; Sung Yong KIM ; Seo Heon CHO ; Doyil KIM ; Myung-Chul CHANG ; Byung In MOON ; Lee Su KIM ; Sei Joong KIM ; Min Ho PARK ; Tae Hyun KIM ; Jihyoung CHO ; Cheol Wan LIM ; Young Tae BAE ; Gyungyub GONG ; Young Kyung BAE ; Ahwon LEE ; Joon JEONG
Journal of Breast Cancer 2021;24(2):164-174
Purpose:
In this trial, we investigated the efficacy and safety of adjuvant letrozole for hormone receptor (HR)-positive breast cancer. Here, we report the clinical outcome in postmenopausal women with HR-positive breast cancer treated with adjuvant letrozole according to estrogen receptor (ER) expression levels.
Methods:
In this multi-institutional, open-label, observational study, postmenopausal patients with HR-positive breast cancer received adjuvant letrozole (2.5 mg/daily) for 5 years unless they experienced disease progression or unacceptable toxicity or withdrew their consent. The patients were stratified into the following 3 groups according to ER expression levels using a modified Allred score (AS): low, intermediate, and high (AS 3–4, 5–6, and 7–8, respectively). ER expression was centrally reviewed. The primary objective was the 5-year disease-free survival (DFS) rate.
Results:
Between April 25, 2010, and February 5, 2014, 440 patients were enrolled. With a median follow-up of 62.0 months, the 5-year DFS rate in all patients was 94.2% (95% confidence interval [CI], 91.8–96.6). The 5-year DFS and recurrence-free survival (RFS) rates did not differ according to ER expression; the 5-year DFS rates were 94.3% and 94.1%in the low-to-intermediate and high expression groups, respectively (p = 0.6), and the corresponding 5-year RFS rates were 95.7% and 95.4%, respectively (p = 0.7). Furthermore, 25 patients discontinued letrozole because of drug toxicity.
Conclusion
Treatment with adjuvant letrozole showed very favorable treatment outcomes and good tolerability among Korean postmenopausal women with ER-positive breast cancer, independent of ER expression.
6.Clinical Outcomes Following Letrozole Treatment according to Estrogen Receptor Expression in Postmenopausal Women: LETTER Study (KBCSG-006)
Sung Gwe AHN ; Seok Jin NAM ; Sei Hyun AHN ; Yongsik JUNG ; Heung Kyu PARK ; Soo Jung LEE ; Sung Soo KANG ; Wonshik HAN ; Kyong Hwa PARK ; Yong Lai PARK ; Jihyoun LEE ; Hyun Jo YOUN ; Jun Hyun KIM ; Youngbum YOO ; Jeong-Yoon SONG ; Byung Kyun KO ; Geumhee GWAK ; Min Sung CHUNG ; Sung Yong KIM ; Seo Heon CHO ; Doyil KIM ; Myung-Chul CHANG ; Byung In MOON ; Lee Su KIM ; Sei Joong KIM ; Min Ho PARK ; Tae Hyun KIM ; Jihyoung CHO ; Cheol Wan LIM ; Young Tae BAE ; Gyungyub GONG ; Young Kyung BAE ; Ahwon LEE ; Joon JEONG
Journal of Breast Cancer 2021;24(2):164-174
Purpose:
In this trial, we investigated the efficacy and safety of adjuvant letrozole for hormone receptor (HR)-positive breast cancer. Here, we report the clinical outcome in postmenopausal women with HR-positive breast cancer treated with adjuvant letrozole according to estrogen receptor (ER) expression levels.
Methods:
In this multi-institutional, open-label, observational study, postmenopausal patients with HR-positive breast cancer received adjuvant letrozole (2.5 mg/daily) for 5 years unless they experienced disease progression or unacceptable toxicity or withdrew their consent. The patients were stratified into the following 3 groups according to ER expression levels using a modified Allred score (AS): low, intermediate, and high (AS 3–4, 5–6, and 7–8, respectively). ER expression was centrally reviewed. The primary objective was the 5-year disease-free survival (DFS) rate.
Results:
Between April 25, 2010, and February 5, 2014, 440 patients were enrolled. With a median follow-up of 62.0 months, the 5-year DFS rate in all patients was 94.2% (95% confidence interval [CI], 91.8–96.6). The 5-year DFS and recurrence-free survival (RFS) rates did not differ according to ER expression; the 5-year DFS rates were 94.3% and 94.1%in the low-to-intermediate and high expression groups, respectively (p = 0.6), and the corresponding 5-year RFS rates were 95.7% and 95.4%, respectively (p = 0.7). Furthermore, 25 patients discontinued letrozole because of drug toxicity.
