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Featured researches published by Guiyun Sohn.


Journal of Medical Internet Research | 2014

Daily collection of self-reporting sleep disturbance data via a smartphone app in breast cancer patients receiving chemotherapy: a feasibility study.

Yul Ha Min; Jong Won Lee; Yong-Wook Shin; Min-Woo Jo; Guiyun Sohn; Jae Ho Lee; Guna Lee; Kyung Hae Jung; Joohon Sung; Beom Seok Ko; Jong Han Yu; Hee Jeong Kim; Byung Ho Son; Sei Hyun Ahn

Background Improvements in mobile telecommunication technologies have enabled clinicians to collect patient-reported outcome (PRO) data more frequently, but there is as yet limited evidence regarding the frequency with which PRO data can be collected via smartphone applications (apps) in breast cancer patients receiving chemotherapy. Objective The primary objective of this study was to determine the feasibility of an app for sleep disturbance-related data collection from breast cancer patients receiving chemotherapy. A secondary objective was to identify the variables associated with better compliance in order to identify the optimal subgroups to include in future studies of smartphone-based interventions. Methods Between March 2013 and July 2013, patients who planned to receive neoadjuvant chemotherapy for breast cancer at Asan Medical Center who had access to a smartphone app were enrolled just before the start of their chemotherapy and asked to self-report their sleep patterns, anxiety severity, and mood status via a smartphone app on a daily basis during the 90-day study period. Push notifications were sent to participants daily at 9 am and 7 pm. Data regarding the patients’ demographics, interval from enrollment to first self-report, baseline Beck’s Depression Inventory (BDI) score, and health-related quality of life score (as assessed using the EuroQol Five Dimensional [EQ5D-3L] questionnaire) were collected to ascertain the factors associated with compliance with the self-reporting process. Results A total of 30 participants (mean age 45 years, SD 6; range 35-65 years) were analyzed in this study. In total, 2700 daily push notifications were sent to these 30 participants over the 90-day study period via their smartphones, resulting in the collection of 1215 self-reporting sleep-disturbance data items (overall compliance rate=45.0%, 1215/2700). The median value of individual patient-level reporting rates was 41.1% (range 6.7-95.6%). The longitudinal day-level compliance curve fell to 50.0% at day 34 and reached a nadir of 13.3% at day 90. The cumulative longitudinal compliance curve exhibited a steady decrease by about 50% at day 70 and continued to fall to 45% on day 90. Women without any form of employment exhibited the higher compliance rate. There was no association between any of the other patient characteristics (ie, demographics, and BDI and EQ5D-3L scores) and compliance. The mean individual patient-level reporting rate was higher for the subgroup with a 1-day lag time, defined as starting to self-report on the day immediately after enrollment, than for those with a lag of 2 or more days (51.6%, SD 24.0 and 29.6%, SD 25.3, respectively; P=.03). Conclusions The 90-day longitudinal collection of daily self-reporting sleep-disturbance data via a smartphone app was found to be feasible. Further research should focus on how to sustain compliance with this self-reporting for a longer time and select subpopulations with higher rates of compliance for mobile health care.


Breast Cancer Research | 2015

Metformin increases survival in hormone receptor-positive, HER2-positive breast cancer patients with diabetes

Hee Jeong Kim; Hyunwook Kwon; Jong Won Lee; Hwa Jung Kim; Sae Byul Lee; Hee Sung Park; Guiyun Sohn; Yura Lee; Beom Seok Koh; Jong Han Yu; Byung Ho Son; Sei Hyun Ahn

