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Featured researches published by Yi-Jun Kim.


Radiation oncology journal | 2015

Prognostic analysis of uterine cervical cancer treated with postoperative radiotherapy: importance of positive or close parametrial resection margin.

Yi-Jun Kim; Kyung-Ja Lee; Kyung Ran Park; Ji-Young Kim; Wonguen Jung; Rena Lee; Seung Cheol Kim; Hye Sung Moon; Woong Ju; Yun Hwan Kim; Jihae Lee

Purpose To analyze prognostic factors for locoregional recurrence (LRR), distant metastasis (DM), and overall survival (OS) in cervical cancer patients who underwent radical hysterectomy followed by postoperative radiotherapy (PORT) in a single institute. Materials and Methods Clinicopathologic data of 135 patients with clinical stage IA2 to IIA2 cervical cancer treated with PORT from 2001 to 2012 were reviewed, retrospectively. Postoperative parametrial resection margin (PRM) and vaginal resection margin (VRM) were investigated separately. The median treatment dosage of external beam radiotherapy (EBRT) to the whole pelvis was 50.4 Gy in 1.8 Gy/fraction. High-dose-rate vaginal brachytherapy after EBRT was given to patients with positive or close VRMs. Concurrent platinum-based chemoradiotherapy (CCRT) was administered to 73 patients with positive resection margin, lymph node (LN) metastasis, or direct extension of parametrium. Kaplan-Meier method and log-rank test were used for analyzing LRR, DM, and OS; Cox regression was applied to analyze prognostic factors. Results The 5-year disease-free survival was 79% and 5-year OS was 91%. In univariate analysis, positive or close PRM, LN metastasis, direct extension of parametrium, lymphovascular invasion, histology of adenocarcinoma, and chemotherapy were related with more DM and poor OS. In multivariate analysis, PRM and LN metastasis remained independent prognostic factors for OS. Conclusion PORT after radical hysterectomy in uterine cervical cancer showed excellent OS in this study. Positive or close PRM after radical hysterectomy in uterine cervical cancer correlates with poor prognosis even with CCRT. Therefore, additional treatments to improve local control such as radiation boosting need to be considered.


The Breast | 2017

Radiation therapy for malignant phyllodes tumor of the breast: An analysis of SEER data

Yi-Jun Kim; Kyubo Kim

PURPOSE Malignant phyllodes tumor of the breast (MPTB) accounts for less than 1% of whole breast neoplasm. Surgery is regarded as the primary treatment of choice in patients with MPTB, but the necessity of postoperative radiation therapy (RT) has been a subject of debate. Our aim was to evaluate effects of postoperative RT for MPTB using a large population database. METHODS Using the Surveillance, Epidemiology, and End Results Program (SEER) database (1983-2013), clinico-pathologic prognostic factors were evaluated. Postoperative RT, tumor extent, grade, and lymph node (LN) metastasis were included in the analysis. Univariate and multivariate Cox proportional hazards regressions were performed to evaluate prognostic power of variables on cancer specific survival (CSS). RESULTS A total of 1974 patients with MPTB were reviewed. Of these, 825 (42%) and 1149 (58%) patients underwent mastectomy and breast conserving surgery (BCS), respectively. In each group, 130 (16%) and 122 (11%) patients received postoperative RT. For patients with adverse risk factors including high grade and large tumor size, postoperative RT was more likely to be performed. In multivariate analysis, age, ethnicity, tumor size, tumor extension and LN status were correlated with prognosis in mastectomy group, while postoperative RT did not affect CSS. In BCS group, age and grade were significant prognostic factors on CSS, meanwhile postoperative RT did not impact CSS in multivariate analysis. CONCLUSION Although patients with more adverse prognostic factors underwent postoperative RT, RT groups were not inferior to non-RT group on CSS regardless of surgery (mastectomy or BCS).


British Journal of Radiology | 2015

Pulmonary nodule size evaluation with chest tomosynthesis and CT: a phantom study.

