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Dive into the research topics where Sangjun Yoo is active.

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Featured researches published by Sangjun Yoo.


Korean Journal of Urology | 2011

Predictive Characteristics of Malignant Pheochromocytoma

Junsoo Park; Cheryn Song; Myungchan Park; Sangjun Yoo; Sejun Park; Seokjun Hong; Bumsik Hong; Choung-Soo Kim; Hanjong Ahn

Purpose The prognosis of patients with malignant pheochromocytoma is poor, but the predictive factors are not well understood. We aimed to identify the clinical characteristics predictive of malignancy after initial surgical removal in patients with pheochromocytoma. Materials and Methods We retrospectively reviewed the records of 152 patients diagnosed with pheochromocytoma, including 5 (3.3%) with metastasis at the time of the initial surgical excision and 12 (7.9%) who developed metastasis during follow-up. To determine the factors predictive of malignancy, we compared clinical, radiographical, and urinary chemical findings between patients with benign and malignant disease. Mean follow-up was 41.5 months (range, 0.9-298 months) after surgery. Results Malignant tumors were significantly larger than benign tumors (11.1±4.0 cm vs. 6.2±3.4 cm, p<0.001), and postoperative persistence of arterial hypertension was more frequent after removal of malignant than benign tumors (p=0.001). Among the 147 patients without metastatic disease at diagnosis, those who developed metastasis had significantly lower concentrations of urinary catecholamine metabolites per unit of tumor, including vanillylmandelic acid (1.2 vs. 3.7 mg/day/cm, p=0.049), epinephrine (4.5 vs. 168.9 µg/day/cm, p=0.008), and norepinephrine (13.1 vs. 121.8 mg/day/cm, p<0.001). The overall 5-year metastasis-free survival rate was 84.4% and was significantly higher in patients with smaller tumors (≤5.5 vs. >5.5 cm; 90.6% vs. 81.2%, p=0.025) and higher 24-hour secretion of vanillylmandelic acid (>2.1 vs. ≤2.1 mg/day/cm; 94.9% vs. 70.9%, p=0.019). Conclusions Large tumor size (>5.5 cm) and minimally elevated 24-hour urinary vanillylmandelic acid (≤2.1 mg/day/cm) were significantly associated with a higher probability of a malignant pheochromocytoma portending a lower metastasis-free survival and mandating more rigorous follow-up after surgery.


Korean Journal of Urology | 2015

Multiparametric magnetic resonance imaging for prostate cancer: A review and update for urologists

Sangjun Yoo; Jeong Kon Kim; In Gab Jeong

Recently, imaging of prostate cancer has greatly advanced since the introduction of multiparametric magnetic resonance imaging (mpMRI). mpMRI consists of T2-weighted sequences combined with several functional sequences including diffusion-weighted imaging, dynamic contrast-enhanced imaging, and/or magnetic resonance spectroscopy imaging. Interest has been growing in mpMRI because no single MRI sequence adequately detects and characterizes prostate cancer. During the last decade, the role of mpMRI has been expanded in prostate cancer detection, staging, and targeting or guiding prostate biopsy. Recently, mpMRI has been used to assess prostate cancer aggressiveness and to identify anteriorly located tumors before and during active surveillance. Moreover, recent studies have reported that mpMRI is a reliable imaging modality for detecting local recurrence after radical prostatectomy or external beam radiation therapy. In this regard, some urologic clinical practice guidelines recommended the use of mpMRI in the diagnosis and management of prostate cancer. Because mpMRI is the evolving reference standard imaging modality for prostate cancer, urologists should acquire cutting-edge knowledge about mpMRI. In this article, we review the literature on the use of mpMRI in urologic practice and provide a brief description of techniques. More specifically, we state the role of mpMRI in prostate biopsy, active surveillance, high-risk prostate cancer, and detection of recurrence after radical prostatectomy.