Conclusion
Treatment with adjuvant letrozole showed very favorable treatment outcomes and good tolerability among Korean postmenopausal women with ER-positive breast cancer, independent of ER expression.
7.The Impact of Androgen Receptor and Histone Deacetylase 1 Expression on the Prognosis of Ductal Carcinoma In Situ
Choong Man LEE ; Il Yong CHUNG ; Yangsoon PARK ; Keong Won YUN ; Hwi Gyeong JO ; Hye Jin PARK ; Hee Jin LEE ; Sae Byul LEE ; Hee Jeong KIM ; Beom Seok KO ; Jong Won LEE ; Byung Ho SON ; Sei Hyun AHN ; Jisun KIM
Journal of Breast Cancer 2020;23(6):610-621
Purpose:
Factors associated with invasive recurrence (REC) of ductal carcinoma in situ (DCIS) are less known. This study was aimed at identifying better biomarkers to predict the prognosis of DCIS.
Methods:
RNA extracted from formalin-fixed paraffin-embedded blocks of twenty-four pure DCIS cases was subjected to differential gene expression analysis. The DCIS cases were selected by matching age and estrogen receptor status. Sixteen REC-free and 8 invasive-REC cases with disease-free interval of > 5 years were analyzed. Immunohistochemistry (IHC) staining was used to validate sixty-one independent pure DCIS cases, including invasive-REC (n = 16) and REC-free (n = 45) cases.
Results:
Eight differentially expressed genes (DEGs) were statistically significant (log 2-fold change [FC] < –1 or > 1 and p < 0.001). Less than ½ fold expression of CUL1, androgen receptor (AR), RPS27A, CTNNB1, MAP3K1, PRKACA, GNG12, MGMT genes was observed in the REC group compared to the no evidence of disease group. AR and histone deacetylase 1 (HDAC1) genes were selected for external validation (AR: log 2-FC − 1.35, p < 0.001, and HDAC1: log 2-FC − 0.774, p < 0.001). External validation showed that the absence of AR and high HDAC1 expression were independent risk factors for invasive REC (hazard ratio [HR], 5.04; 95% confidence interval [CI], 1.24–20.4; p = 0.023 and HR, 3.07; 95% CI, 1.04–9.04; p = 0.042). High nuclear grade 3 was also associated with long-term invasive REC.
Conclusion
Comparative gene expression analysis of pure DCIS revealed 8 DEGs among recurring cases. External validation with IHC suggested that the absence of AR and overexpression of HDAC1 are associated with a greater risk of long-term invasive REC of pure DCIS.
8.Change in Estradiol Levels among Premenopausal Patients with Breast Cancer Treated Using Leuprolide Acetate 11.25 Milligrams 3-Month Depot and Tamoxifen
Young-jin LEE ; Zhen-Yu WU ; Hee jeong KIM ; Jong Won LEE ; Il Yong CHUNG ; Jisun KIM ; Sae Byul LEE ; Byung Ho SON ; Sung-Bae KIM ; Jae Ho JUNG ; Gyungyub GONG ; Sei-Hyun AHN ; BeomSeok KO
Journal of Breast Cancer 2020;23(5):553-559
The combination of luteinizing hormone-releasing hormone analogs (LHRHa) with tamoxifen is used as a standard postoperative adjuvant therapy in patients with hormone receptor-positive/premenopausal breast cancer. Long-acting LHRHa formulations offer advantages in terms of patient convenience. However, data on the effectiveness of the 3-month (3M) acting formulation are still insufficient. This study was performed on patients who received the 3M LHRHa after surgery. The serum estradiol (E2) and follicle-stimulating hormone levels were measured before surgery, and periodically after surgery. In total, 318 patients were included in the study and analyzed. The mean E2 level before surgery was 63.7 pg/mL, while the mean E2 level during the administration of 3M LHRHa was 4.9 pg/mL.None of the patients were menstruating and had E2 values above 30.0 pg/mL. It is thought that the 3M LHRHa formulation can suppress the ovarian function effectively and be safely used to improve compliance.