IntroductionMetformin use has recently been observed to decrease both the rate and mortality of breast cancer. Our study was aim to determine whether metformin use is associated with survival in diabetic breast cancer patients by breast cancer subtype and systemic treatment.MethodsData from the Asan Medical Center Breast Cancer Database from 1997 to 2007 were analyzed. The study cohort comprised 6,967 nondiabetic patients, 202 diabetic patients treated with metformin, and 184 diabetic patients that did not receive metformin. Patients who were divided into three groups by diabetes status and metformin use were also divided into four subgroups by hormone receptor and HER2-neu status.ResultsIn Kaplan-Meier analysis, the metformin group had a significantly better overall and cancer specific survival outcome compared with non metformin diabetic group (P <0.005 for both). There was no difference in survival between the nondiabetic and metformin groups. In multivariate analysis, Compared with metformin group, patients who did not receive metformin tended to have a higher risk of metastasis with HR 5.37 (95 % CI, 1.88 to 15.28) and breast cancer death with HR 6.51 (95 % CI, 1.88 to 15.28) on the hormone receptor-positive and HER2-negative breast cancer. The significant survival benefit of metformin observed in diabetic patients who received chemotherapy and endocrine therapy (HR for disease free survival 2.14; 95 % CI 1.14 to 4.04) was not seen in diabetic patients who did not receive these treatments.ConclusionPatients receiving metformin treatment when breast cancer diagnosis show a better prognosis only if they have hormone receptor-positive, HER2-positive tumors. Metformin treatment might provide a survival benefit when added to systemic therapy in diabetic patients.


Journal of Medical Internet Research | 2016

Depression Screening Using Daily Mental-Health Ratings from a Smartphone Application for Breast Cancer Patients

Junetae Kim; Sanghee Lim; Yul Ha Min; Yong-Wook Shin; Byungtae Lee; Guiyun Sohn; Kyung Hae Jung; Jae Ho Lee; Byung Ho Son; Sei Hyun Ahn; Soo-Yong Shin; Jong Won Lee

Background Mobile mental-health trackers are mobile phone apps that gather self-reported mental-health ratings from users. They have received great attention from clinicians as tools to screen for depression in individual patients. While several apps that ask simple questions using face emoticons have been developed, there has been no study examining the validity of their screening performance. Objective In this study, we (1) evaluate the potential of a mobile mental-health tracker that uses three daily mental-health ratings (sleep satisfaction, mood, and anxiety) as indicators for depression, (2) discuss three approaches to data processing (ratio, average, and frequency) for generating indicator variables, and (3) examine the impact of adherence on reporting using a mobile mental-health tracker and accuracy in depression screening. Methods We analyzed 5792 sets of daily mental-health ratings collected from 78 breast cancer patients over a 48-week period. Using the Patient Health Questionnaire-9 (PHQ-9) as the measure of true depression status, we conducted a random-effect logistic panel regression and receiver operating characteristic (ROC) analysis to evaluate the screening performance of the mobile mental-health tracker. In addition, we classified patients into two subgroups based on their adherence level (higher adherence and lower adherence) using a k-means clustering algorithm and compared the screening accuracy between the two groups. Results With the ratio approach, the area under the ROC curve (AUC) is 0.8012, indicating that the performance of depression screening using daily mental-health ratings gathered via mobile mental-health trackers is comparable to the results of PHQ-9 tests. Also, the AUC is significantly higher (P=.002) for the higher adherence group (AUC=0.8524) than for the lower adherence group (AUC=0.7234). This result shows that adherence to self-reporting is associated with a higher accuracy of depression screening. Conclusions Our results support the potential of a mobile mental-health tracker as a tool for screening for depression in practice. Also, this study provides clinicians with a guideline for generating indicator variables from daily mental-health ratings. Furthermore, our results provide empirical evidence for the critical role of adherence to self-reporting, which represents crucial information for both doctors and patients.


PLOS ONE | 2017

Interaction between body mass index and hormone-receptor status as a prognostic factor in lymph-node-positive breast cancer

Il Yong Chung; Jong Won Lee; Ji Sung Lee; Yu Rang Park; Yul Ha Min; Yura Lee; Tae In Yoon; Guiyun Sohn; Sae Byul Lee; Jisun Kim; Hee Jeong Kim; Beom Seok Ko; Byung Ho Son; Sei Hyun Ahn

