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Featured researches published by David Y. Yang.


Urology | 2016

Quality of Life Assessment in Spina Bifida for Children (QUALAS-C): Development and Validation of a Novel Health-related Quality of Life Instrument.

Konrad M. Szymanski; Rosalia Misseri; Benjamin Whittam; David Y. Yang; Sonia Maria Raposo; Shelly J. King; Martin Kaefer; Richard C. Rink; Mark P. Cain

OBJECTIVE To develop and validate a self-reported health-related QUAlity of Life Assessment in Spina bifida for Children (QUALAS-C). METHODS We drafted a 27-question pilot instrument using a patient-centered comprehensive item generation and refinement process. It was administered to a sample of children 8-12 years old with spina bifida (SB) recruited online via social media and in person at an outpatient SB clinic (January 2013-September 2014). Healthy controls were recruited at routine pediatrician visits. Validation and final questions were determined based on clinical relevance, high loadings on factor analysis, and domain psychometrics. Children with SB also completed the validated generic Kidscreen-27 instrument. RESULTS Median age of 150 participants was 9.6 years (60.7% male, 72.7% Caucasian), similar to 46 controls (P ≥ .10). There were 97 online and 53 clinic participants (89.0% and 84.2% of eligible, respectively). Face and content validities of the 2-domain, 10-question QUALAS-C were established by patients, parents, and experts. Internal consistency and test-retest reliability was high for the Esteem & Independence and Bladder & Bowel domains (Cronbachs alpha: 0.72-0.76, ICC: 0.74-0.77). Correlations between QUALAS-C domains were low (r = 0.51), indicating that QUALAS-C can differentiate between two distinct health-related quality of life components. Correlations between QUALAS-C and Kidscreen-27 were also low (r ≤ 0.44). QUALAS-C scores were significantly lower in children with SB than without (P < .0001). CONCLUSION QUALAS-C is a short, valid health-related quality of life tool for children with SB. It will be useful in clinical and research settings.


Urologic Oncology-seminars and Original Investigations | 2015

Oncologic and quality-of-life outcomes with wide resection in robot-assisted laparoscopic radical prostatectomy

David Y. Yang; M. Francesca Monn; Hristos Z. Kaimakliotis; K. Clint Cary; Liang Cheng; Michael O. Koch

OBJECTIVES To assess urinary quality-of-life (QoL) and oncologic outcomes between wide resection (WR) robot-assisted laparoscopic radical prostatectomy (RALP) and non-WR (NWR) RALP in men with intermediate- or high-risk (Cancer of the Prostate Risk Assessment [CAPRA]-9 >2) prostate adenocarcinoma. METHODS Patients undergoing RALP (2004-2013) for intermediate- or high-risk prostate adenocarcinoma were analyzed. Kaplan-Meier methodology with Cox proportional hazards regression evaluated biochemical recurrence-free survival (BCR-FS). Multiple logistic regression was used to determine the relationship between (1) WR with positive surgical margins (+SM) and (2) WR with posterolateral+SM after adjusting for demographics and CAPRA-9 score. University of California, Los Angeles-Prostate Cancer Index and Extended Prostate Cancer Index Composite questionnaires assessed urinary QoL. Multiple mixed-effects linear regression adjusting for demographics and CAPRA-9 evaluated differences in QoL between WR and NWR. RESULTS A total of 483 RALP cases met inclusion criteria-129 (26.7%) underwent WR and 354 (73.3%) underwent NWR-RALP. There were no demographic differences between groups. Burden of disease was greater in patients undergoing WR (P<0.001). There was no difference in+SM rates between WR and NWR (P = 0.505). Adjusting for demographics and CAPRA-9 score, WR patients had a clinically relevant 27% decrease in posterolateral+SM (odds ratio = 0.73; 95% CI: 0.38-1.41; P = 0.351). WR was not associated with worse BCR-FS (hazard ratio = 1.24; 95% CI: 0.83-1.86, P = 0.30). Adjusting for pathology, University of California, Los Angeles and Extended Prostate Cancer Index Composite urinary domain scores were similar between WR and NWR groups. CONCLUSION Despite WR patients having worse clinical disease, WR-RALP can be performed with minimal detriment to BCR-FS and urinary QoL. The greater incidence of occult metastasis in higher risk patients may make surgical technique a nonsignificant factor. Nevertheless, WR remains a reasonable option for complete surgical excision.