Urologic Oncology-seminars and Original Investigations | 2013

Tumor volume, surgical margin, and the risk of biochemical recurrence in men with organ-confined prostate cancer

Cheryn Song; Taejin Kang; Sangjun Yoo; In Gab Jeong; Jae Y. Ro; Jun Hyuk Hong; Choung Soo Kim; Hanjong Ahn

OBJECTIVES We proposed to investigate predictors of biochemical recurrence (BCR) in pT2 prostate cancer by identifying the interrelationship between the tumor volume and surgical margin status, and their impact on recurrence. MATERIALS AND METHODS Clinical, pathologic, and follow-up data of 404 consecutive patients who were treated with radical prostatectomy alone and were diagnosed as pT2 prostate cancer in our institution were reviewed. Percent tumor volume (PTV) was estimated from the cancer distribution map, and the surgical margin status was reviewed by a single pathologist (JYR). Clinicopathologic variables were analyzed with respect to the risk of BCR. RESULTS AND LIMITATIONS Recurrence was observed in 39 (9.7%) patients at a mean of 28.9 (5-47) months. Preoperative PSA, biopsy Gleason score, surgical Gleason score, PTV, and surgical margin status were significantly related to BCR in univariate analysis; in multivariate analysis, PTV (P < 0.001) and surgical Gleason score (P = 0.021) were independent predictors of BCR. PTV was also an independent determinant of positive surgical margin (P = 0.035, HR 1.026, 95% CI 1.002-1.050). By combining the 2 predictors 5-year recurrence-free survivals for PTV ≤ 14.5% and surgical Gleason score ≤ 7, PTV >14.5% or surgical Gleason score > 7, and PTV > 14.5% and surgical Gleason score > 7 were 97.5%, 88.7%, and 44.5%, respectively (log-rank test, P < 0.01). Retrospective study nature, use of PTV instead of actual volume, and intermediate follow-up length are the main limitations of the study. CONCLUSIONS In men with pT2 prostate cancer, percent tumor volume and the surgical Gleason score were independently prognostic of BCR and by combining the 2 factors, risk of BCR could be significantly stratified. Tumor volume further determined surgical margin status undermining its prognostic value as an independent variable.


Oncotarget | 2017

Comparison of outcomes between trimodal therapy and radical cystectomy in muscle-invasive bladder cancer: a propensity score matching analysis

Yeon Joo Kim; Sang Jun Byun; Hanjong Ahn; Choung-Soo Kim; Beom-Sik Hong; Sangjun Yoo; Young Seok Kim

Although radical cystectomy (RC) is considered as the standard therapy for muscle-invasive bladder cancer (MIBC), trimodal therapy (TMT) combining transurethral resection of the tumor with radiotherapy and chemotherapy is increasingly recommended as an alternative approach for bladder preservation. In the absence of randomized trials, we compared the clinical outcomes between RC and TMT using propensity score matching with 50 patients in the RC arm and 29 patients in the TMT arm. With respective median follow-up periods of 23 and 32 months for the RC and TMT groups, 5-year distant metastasis-free survival (58% vs. 67%), overall survival (56% vs. 57%), and cancer-specific survival (69% vs. 63%) rates between the RC and TMT groups, respectively, were similar. However, the 5-year local recurrence-free survival was significantly better in the RC group than in the TMT group (74% vs. 35%). Following TMT, acute grade 3 hematological (n = 2) and late grade 3 genitourinary (n = 1) toxicities were reported. These findings demonstrated that oncological outcomes of TMT were comparable with those of RC, except for poorer local control. Large-scale, randomized trials are warranted to confirm the findings of the present retrospective comparison and to guide toward best treatment options.Although radical cystectomy (RC) is considered as the standard therapy for muscle-invasive bladder cancer (MIBC), trimodal therapy (TMT) combining transurethral resection of the tumor with radiotherapy and chemotherapy is increasingly recommended as an alternative approach for bladder preservation. In the absence of randomized trials, we compared the clinical outcomes between RC and TMT using propensity score matching with 50 patients in the RC arm and 29 patients in the TMT arm. With respective median follow-up periods of 23 and 32 months for the RC and TMT groups, 5-year distant metastasis-free survival (58% vs. 67%), overall survival (56% vs. 57%), and cancer-specific survival (69% vs. 63%) rates between the RC and TMT groups, respectively, were similar. However, the 5-year local recurrence-free survival was significantly better in the RC group than in the TMT group (74% vs. 35%). Following TMT, acute grade 3 hematological (n = 2) and late grade 3 genitourinary (n = 1) toxicities were reported. These findings demonstrated that oncological outcomes of TMT were comparable with those of RC, except for poorer local control. Large-scale, randomized trials are warranted to confirm the findings of the present retrospective comparison and to guide toward best treatment options.