The aim of this study was to determine the relationship between the body mass index (BMI) at a breast cancer diagnosis and various factors including the hormone-receptor, menopause, and lymph-node status, and identify if there is a specific patient subgroup for which the BMI has an effect on the breast cancer prognosis. We retrospectively analyzed the data of 8,742 patients with non-metastatic invasive breast cancer from the research database of Asan Medical Center. The overall survival (OS) and breast-cancer-specific survival (BCSS) outcomes were compared among BMI groups using the Kaplan-Meier method and Cox proportional-hazards regression models with an interaction term. There was a significant interaction between BMI and hormone-receptor status for the OS (P = 0.029), and BCSS (P = 0.013) in lymph-node-positive breast cancers. Obesity in hormone-receptor-positive breast cancer showed a poorer OS (adjusted hazard ratio [HR] = 1.51, 95% confidence interval [CI] = 0.92 to 2.48) and significantly poorer BCSS (HR = 1.80, 95% CI = 1.08 to 2.99). In contrast, a high BMI in hormone-receptor-negative breast cancer revealed a better OS (HR = 0.44, 95% CI = 0.16 to 1.19) and BCSS (HR = 0.53, 95% CI = 0.19 to 1.44). Being underweight (BMI < 18.50 kg/m2) with hormone-receptor-negative breast cancer was associated with a significantly worse OS (HR = 1.98, 95% CI = 1.00–3.95) and BCSS (HR = 2.24, 95% CI = 1.12–4.47). There was no significant interaction found between the BMI and hormone-receptor status in the lymph-node-negative setting, and BMI did not interact with the menopause status in any subgroup. In conclusion, BMI interacts with the hormone-receptor status in a lymph-node-positive setting, thereby playing a role in the prognosis of breast cancer.


Journal of Breast Cancer | 2017

Clinicopathologic Characteristics of Pregnancy-Associated Breast Cancer: Results of Analysis of a Nationwide Breast Cancer Registry Database

Yun Gyoung Kim; Ye Won Jeon; Byung Kyun Ko; Guiyun Sohn; Eun-Kyu Kim; Byung-In Moon; Hyun Jo Youn; Hyun-Ah Kim

Purpose This study aimed to evaluate the clinicopathological characteristics of pregnancy-associated breast cancer (PABC) in comparison with non-pregnancy associated breast cancer (non-PABC). Methods A total of 344 eligible patients with PABC were identified in the Korean Breast Cancer Society Registry database. PABC was defined as ductal carcinoma in situ, invasive ductal carcinoma, or invasive lobular carcinoma diagnosed during pregnancy or within 1 year after the birth of a child. Patients with non-PABC were selected from the same database using a 1:2 matching method. The matching variables were operation, age, and initial stage. Results Patients with PABC had significantly lower survival rates than patient with non-PABC (10-year survival rate: PABC, 76.4%; non-PABC, 85.1%; p=0.011). PABC patients had higher histologic grade and were more frequently hormone receptor negative than non-PABC patients. Being overweight (body mass index [BMI], ≥23 kg/m2), early menarche (≤13 years), late age at first childbirth (≥30 years), and a family history of breast cancer were more common in the PABC group than in the non-PABC group. Multivariate analysis showed the following factors to be significantly associated with PABC (vs. non-PABC): early menarche (odds ratio [OR], 2.165; 95% confidence interval [CI], 1.566–2.994; p<0.001), late age at first childbirth (OR, 2.446; 95% CI, 1.722–3.473; p<0.001), and being overweight (OR, 1.389; 95% CI, 1.007–1.917; p=0.045). Conclusion Early menarche, late age at first childbirth, and BMI ≥23 kg/m2 were more associated with PABC than non-PABC.


Psycho-oncology | 2016

Patient reporting pain intensity immediately after surgery can be associated with underlying depression in women with breast cancer.

Yoo Seok Kim; Hyuigyung Do; Jong Won Lee; Jae-Sim Jeong; Yong Wook Shin; Kikyoung Yi; Jisun Kim; Sae Byul Lee; Guiyun Sohn; Nuri Yang; Youngkyung Oh; Leeyoung Kim; Yeonhee Kim; Jong Han Yu; Beom Seok Ko; Hee Jeong Kim; Byung Ho Son; Sei Hyun Ahn

The aims of this study were to determine the prevalence of severe, definite depression symptoms, as measured using the Center for Epidemiological Studies Depression Scale (CES‐D), and the association between high CES‐D scores (i.e., ≥25) and sociodemographic and perioperative factors during perioperative period.


