Publications by authors named "Leon Sun"

Introduction: Opioid use disorder (OUD) is a significant health issue impacting millions in the United States (US). Medications used for OUD (MOUD) (e.g.

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An unwelcoming policy climate can create barriers to health care access and produce a 'Chilling Effect' among immigrant communities. For undocumented immigrants, barriers may be unique and have a greater impact. We used administrative emergency department (ED) data from 2015 to 2019 for a Midwestern state provided under a data use agreement with the state hospital association.

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Article Synopsis
  • In 2016, the cancer registry community began directly assigning the components of cancer stage (T, N, M) due to frequent unavailability in medical records.
  • A field study involving 280 cases across various cancer types found that pathologic TNM data was more accessible than clinical data, with only about 20% of clinical elements available.
  • The study highlighted a significant need for improved training for registrars, as there was considerable variability in agreement between participant responses and assigned TNM data across different cancer types.
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Background: Several changes were made to bladder cancer staging guidelines between the 6th and 7th editions of the American Joint Committee on Cancer (AJCC) Staging Manual. Also, Collaborative Stage (CS) Data Collection System version 2 (CSv2) implemented for 2010 Surveillance, Epidemiology, and End Results (SEER) cases involved collection of 3 new site-specific factors (SSFs): World Health Organization/International Society of Urological pathology grade (SSF1), size of metastasis in regional lymph nodes (SSF2), and extranodal extension (SSF3). Our objective was to evaluate these new SSFs to assist researchers in their use/interpretation and to describe data quality issues to be addressed moving forward.

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Background: Version 2 of the Collaborative Stage Data Collection System (CSv2) became effective with cases diagnosed in 2010. This report focuses on the CSv2 components required to derive the American Joint Committee on Cancer (AJCC) stage for prostate cancer and on the site-specific factors for prostate cancer captured in CSv2. The report also highlights differences between the AJCC 6th and 7th editions for classifying prostate cancer stage.

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Prostate cancer is the most common cancer among men. The prospective discrimination of aggressive and clinically insignificant tumors still poses a significant and, as yet, unsolved problem. PITX2 DNA methylation is a strong prognostic biomarker in prostate cancer.

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To assess preoperative parameters that may be predictive of pathologic stage T2a (pT2a) and pathologic Gleason score (pGS) ≤ 6 disease in low-risk prostate cancer patients considering active surveillance. A cohort of 1,495 men with low-risk prostate cancer between 1993 and 2009 was utilized. Preoperative assessment focused on patient age, race, diagnostic PSA level, clinical stage, diagnostic biopsy Gleason score, and prostate cancer laterality.

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Objective: To assess preoperative parameters that may be predictive of pathologic stage T2a disease in low-risk prostate cancer patients.

Methods: Data from a cohort of 1,495 consecutive men with low-risk prostate cancer who underwent a radical prostatectomy between 1993 and 2009 were evaluated. Preoperative parameter assessment focused on age, race, clinical stage, diagnostic PSA level, biopsy tumor laterality and diagnostic Gleason score.

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To find the predictors of Gleason score upgrading in a cohort of low-risk prostate cancer patients, data were analyzed comprising 1,632 consecutive men with low-risk prostate cancer who underwent radical prostatectomy between 1993 and 2009. Assessment focused on preoperative parameters including patient age, race, diagnostic prostate-specific antigen (PSA) levels, clinical stage and biopsy Gleason score, along with pathological parameters including percentage of tumor involvement (PTI), tumor laterality, pathological stage, extra-capsular extension, seminal vesicle invasion, and surgical margins. These parameters were analyzed using univariate and multivariate methods.

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Background: Statistical prediction tools are increasingly common, but there is considerable disagreement about how they should be evaluated. Three tools--Partin tables, the European Society for Urological Oncology (ESUO) criteria, and the Gallina nomogram--have been proposed for the prediction of seminal vesicle invasion (SVI) in patients with clinically localized prostate cancer who are candidates for a radical prostatectomy.

Objectives: Using different statistical methods, we aimed to determine which of these tools should be used to predict SVI.

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There are 2 widely accepted methods for calculating data completeness in central cancer registries: The Surveillance, Epidemiology and End Results (SEER) Program's data completeness method and the North American Association of Central Cancer Registries' (NAACCR's) data completeness method. In recent years, the pros and cons of these methods have been discussed and debated by CTRs nationwide. The results from a myriad of studies have shown that each method offers its own set of strengths and unique applications.

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Purpose. Patients diagnosed with clinically localized prostate cancer have more surgical treatment options than in the past. This paper focuses on the procedures' oncological or functional outcomes and perioperative morbidities of radical retropubic prostatectomy, radical perineal prostatectomy, and robotic-assisted laparoscopic radical prostatectomy.

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Purpose: To evaluate the primary Gleason grade (GG) in Gleason score (GS) 7 prostate cancers for risk of non-organ-confined disease with the goal of optimizing radiotherapy treatment option counseling.

Methods: One thousand three hundred thirty-three patients with pathologic GS7 were identified in the Duke Prostate Center research database. Clinical factors including age, race, clinical stage, prostate-specific antigen at diagnosis, and pathologic stage were obtained.