S. S. Shim; Yu Whan Oh; K. A. Kong; Y. J. Ryu; Yi-Jun Kim; D. H. Jang

OBJECTIVE We compared digital tomosynthesis (TOMO) and chest CT in terms of assessing the sizes of nodules located in zones where evaluation by simple radiography is limited. METHODS A total of 48 images comprising phantom nodules of four sizes in six different locations were used. Nodule size measurement errors for measurements using TOMO and CT images compared with the actual size from each observer were calculated. The inter- and intraobserver repeatability of the measured values and the agreement between the two techniques were assessed using the method described by Bland and Altman. RESULTS The mean measurement errors for all of the nodules and four observers were -0.84 mm [standard deviation (SD), 0.60 mm] on TOMO and -0.18 mm (SD, 0.71 mm) on CT images. The mean measurement errors for the different observers ranged from -1.11 to -0.55 mm for TOMO and from -0.39 to 0.08 mm for CT. Assessing the agreement between nodule size measurements using TOMO and CT resulted in mean measurement errors of -0.65 mm, with a 95% limit of agreement of -2.53 to 1.22 mm for comparison of TOMO with CT. CONCLUSION Our results suggest that nodule sizes obtained using TOMO and chest CT are comparable, even for nodules located in areas where the size measurement is limited on simple radiography. ADVANCES IN KNOWLEDGE TOMO and CT can be used interchangeably, even for nodules located in a blind area on simple radiography.


Cancer Research and Treatment | 2003

The Effect of ZD 1839 (Iressa(R)) in the Treatment of Refractory Non Small Cell Lung Cancer.

Yong Tai Kim; Chun Choo Kim; Jin Hee Sohn; Sung-Ji Park; Yu Nc; Yi-Jun Kim; Sung Kyoung Kim; Jung Min Chang; Kil Dong Kim; Kee Yang Chung; J. Kim

PURPOSE The aim of this study was to evaluate the efficacy and the safety of ZD 1839 (Iressa(R)) as a 3rd or 4th line chemotherapy regimen in NSCLC patients who are refractory to a previous chemotherapy regimen. MATERIALS AND METHODS Twenty-five patients who were refractory to previous chemotherapy were selected for this study. The eligible patients had an ECOG performance status of 0 to 2, and an appropriate end organ function. ZD 1839 (Iressa(R))250 mg/d was orally administered until the patients experienced disease progression or unacceptable toxicity. RESULTS Twenty-five patients were analyzed. The median age of the patients was 57 years. The response rate was 12.0% with partial responses in 3 patients. Fourteen patients (56%) remained in the stable disease state and 8 patients progressed. The median overall survival was 9.0 months (95% CI 6.7~11.2). The median progression free survival was 3 months (95% CI 2.2~3.8). Hematological toxicities of grade 3 or 4 neutropenia, anemia and thrombocytopenia were absent. Non-hematological toxicities were grade 2 or 3 skin rashes in 10 (40.0%) patients and 1 (4.0%) patient and grade 3 nausea in 3 (12.0%) patients. No patient failed to continue chemotherapy due to any drug-related adverse events. CONCLUSION The results suggest that ZD 1839 (Iressa(R)) monotherapy is effective and tolerable as a 3rd or 4th line salvage treatment for NSCLC patients refractory to previous chemotherapy regimens.


Cancer Research and Treatment | 2018

Omitting Adjuvant Radiotherapy for Hormone Receptor‒Positive Early-Stage Breast Cancer in Old Age: A Propensity Score Matched SEER Analysis

Yi-Jun Kim; Kyung Hwan Shin; Kyubo Kim

Purpose The purpose of this study was to investigate the non-inferiority of omitting radiotherapy (RT) after breast-conserving surgery (BCS) for hormone receptor (HR)‒positive T1N0 breast cancer in elderly women. Materials and Methods From 2004 to 2014, HR-positive T1N0 breast cancer patients aged 50 years or older and receiving BCS were retrieved from the Surveillance, Epidemiology, and End Results 18 database. After propensity score matching between the no-RT and RT groups, univariate and multivariate analyses were performed. Identified prognostic factors were used to stratify the risk groups. In each risk group, 10-year cancer-specific survival (CSS) rates were compared between the no-RT and RT groups. Results After propensity score matching, the numbers of patients in the no-RT and RT groups were both 18,586. For patients who satisfied both a tumor size of 1-10 mm and a tumor grade of 1-2, omitting RT did not decrease the CSS rate at any age group, ranging from ≥ 50 to ≥ 85 years; for patients aged ≥ 50 years, the 10-year CSS rates in the no-RT and RT groups were 97.2% and 96.8%, respectively (adjusted hazard ratio, 0.862; p=0.312). However, for patients with a tumor size of 11-20 mm or tumor grade of 3-4, RT significantly increased the CSS rate irrespective of age. Conclusion RT after BCS for HR-positive T1N0 breast cancer in elderly women might be omitted without causing a decrease in the CSS rate, but only in patients who satisfy both a small tumor size (≤ 10 mm) and low tumor grade (1-2).