Journal of Breast Cancer | 2015

Concurrent Gonadotropin-Releasing Hormone Agonist Administration with Chemotherapy Improves Neoadjuvant Chemotherapy Responses in Young Premenopausal Breast Cancer Patients

Hee Jeong Kim; Tae-In Yoon; Hee Dong Chae; Jeong Eun Kim; Eun Young Chae; Jong Han Yu; Guiyun Sohn; Beom Seok Ko; Jong Won Lee; Byung Ho Son; Sei Hyun Ahn

Purpose This study aimed to determine the oncologic efficacy of gonadotropin-releasing hormone (GnRH) agonist treatment concurrent with chemotherapy in a neoadjuvant setting. Methods A retrospective analysis was performed on 332 cases of invasive breast cancer in patients who were <40 years old at diagnosis and received GnRH agonists concurrent with neoadjuvant chemotherapy (GnRH agonist group) or neoadjuvant chemotherapy alone (neochemotherapy-alone group) from December 2010 to September 2014. Pathologic complete response rates (pCR) and Ki-67 changes were evaluated between the two groups. Results Median age was 32±3.9 and 36±3.0 years in the GnRH agonist group and neochemotherapy-alone group, respectively (p<0.001). After adjustment for tumor size, grade, lymph node metastasis, hormone receptor (HR) status, and chemotherapy regimen, the GnRH agonist group exhibited a higher pCR rate with an odds ratio (OR) of 2.98 (95% confidence interval [CI], 1.37-6.34) and a greater decrease in Ki-67 expression after treatment (p=0.05) than the neochemotherapy-alone group. For HR-negative tumors, the GnRH agonist group showed a higher pCR rate (multivariate OR, 3.50; 95% CI, 1.37-8.95) and a greater decrease in Ki-67 expression (p=0.047). For HR-positive breast cancer, the pCR rate, change in Ki-67 index, and clinical response were higher, and preoperative endocrine prognostic index scores were lower, in the GnRH agonist group, but these did not reach statistical significance. Conclusion Concurrent administration of GnRH agonists during neoadjuvant chemotherapy improved pCR rates and suppressed Ki-67 expression, especially in HR-negative tumors.


Journal of Breast Cancer | 2014

Reliability of the Percent Density in Digital Mammography with a Semi-Automated Thresholding Method

Guiyun Sohn; Jong Won Lee; Sung Won Park; Jihoon Park; Jiyoung Woo; Hwa Jung Kim; Hee Jung Shin; Hak Hee Kim; Kyung Hae Jung; Joohon Sung; Seung Wook Lee; Byung Ho Son; Sei-Hyun Ahn

Purpose The reliability of the quantitative measurement of breast density with a semi-automated thresholding method (Cumulus™) has mainly been investigated with film mammograms. This study aimed to evaluate the intrarater reproducibility of percent density (PD) by Cumulus™ with digital mammograms. Methods This study included 1,496 craniocaudal digital mammograms from the unaffected breast of breast cancer patients. One rater reviewed each mammogram and estimated the PD using the Cumulus™ method. All images were reassessed by the same rater 1 month later without reference to the previously assigned values. The repeatability of the PD was evaluated by an intraclass correlation coefficient (ICC). All patients were grouped based on their body mass index (BMI), age, family history of breast cancer, breastfeeding history and breast area (calculated with Cumulus™), and subgroup analysis for the ICC of each group was performed. All patients were categorized by their Breast Imaging Reporting and Data System (BI-RADS) density pattern, and the mean and standard deviation of the PD by each BI-RADS categories were compared. Results The ICC for the PD was 0.94, indicating excellent repeatability. The discrepancy between the paired PD values ranged from 0 to 23.93, with an average of 3.90 (standard deviation=3.39). The subgroup ICCs for the PD ranged from 0.88 to 0.96, indicating excellent reliability in all subgroups regardless of patient variables. The ICCs of the PD for the high-risk (BI-RADS 3 and 4) and low-risk (BI-RADS 1 and 2) groups were 0.90 and 0.88, respectively. Conclusion This study suggests that PD calculated with digital mammograms has an acceptable reliability regardless of patient age, BMI, family history of breast cancer, breastfeeding history, breast size, and BI-RADS density pattern.