Clinical Genitourinary Cancer | 2017

Prognostic Factors for Survival of Patients With Synchronous or Metachronous Brain Metastasis of Renal Cell Carcinoma

Se Young Choi; Sangjun Yoo; Dalsan You; In Gab Jeong; Cheryn Song; Bumsik Hong; Jun Hyuk Hong; Hanjong Ahn; Choung-Soo Kim

Micro‐Abstract We evaluated the oncological outcomes of synchronous or metachronous brain metastasis (BM) of metastatic renal cell carcinoma. Although the type of BM, synchronous or metachronous, does not influence BM progression or the overall survival outcome, poor MSKCC risk, sarcomatoid component of histology, and multiple BMs are prognostic indicators for poor overall survival. Routine evaluation for BM is not recommended. Introduction: We evaluated the oncological outcomes of synchronous or metachronous brain metastasis (BM) of metastatic renal cell carcinoma (RCC) according to clinicopathologic factors. Patients and Methods: Patients with metastatic RCC (n = 93) with synchronous and metachronous BM were retrospectively identified. We analyzed patients and tumor characteristics, treatment methods, prognostic factors, BM progression, and overall survival (OS). Results: Seventy‐six patients (81.7%) received local therapy (stereotactic radiosurgery [60.2%], radiation therapy [22.6%], and neurosurgery [10.8%]), and 54 patients (58.1%) were treated with systemic medical therapy. In multivariable analysis, poor Memorial Sloan‐Kettering Cancer Center (MSKCC) risk (hazard ratio [HR] 3.672; 95% confidence interval [CI], 1.441‐9.36; P = .0064), sarcomatoid component (HR 4.264; 95% CI, 2.062‐8.820; P = .0001), and multiple BMs (HR 2.838; 95% CI, 1.690‐4.767; P = .0001) were prognostic indicators of a poorer OS outcome. Local (HR 0.436; 95% CI, 0.237‐0.802; P = .0076) and systemic treatment (HR 0.322; 95% CI, 0.190‐0.548; P < .0001) were independent factors for a better OS. Although OS from initial RCC diagnosis in patients with metachronous BM was better than that for patients with synchronous BM, there were no differences found between synchronous and metachronous patients in terms of BM progression and OS after the diagnosis of BM. Conclusions: Poor MSKCC risk, sarcomatoid component of histology, and multiple BMs are prognostic indicators for poor OS in patients with BM from metastatic RCC. Systemic and/or local treatment improves the OS. Because the type of BM, synchronous or metachronous, does not influence BM progression or the OS outcome, routine evaluation for BM is not recommended.


Journal of Korean Medical Science | 2017

Preserving Renal Function through Partial Nephrectomy Depends on Tumor Complexity in T1b Renal Tumors

Sangjun Yoo; Dalsan You; In Gab Jeong; Bumsik Hong; Jun Hyuk Hong; Choung-Soo Kim; Hanjong Ahn; Cheryn Song

This study aimed to determine patients with T1b renal cell carcinoma (RCC) who could benefit from partial nephrectomy (PN) and method to identify them preoperatively using nephrometry score (NS). From a total of 483 radical nephrectomy (RN)-treated patients and 40 PN-treated patients who received treatment for T1b RCC between 1995 and 2010, 120 patients identified through 1:2 propensity-score matching were included for analysis. Probability of chronic kidney disease (CKD) until postoperative 5-years was calculated and regressed with respect to the surgical method and NS. Median follow-up was 106 months. CKD-probability at 5-years was 40.7% and 13.5% after radical and PN, respectively (P = 0.005). While PN was associated with lower risk of CKD regardless of age, comorbidity, preoperative estimated renal function, the effect was observed only among patients with NS ≤ 8 (P < 0.001) but not in patients with NS ≥ 9 (P = 0.746). Percent operated-kidney volume reduction and ischemia time were similar between the patients with NS ≥ 9 and ≤ 8. In the stratified Cox regression accounting for the interaction observed between the surgical method and the NS, PN reduced CKD-risk only in patients with NS ≤ 8 (hazard ratio [HR], 0.054; P = 0.005) but not in ≥ 9 (HR, 0.996; P = 0.994). In T1b RCC with NS ≥ 9, the risk of postoperative CKD was not reduced following PN compared to RN. Considering the potential complications of PN, minimally invasive RN could be considered with priority in this subgroup of patients.