Radiation oncology journal | 2017

Value of imaging study in predicting pelvic lymph node metastases of uterine cervical cancer

Wonguen Jung; Kyung Park; Kyung-Ja Lee; Kyubo Kim; Jihae Lee; Songmi Jeong; Yi-Jun Kim; Ji-Young Kim; Hai-Jeon Yoon; Byung-Chul Kang; Hae Soo Koo; Sun Hee Sung; Min-Sun Cho; Sanghui Park

Purpose To evaluate the diagnostic accuracy of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) in predicting pelvic lymph node (LN) metastases in patients with cervical cancer. Materials and Methods From January 2009 to March 2015, 114 patients with FIGO stage IA1-IIB uterine cervical cancer who underwent hysterectomy with pelvic lymphadenectomy and took CT, MRI, and PET/CT before surgery were enrolled in this study. The criteria for LN metastases were a LN diameter ≥1.0 cm and/or the presence of central necrosis on CT, a LN diameter ≥1.0 cm on MRI, and a focally increased FDG uptake on PET/CT. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for pelvic LN metastases were estimated. Results The sensitivity, specificity, PPV, NPV, and accuracy for detection of pelvic LN metastases were 51.4%, 85.9%, 41.3%, 90.1%, and 80.3% for CT; 24.3%, 96.3%, 56.3%, 86.8%, and 84.6% for MRI; and 48.6%, 89.5%, 47.4%, 90.0%, and 82.9% for PET/CT, respectively. The sensitivity of PET/CT and CT was higher than that of MRI (p=0.004 and p= 0.013, respectively). The specificity of MRI was higher than those of PET/CT and CT (p=0.002 and p=0.001, respectively). The difference of specificity between PET/CT and CT was not statistically significant (p=0.167). Conclusion These results indicate that preoperative CT, MRI, and PET/CT showed low to moderate sensitivity and PPV, and moderate to high specificity, NPV, and accuracy. More efforts are necessary to improve sensitivity of imaging modalities in order to predict pelvic LN metastases.


British Journal of Radiology | 2017

Role of adjuvant radiotherapy for localized extrahepatic bile duct cancer

Yi-Jun Kim; Kyubo Kim; Seog Ki Min; Eun Mi Nam

OBJECTIVE To evaluate the benefit of adjuvant radiotherapy (RT) after surgical resection for extrahepatic bile duct (EHBD) cancer. METHODS From 1997 to 2015, 59 patients with EHBD cancer were the subject of this study; 36 patients not undergoing adjuvant treatment after surgery (observation group) and 23 patients receiving adjuvant RT (RT group) were compared. Microscopic residual disease (R1) was in 9 (25%) patients and 5 (22%) patients, and macroscopic residual disease (R2) was in 2 (6%) patients and 6 (26%) patients in the observation and RT groups, respectively. Adjuvant RT was delivered to the tumour bed and regional lymph nodes up to 50.4 Gy (range, 45-61 Gy). RESULTS With a median follow-up of 19 months, local recurrence was observed in 10 (28%) patients and 2 (9%) patients in the observation and RT groups, respectively. On univariate analysis, the 5-year local recurrence-free survival (LRFS) rates were 50% in the observation group and 54% in the RT group (p = 0.401). The 5-year overall survival (OS) rates were 29.3% in the observation group and 26.3% in the RT group (p = 0.602). On multivariable analysis, however, adjuvant RT significantly improved LRFS [hazard ratio (HR), 0.310; 95% confidence interval (CI), 0.100-0.963; p = 0.043] and had a trend towards increased OS (HR, 0.491; 95% CI, 0.219-1.102; p = 0.085). Resection margin (RM) status was also correlated with LRFS (HR for R1 6.134, 95% CI 2.051-18.344; and HR for R2 18.551, 95% CI 3.680-93.520; p < 0.001) and OS (HR for R1 1.816, 95% CI 0.853-3.867; and HR for R2 3.564, 95% CI 1.175-10.809; p = 0.054). CONCLUSION RM status was a significant prognosticator of EHBD cancer, and adjuvant RT improved local control rate; thereby, survival rate might be increased. Advances in knowledge: The benefit of adjuvant RT in EHBD cancer was demonstrated via comparison with observation group.