Journal of Breast Cancer | 2018

Chronological Improvement in Survival of Patients with Breast Cancer: A Large-Scale, Single-Center Study

Sae Byul Lee; Guiyun Sohn; Jisun Kim; Il Yong Chung; Hee Jeong Kim; Beom Seok Ko; Jong Won Lee; Byung Ho Son; Sung-Bae Kim; Sei-Hyun Ahn

Purpose This study aimed to chronologically evaluate survival of patients with breast cancer in Korea and investigate the observed changes during the last 20 years. We also sought to determine factors that may influence outcomes and changes in the duration of survival over time. Methods We retrospectively analyzed a total of 10,988 patients with breast cancer who were treated at our institution between January 1993 and December 2008. We divided the study period into three periods (P1, 1993–1997; P2, 1998–2002; and P3, 2003–2008). We retrospectively reviewed the collected data from the Asan database, including age at diagnosis, clinical manifestations, pathology report, surgical methods, types of adjuvant treatment modalities, type of recurrence, and follow-up period. Results At a median follow-up of 8.2 years, we observed that survival outcomes have improved recently. The 5-year breast cancer-specific survival (BCSS) rate also increased from 82.8% in P1 to 92.6% in P3 (p<0.001). The survival rate in patients with tumors at each stage increased in similar patterns in all patients, and, remarkably, there was a significant survival improvement in patients with stage III breast cancer (P1 vs. P3: 5-year BCSS, 57.4% vs. 80.0%, p<0.001). The time period was a significant prognostic factor in multivariate analysis (P1 vs. P2: hazard ratio [HR], 0.83, p=0.035; P1 vs. P3: HR, 0.75, p=0.015). Conclusion The study results suggest an improvement in breast cancer survival in Korea, which is consistent with the development of treatments and early detection.


Clinical Breast Cancer | 2018

Comparing Accuracy of Mammography and Magnetic Resonance Imaging for Residual Calcified Lesions in Breast Cancer Patients Undergoing Neoadjuvant Systemic Therapy

Eunhae Um; Ji-Won Kang; SaeByul Lee; Hee Jeong Kim; Tae in Yoon; Guiyun Sohn; Il Yong Chung; Jisun Kim; Jong Won Lee; Byung Ho Son; Sei Hyun Ahn; Beom Seok Ko

Background Neoadjuvant systemic therapy (NST) is performed to increase the rate of breast‐conserving surgery in advanced breast cancer patients. Although magnetic resonance imaging (MRI) is accurate in predicting residual cancer, if calcification remains, the issue of whether to perform the surgery on the basis of the residual tumor prediction range in mammography (MMG) or MRI has not yet been elucidated. This study aimed to estimate the accuracy of predicting residual tumor after NST for residual microcalcification on mammographic and enhancing lesion on MRI. Patients and Methods This was a single‐center, retrospective study. We included breast cancer patients who underwent NST, had microcalcifications in the post‐NST MMG, and underwent surgery from January 2, 2013 to December 30, 2014 at Asan Medical Center. Patients with post‐NST MMG as well as MRI were included. Final pathologic tumor size with histopathology and biomarker status were obtained postoperatively. Results In total, 151 patients were included in this study. Overall, MRI correlated better than MMG in predicting the tumor size (intraclass correlation coefficient [ICC], 0.769 vs. 0.651). For hormone receptor (HR)‐positive (HR+)/HER2− subtype, MMG had higher correlation than MRI (ICC = 0.747 vs. 0.575). In HR− subtype, MRI had a strong correlation with pathology (HR−/HER2+ or triple negative (TN), ICC = 0.939 vs. 0.750), whereas MMG tended to overestimate the tumor size (HR−/HER2+ or TN, ICC = 0.543 vs. 0.479). Conclusion Post‐NST residual microcalcifications on MMG have a lower correlation with residual tumor size than MRI. Other than HR+/HER2− subtype, the extent of calcifications on preoperative evaluation might not be accurate in evaluating the residual extent of the tumor after NST. Micro‐Abstract In breast cancer, the extent of the malignant‐looking calcification usually does not decrease after neoadjuvant systemic treatment, making it difficult to know the extent of the tumor in surgical planning. Comparing different imaging tools for such cases, magnetic resonance imaging was shown to be more precise in predicting residual cancer, especially in the hormone receptor‐negative subtype.

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