9.Prediction of Late Breast Cancer-Specific Mortality in Recurrence-Free Breast Cancer Survivors Treated for Five Years with Tamoxifen
Soo Yeon BAEK ; Ji Yeong KWON ; Young Joo LEE ; Sung chan GWARK ; Sae Byul LEE ; Jisun KIM ; Il Yong CHUNG ; Beom Seok KO ; Hee Jeong KIM ; Sung Bae KIM ; Seung Do AHN ; Gyungyub GONG ; Byung Ho SON ; Sei Hyun AHN ; Jong Won LEE
Journal of Breast Cancer 2019;22(3):387-398
PURPOSE: The extension of endocrine therapy beyond 5 years for recurrence-free survivors of breast cancer improves survival; however, the issue on how to clinically identify appropriate candidates remains controversial. This study aimed to identify prognostic factors for breast-cancer-specific mortality in patients who have had 5 years of tamoxifen treatment and categorize subgroups based on the risk of death using combinations of these prognostic factors to assist in the clinical decision to perform further endocrine therapy. METHODS: In total, 3,158 patients with breast cancer were enrolled. Breast cancer-specific survival rates after 5 years of tamoxifen treatment were calculated, and associated prognostic factors were analyzed using a Cox proportional-hazards model. RESULTS: An age extreme at diagnosis (i.e., < 40 or ≥ 60 years), tumor size > 2 cm, and positive lymphovascular invasion were robust independent prognostic factors for late breast cancer-specific death in tamoxifen-treated patients (hazard ratio [HR] = 2.162, 1.739, and 1.993; p = 0.001, 0.047, and 0.011, respectively). Lymph node metastasis and progesterone receptor negativity had borderline significance in this regard (HR = 1.741 and 1.638, p = 0.099 and 0.061). The study patients were classified into four groups according to the number of prognostic indicators, i.e., low, intermediate, high, and extremely high risk. The additional 5- and 10-year cumulative risks of breast cancer-specific death were 0.8% and 1.5% in the low-risk group, 0.9% and 3.9% in the intermediate-risk group, 1.3% and 7.3% in the high-risk group, and 4.8% and 13.8% in the extremely high-risk group, respectively. CONCLUSION: This new risk stratification system for late mortality in breast cancer can be used to identify the right candidates for extended endocrine therapy after 5 years of tamoxifen treatment.
Breast Neoplasms
;
Breast
;
Diagnosis
;
Humans
;
Lymph Nodes
;
Mortality
;
Neoplasm Metastasis
;
Prognosis
;
Receptors, Progesterone
;
Survival Rate
;
Survivors
;
Tamoxifen
10.Prescription Refill Gap of Endocrine Treatment from Electronic Medical Records as a Prognostic Factor in Breast Cancer Patients
Yura LEE ; Yu Rang PARK ; Ji Sung LEE ; Sae Byul LEE ; Il Yong CHUNG ; Byung Ho SON ; Sei Hyun AHN ; Jong Won LEE
Journal of Breast Cancer 2019;22(1):86-95
PURPOSE: Discontinuation of hormone therapy is known to lead to a poorer prognosis in breast cancer patients. We aimed to investigate the prescription gap as a prompt index of medication adherence by using prescription data extracted from patient electronic medical records. METHODS: A total of 5,928 patients diagnosed with invasive, non-metastatic breast cancer, who underwent surgery from January 1, 1997 to December 31, 2009, were enrolled retrospectively. The prescription data for 4.5 years of hormonal treatment and breast cancer-related events after treatment completion were analyzed. We examined the characteristics and prognoses of breast cancer in patients with and without a 4-week gap. RESULTS: Patients with a gap showed a significantly higher risk of breast cancer recurrence, distant metastasis, breast cancer-specific death, and overall death after adjustment (hazard ratio [HR], 1.389; 95% confidence interval [CI], 1.089–1.772; HR, 1.568; 95% CI, 1.158–2.123; HR, 2.108; 95% CI, 1.298–3.423; and HR, 2.102; 95% CI, 1.456–3.034, respectively). When patients were categorized based on gap summation, the lower third (160 days) and fourth (391 days) quartiles showed a significantly higher risk of distant metastasis (HR, 1.758; 95% CI, 1.186–2.606 and HR, 1.844; 95% CI, 1.262–2.693, respectively). CONCLUSION: A gap of > 4 weeks in hormonal treatment has negative effects on breast cancer prognosis, and can hence be used as a sentinel index of higher risk due to treatment non-adherence. Further evaluation is needed to determine whether the gap can be used as a universal index for monitoring the adherence to hormonal treatment.
Breast Neoplasms
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Breast
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Electronic Health Records
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Estrogen Antagonists
;
Humans
;
Medication Adherence
;
Neoplasm Metastasis
;
Prescriptions
;
Prognosis
;
Recurrence
;
Retrospective Studies

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