Korean Journal of Urology | 2011

Does radical cystectomy improve overall survival in octogenarians with muscle-invasive bladder cancer?

Sangjun Yoo; Dalsan You; In Gab Jeong; Jun Hyuk Hong; Hanjong Ahn; Choung Soo Kim

Purpose We compared the efficacy of radical cystectomy (RC) and non-RC treatment [transurethral resection of bladder tumor (TURB) only, partial cystectomy, or TURB followed by radiotherapy] in octogenarians with muscle-invasive bladder cancer (MIBC). Materials and Methods A total of 177 patients aged 80 years or more underwent TURB at our institute, and 41 patients had MIBC according to the histologic examination. Fourteen patients with lymph node or distant metastasis were excluded, and 27 patients were ultimately included. Patients were stratified by treatment modality (RC vs. non-RC), Charlson Comorbidity Index (low CCI vs. high CCI), and clinical tumor stage (organ-confined disease vs. extravesical disease). The effects of several variables on cancer-specific and overall survival were assessed. Results Of the 27 patients, 11 (41%) underwent RC and 16 (59%) underwent non-RC treatment. Patients in the RC group were younger and more likely to have low CCI scores. There were no significant differences in overall or cancer-specific survival in the RC and non-RC groups. Patients with clinically organ-confined disease had better survival outcomes than did those with extravesical disease. Stratification of patients by CCI indicated that overall survival was better in patients with low CCI scores (p=0.013), although cancer-specific survival was similar in the two CCI groups. Univariate and multivariate analysis indicated that clinical tumor stage and CCI were independently associated with overall survival. Conclusions RC in octogenarians with MIBC does not improve overall survival compared with other treatment modalities. However, clinically organ-confined disease and low CCI score were associated with better overall survival.


Urologic Oncology-seminars and Original Investigations | 2017

Lymph node density vs. the American Joint Committee on Cancer TNM nodal staging system in node-positive bladder cancer in patients undergoing extended or super-extended pelvic lymphadenectomy

D. H. Lee; Sangjun Yoo; Dalsan You; Bumsik Hong; Yong Mee Cho; Jun Hyuk Hong; Choung Soo Kim; Hanjonh Ahn; Jae Y. Ro; In Gab Jeong

PURPOSE We compared the prognostic value of the American Joint Committee on Cancer (AJCC) TNM nodal staging system with that of lymph node (LN) density in patients with LN-positive bladder cancer who received extended or super-extended pelvic lymphadenectomy. METHODS Of the 1,018 patients, who underwent radical cystectomy and pelvic lymphadenectomy between February 2005 and August 2014, 110 patients with LN metastases with extended (n = 68) or super-extended (n = 42) pelvic lymphadenectomy were included. All patients were staged using the 2002 (sixth edition) and 2010 (seventh edition) AJCC TNM staging systems. The association of several variables with recurrence-free survival (RFS) and overall survival (OS) was evaluated. RESULTS The median number of total LNs removed was 29 (6-118) and the median LN density was 12.5% (1.6%-100%). RFS and OS were not significantly different between the 2002 (pN1-pM1) and 2010 (pN1-N3) AJCC TNM nodal staging systems (sixth edition: P = 0.512 and P = 0.519; seventh edition: P = 0.676 and P = 0.671, respectively). The 2-year RFS and OS rates according to the LN density quartiles were 58.5% and 76.9% in Q1, 39.1% and 70.8% in Q2, 28.8% and 50.1% in Q3, and 12.7% and 20.8% in Q4 (P = 0.001 and P = 0.001, respectively). Multivariate analysis adjusted for the 2010 AJCC TNM staging system showed that LN density was associated with a decreased OS (HR = 1.024; 95% CI: 1.010-1.039; P = 0.001). The nodal staging system (2002 or 2010) was not associated with the RFS and OS. CONCLUSIONS LN density shows a better prognostic value than the AJCC TNM nodal staging system in patients with LN-positive bladder cancer receiving extended or super-extended pelvic lymphadenectomy.