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Objective: • To evaluate weather prostate-specific antigen (PSA) velocity could be used to stratify patients at risk of death from prostate cancer (PCa) and be useful in aiding decision making regarding PSA screening in elderly men, as previous studies have shown that PSA velocity can predict PCa risk.

Patients And Methods: • The cohort included 3,525 patients aged ≥ 75 years with two or more PSA tests before a diagnosis of PCa. Cox proportional hazard model was used to evaluate which variables at time of last PSA measurement were associated with death from PCa.

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Objectives: We previously showed that prostate-specific antigen (PSA) nadir after radical prostatectomy (RP) significantly predicts biochemical recurrence (BCR). Herein, we sought to explore the effect of including PSA nadir into commonly used models on their accuracy to predict BCR after RP.

Methods: This was a retrospective analysis of 943 and 1792 subjects from the Shared Equal Access Regional Cancer Hospital (SEARCH) and Duke Prostate Cancer (DPC) databases, respectively.

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Background: A diagnosis of prostate cancer is not often predictive of death from prostate cancer because of competing causes of mortality. Identification of the risk of death from prostate cancer and death from all causes using information available at the time of baseline prostate-specific antigen (PSA) measurement appears to be particularly pertinent.

Methods: The Duke Prostate Center database was used to identify men who had their PSA level measured over the past 20 years.

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Objective: To investigate whether salvage radiation therapy (RT) for prostate-specific antigen (PSA) failure can provide the same result as adjuvant RT, which decreases the risk of all-cause mortality (ACM) for men with positive margins (R1), or extra-capsular or seminal vesicle extension (pT3).

Methods: We studied 1638 men at Duke University who underwent radical prostatectomy for unfavourable-risk prostate cancer and whose postoperative PSA was undetectable. Cox regression was used to evaluate whether salvage vs adjuvant RT in men with a rapid (<10 months) or slow (≥10 months) PSA doubling time (DT) was associated with the risk of ACM, adjusting for adverse features (pT3, R1, Gleason score 8-10), age, preoperative PSA level, comorbidity and hormonal therapy use.

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Purpose: Radical prostatectomy is potentially curative in patients with clinically localized prostate cancer. However, biochemical recurrence affects 15% to 30% of men who undergo radical prostatectomy. We previously reported the prognostic potential of PITX2 gene promoter methylation using conventional assays.

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Objective: to analyse the relationship between African American (AA) race and obesity in men with prostate cancer.

Patients And Methods: in all, 4196 patients who underwent radical prostatectomy from 1988 to 2008 were identified in the Duke Prostate Center database. A subset of 389 (AA 20.

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Background: This report evaluated whether biochemical recurrence (BCR) as a time-dependent covariate (t) after radical prostatectomy (RP) for prostate cancer was associated with the risk of death and whether salvage therapy with radiotherapy (RT) and/or hormonal therapy (HT) can lessen this risk

Methods: This was a retrospective cohort study of 3071 men who underwent RP at Duke University between 1988 and 2008 and had complete follow-up data. A Cox regression multivariable analysis was used to determine whether BCR (t) was associated with the risk of death in men after adjusting for age, prostatectomy findings, and the use of salvage RT and/or HT.

Results: After a median follow-up of 7.

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Objective: To validate a model previously developed using the Shared Equal Access Regional Cancer Hospital (SEARCH) database to predict the risk of aggressive recurrence after surgery, defined as a prostate-specific antigen (PSA) doubling time (DT) of <9 months, incorporating pathological stage, preoperative PSA level and pathological Gleason sum, that had an area under the curve (AUC) of 0.79 using a cohort of men from the Duke Prostate Center (DPC).

Patients And Methods: Data were included from 1989 men from the DPC database who underwent RP for node-negative prostate cancer between 1987 and 2003.

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Purpose: We determined the predictive power of tumor percent involvement on prostate specific antigen recurrence in patients when stratified by prostate weight.

Materials And Methods: Data on 3,057 patients who underwent radical prostatectomy between 1988 and 2008 was retrieved from our institutional prostate cancer database. Patients with data on tumor percent involvement, prostate volume and prostate specific antigen recurrence were included in analysis.

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Purpose: Studies show that initial prostate specific antigen higher than the median in young men predicts a subsequent higher risk of prostate cancer. To our knowledge this relationship has not been studied in patients stratified by race.

Materials And Methods: A cohort of 3,530 black and 6,118 white men 50 years or younger with prostate specific antigen 4 ng/ml or less at the first prostate specific antigen screening was retrieved from the prostate center database at our institution.

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Objective: To evaluate the association between prostate weight and the diagnostic performance of routine biopsy schemes in detecting unilateral prostate cancer (PCa) that may be amenable to focal therapy.

Methods And Materials: Retrospective analysis of patients undergoing radical prostatectomy at Duke University Medical Center from 1990 to 2007. The cohort was dichotomized according to prostate weight (≤40 and >40 g) and further divided by biopsy scheme: 6-9 (sextant) and 10-20 cores (extended).

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