British Journal of Radiology | 2017

Salvage radiotherapy for locoregionally recurrent extrahepatic bile duct cancer after radical surgery

Eunji Kim; Yi-Jun Kim; KimKyubo; Changhoon Song; Jae-Sung Kim; Do-Youn Oh; Eun Mi Nam; Eui Kyu Chie

OBJECTIVE This study evaluated the outcome of salvage radiotherapy for locoregionally recurrent extrahepatic bile duct cancer. METHODS We performed a retrospective review of 23 extrahepatic bile duct cancer patients who underwent radiotherapy with or without concomitant chemotherapy for isolated locoregional recurrence after radical surgery between August 2001 and September 2013. The median disease-free interval was 11.8 months. Salvage radiotherapy was delivered to the recurrent tumour with or without initial operation bed up to a median dose of 54 Gy (range, 45-60). 18 patients received concomitant chemotherapy. RESULTS The median follow-up period was 14.2 months for all patients, and 48.8 months for survivors. The median overall survival and progression-free survival (PFS) were 18.4 (range, 4.4-114.6) and 15.5 months (range, 1.6-114.6), respectively. On multivariate analysis, the use of concomitant chemotherapy was a favourable prognostic factor for PFS (p = 0.027), and prolonged disease-free interval (≥1 year) was associated with a significantly poor overall survival (p = 0.047). Grade 3 or higher toxicities did not occur in follow-up period. CONCLUSION Salvage radiotherapy showed promising survival outcomes in locoregional recurrence of extrahepatic bile duct cancer. Our results indicated that concomitant chemotherapy was associated with improved PFS. Concurrent chemoradiotherapy can be a viable salvage treatment option in selected patients. Advances in knowledge: Locoregional recurrence is the most common pattern of failure after radical resection in extrahepatic bile duct cancer. In this study, salvage radiotherapy showed favourable survival outcomes without severe complications in locoregionally recurrent extrahepatic bile duct cancer patients.


Radiation oncology journal | 2016

Treatment outcomes after adjuvant radiotherapy following surgery for patients with stage I endometrial cancer

Ji-Young Kim; Kyung-Ja Lee; Kyung-Ran Park; Boram Ha; Yi-Jun Kim; Wonguen Jung; Rena Lee; Seung Cheol Kim; Hye Sung Moon; Woong Ju; Yun Hwan Kim; Jihae Lee

Purpose The purpose of this study is to evaluate the treatment outcomes of adjuvant radiotherapy using vaginal brachytherapy (VB) with a lower dose per fraction and/or external beam radiotherapy (EBRT) following surgery for patients with stage I endometrial carcinoma. Materials and Methods The subjects were 43 patients with the International Federation of Gynecology and Obstetrics (FIGO) stage I endometrial cancer who underwent adjuvant radiotherapy following surgery between March 2000 and April 2014. Of these, 25 received postoperative VB alone, while 18 received postoperative EBRT to the whole pelvis; 3 of these were treated with EBRT plus VB. The median EBRT dose was 50.0 Gy (45.0–50.4 Gy) and the VB dose was 24 Gy in 6 fractions. Tumor dose was prescribed at a depth of 5 mm from the cylinder surface and delivered twice per week. Results The median follow-up period for all patients was 57 months (range, 9 to 188 months). Five-year disease-free survival (DFS) and overall survival (OS) for all patients were 92.5% and 95.3%, respectively. Adjuvant radiotherapy was performed according to risk factors and stage IB, grade 3 and lymphovascular invasion were observed more frequently in the EBRT group. Five-year DFS for EBRT and VB alone were 88.1% and 96.0%, respectively (p = 0.42), and 5-year OS for EBRT and VB alone were 94.4% and 96%, respectively (p = 0.38). There was no locoregional recurrence in any patient. Two patients who received EBRT and 1 patient who received VB alone developed distant metastatic disease. Two patients who received EBRT had severe complications, one each of grade 3 gastrointestinal complication and pelvic bone insufficiency fracture. Conclusion Adjuvant radiotherapy achieved high DFS and OS with acceptable toxicity in stage I endometrial cancer. VB (with a lower dose per fraction) may be a viable option for selected patients with early-stage endometrial cancer following surgery.


Anticancer Research | 2016

Two-year Follow-up of Volumetric-modulated Arc Therapy for Treating Internal Mammary Nodes in Locally Advanced Breast Cancer

Yi-Jun Kim; Kyubo Kim; Rena Lee; Ji-Young Kim; Wonguen Jung; Nam-Sun Paik; Byung-In Moon; Woosung Lim; Jihae Lee

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Kyubo Kim

Ewha Womans University

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Jihae Lee

Ewha Womans University

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Eun Mi Nam

Ewha Womans University

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Rena Lee

Ewha Womans University

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Do-Youn Oh

Seoul National University

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Eui Kyu Chie

Seoul National University

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