Urology Practice | 2015

Does Squamous Differentiation Portend Worse Outcomes in Urothelial Bladder Cancer

David Y. Yang; M. Francesca Monn; Hristos Z. Kaimakliotis; Jane S. Cho; K. Clint Cary; Jose A. Pedrosa; Richard Bihrle; Liang Cheng; Michael O. Koch

Introduction: Interest on the impact of variant histology in bladder cancer prognosis is increasing. Although squamous differentiation is the most well characterized, only recently have less common variants gained increased recognition. We assessed whether squamous differentiation conferred a worse prognosis than nonvariant urothelial bladder cancer in a contemporary cohort of patients treated with radical cystectomy given the increased awareness of other less common variants. Methods: We identified patients with squamous differentiation or nonvariant histology on transurethral resection of bladder tumor and/or cystectomy pathology during a 10‐year period. Disease specific and overall survival were evaluated using Kaplan‐Meier methodology. Cox regression was used to assess variables associated with mortality. Results: Between 2003 and 2013, 934 patients underwent cystectomy for urothelial bladder cancer. Overall 617 nonvariant and 118 squamous differentiation cases were identified, and the remainder was nonsquamous differentiation variant histology. Overall 75% of patients with squamous differentiation had muscle invasive disease at diagnosis compared with 59% of those with nonvariant histology (p=0.002). Nonorgan confined disease at cystectomy was more common in patients with squamous differentiation (57% vs 44%, p=0.009). Among cases on neoadjuvant chemotherapy 20% (9 of 45) of nonvariant and 13% (1 of 8) of squamous differentiation were pT0N0 (p=0.527). Median followup was 52 months. Adjusted for demographics, pathological stage and chemotherapy, squamous differentiation was not associated with an increased risk of disease specific (HR 1.35, 95% CI 0.90–2.04, p=0.150) or all cause mortality (HR 0.90, 95% CI 0.60–1.25, p=0.515). Conclusions: In a contemporary cohort of urothelial bladder cancer with recognition and characterization of less commonly described variants, squamous differentiation is not associated with a worse disease specific and all cause mortality when compared to a pure nonvariant cohort.


The Journal of Urology | 2014

Does Robotic Assistance Confer an Economic Benefit during Laparoscopic Radical Nephrectomy

David Y. Yang; M. Francesca Monn; Clinton D. Bahler; Chandru P. Sundaram


The Journal of Urology | 2014

V5-01 ROBOT ASSISTED LAPAROSCOPIC RETROPERITONEAL PARTIAL NEPHRECTOMY FOR A POSTERIOR HILAR TUMOR AND A POSTERIOR HORSESHOE KIDNEY TUMOR

David Y. Yang; Clinton D. Bahler; Chandru P. Sundaram


PMC | 2017

Validation of QUALAS-T, a health-related quality of life instrument for teenagers with spina bifida

Konrad M. Szymanski; Rosalia Misseri; Benjamin Whittam; Jessica T. Casey; David Y. Yang; Sonia-Maria Raposo; Shelly J. King; Martin Kaefer; Richard C. Rink; Mark P. Cain


Author | 2016

Quality of Life Assessment in Spina Bifida for Children (QUALAS-C): Development and Validation of a Novel Health-related Quality of Life Instrument

Konrad M. Szymanski; Rosalia Misseri; Benjamin Whittam; David Y. Yang; Sonia-Maria Raposo; Shelly J. King; Martin Kaefer; Richard C. Rink; Mark P. Cain


The Journal of Urology | 2015

PD3-09 PHEOCHROMOCYTOMA: A COMPARISON OF PERIOPERATIVE MANAGEMENT WITH CALCIUM CHANNEL BLOCKERS AND SELECTIVE AND NON-SELECTIVE ALPHA RECEPTOR BLOCKERS

Ryan W. Zipper; Clinton D. Bahler; M. Francesca Monn; David Y. Yang; Matthew J. Mellon; Chandru P. Sundaram


The Journal of Urology | 2015

V8-05 CONCOMITANT HOLMIUM LASER ENUCLEATION OF THE PROSTATE (HOLEP) AND LAPAROSCOPIC ROBOT-ASSISTED BLADDER DIVERTICULECTOMY FOR TREATMENT OF A LARGE BLADDER TUMOR

Adam C. Calaway; David Y. Yang; Jessica E. Paonessa; James E. Lingeman; Ronald S. Boris


The Journal of Urology | 2015

PD21-04 MATCHED COMPARISON OF PRIMARY VERSUS SALVAGE LAPAROSCOPIC PYELOPLASTY (LP)

Sapan N. Ambani; David Y. Yang; J. Stuart Wolf

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