Urologic Oncology-seminars and Original Investigations | 2018

Declining incidence of benign lesions among small renal masses treated with surgery: Effect of diagnostic tests for characterization

Sangjun Yoo; Dalsan You; Cheryn Song; Bumsik Hong; Jun Hyuk Hong; Choung-Soo Kim; Hanjong Ahn; In Gab Jeong

PURPOSE We evaluated the changes in the incidence of benign lesions in surgically removed small renal masses (SRMs) and the effect of diagnostic tests for characterizing SRMs. METHODS We included 2,707 patients receiving surgery for SRMs (<4cm). Trends in the incidence of benign histology were evaluated according to the surgery year (period 1: 2001-2005, 2: 2006-2010, and 3: 2011-2015). Multivariable logistic regression analysis was performed to identify factors associated with benign lesions. Additionally, the number of surgeries prevented due to benign histological findings on renal mass biopsies (RMB) done on 206 patients with SRM during study period was evaluated. RESULTS Benign histology was identified in 192 (7.1%) patients. Incidence of benign histology was 9.7%, 7.0%, and 6.3% for period 1, 2 and 3, respectively. The uses of multiphase computed tomography and magnetic resonance imaging were more common in periods 2 and 3 than in period 1 (P<0.001). The use of RMB in period 3 was higher than in periods 1 and 2 (0.8 vs. 0.9 vs. 9.0%, P<0.001). In multivariable analysis, older age, male sex, larger tumor size, and recent surgery year (period 3 vs. 1, odds ratio = 0.62, P = 0.028) were independently associated with decreased odds of benign lesions. The number of prevented surgeries by performing RMB was 0, 10, and 39 in periods 1, 2, and 3, respectively. CONCLUSIONS Incidence of benign histology after surgery for SRMs declined during recent years, which might be associated with the recent increased use of RMB.


Urologia Internationalis | 2017

Combination of Androgen Deprivation Therapy and Salvage Radiotherapy versus Salvage Radiotherapy Alone for Recurrent Prostate Cancer after Radical Prostatectomy

Sangjun Yoo; Dalsan You; Young Seok Kim; Jun Hyuk Hong; Hanjong Ahn; Choung-Soo Kim

Introduction: To assess the value of androgen deprivation therapy (ADT) on salvage radiotherapy (RT) in post-prostatectomy recurrent prostate cancer patients, we compared the oncologic outcomes between patients receiving RT + ADT and those receiving RT alone. Materials and Methods: We reviewed the records of patients diagnosed with prostate cancer between 1995 and 2011, including 93 patients who underwent salvage RT and 69 patients who underwent salvage RT + ADT. The ADT-free duration after withdrawal was calculated to verify testosterone recovery. Results: Presalvage prostate serum antigen (PSA) was the only significantly different characteristic between the 2 groups (p < 0.001). The ADT-free duration was greater than 6 months in >80% of patients. Presalvage PSA ≥0.6 ng/mL, pathologic stage ≥T3b, and RT + ADT were significantly associated with biochemical progression after salvage treatment. RT + ADT reduced biochemical progression in patients with seminal vesicle invasion or presalvage PSA ≥0.6 ng/mL (p = 0.001) compared to RT alone; biochemical progression-free probability was unchanged in seminal vesicle noninvasive prostate cancer patients with presalvage PSA <0.6 ng/mL (p = 0.541). Conclusions: RT + ADT reduced the risk of biochemical progression after salvage treatment in patients with seminal vesicle invasion or presalvage PSA ≥0.6 ng/mL, but had no effect in patients with seminal vesicle noninvasive disease and presalvage PSA <0.6 ng/mL.

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Juhyun Park

Seoul National University

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Min Chul Cho

Seoul National University

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