Timothy N. Clinton
University of Texas Southwestern Medical Center
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Featured researches published by Timothy N. Clinton.
Urologic Oncology-seminars and Original Investigations | 2018
Solomon L. Woldu; Justin T. Matulay; Timothy N. Clinton; Nirmish Singla; Laura Maria Krabbe; Ryan Hutchinson; Arthur I. Sagalowsky; Yair Lotan; Vitaly Margulis; Aditya Bagrodia
BACKGROUND Given the rarity of testicular germ cell tumors (TGCTs) and the complex aspects of management, we evaluate the effect of hospital TGCT case volume on overall survival outcomes and practice patterns. MATERIALS AND METHODS The National Cancer Database was queried for patients diagnosed with seminoma or nonseminomatous germ cell tumor (NSGCT). Hospitals were classified by case volume as high (99th percentile, ≥26.1 cases annually), high-intermediate (95-99th percentile, 14.6-26.0 cases annually), intermediate (75-95th percentile, 6.1-14.5 cases annually), low-intermediate (25-75th percentile, 1.8-6.0 cases annually), and low (25th percentile,<1.8 cases annually). The median (interquartile range) number of TGCT cases per institution per year was 3.4 (1.8-6.1). RESULTS A total of 33,417 patients with TGCT diagnosed from 1,239 institutions met inclusion criteria. Despite worse disease characteristics of patients treated at higher volume institutions, hospital volume was positively associated with survival outcomes in more advanced cases of TGCT. In the overall cohort, compared to the high-volume hospitals, patients treated at high-intermediate, intermediate, low-intermediate, and low volume hospitals the hazard ratio for overall mortality was 1.28, 1.45, 1.48, and 1.83, respectively (P<0.05). The association between survival and hospital volume was not apparent for seminoma or stage I NSGCT. Patients treated at higher volume hospitals were more likely to undergo surveillance for stage I seminoma, primary retroperitoneal lymph node dissection (RPLND) for stage I NSGCT, and postchemotherapy RPLND for stage II/III NSGCT. CONCLUSIONS Our analysis of a nationwide cancer registry demonstrated that increased hospital TGCT case volume was associated with significant differences in management strategies and improved survival outcomes, in particular for more advanced disease.
Expert Opinion on Pharmacotherapy | 2017
Timothy N. Clinton; Solomon L. Woldu; Ganesh V. Raj
ABSTRACT Introduction: Androgen deprivation therapy (ADT) is the mainstay for advanced, hormone-sensitive prostate cancer, and options include surgical castration, luteinizing hormone-releasing hormone (LHRH) agonist, and more recently, gonadotropin releasing hormone (GnRH) antagonist therapy. Our understanding of the mechanisms and adverse effects of ADT has increased substantially, including the class-specific adverse effects of ADT. Areas covered: This review will summarize the pharmacodynamic and pharmacokinetic properties of the GnRH antagonist degarelix and its role in the management of advanced prostate cancer, the clinical evidence supporting its regulatory approval, as well as potential benefits and disadvantages over traditional LHRH agonist therapy. Expert opinion: Degarelix represents a newer class of ADT that results in a rapid and reliable decline in serum testosterone, a quality that makes it particularly advantageous in men presenting with symptomatic, hormone-sensitive prostate cancer. Due to differences in mechanism of action, there is observational data suggesting a potential cardiovascular and even oncologic benefit over traditional LHRH agonist therapy. Further research is ongoing to more clearly define this potential benefit.
Urology | 2017
Solomon L. Woldu; Ahmet Aydin; Ashwin V. Rao; Ryan Hutchinson; Nirmish Singla; Timothy N. Clinton; Laura Maria Krabbe; Niccolò Passoni; Ganesh V. Raj; David Miller; James F. Amatruda; Arthur I. Sagalowsky; Yair Lotan; Yull Edwin Arriaga; Vitaly Margulis; Aditya Bagrodia
OBJECTIVE To describe epidemiologic patterns, stage at presentation, histology, and treatment differences associated with Hispanic men diagnosed with testicular germ cell tumor (TGCT). Hispanics are the fastest growing demographic in the United States and reports suggest that the incidence of TGCT is rising most rapidly in this demographic, yet little is known about TGCTs in Hispanic patients. MATERIALS AND METHODS We compared patient factors, tumor characteristics, treatment patterns, and outcomes of non-Hispanic white (NHW) vs Hispanic patients at our own institution in North Texas from 2010 to 2016. The findings were corroborated by analyzing the National Cancer Database testicular cancer registry from 2004 to 2014. RESULTS We identified 154 patients with TGCT at our institution, of which 89 were NHW (56.0%) and 65 were Hispanic (40.9%). A review of the National Cancer Database identified 49,607 NHW patients (81.5%) and 6724 Hispanic patients (11.0%) diagnosed with TGCT. At presentation, Hispanic patients were approximately 5 years younger than NHW patients, delay seeking care for testicular cancer, were more likely to have nonseminomatous histology, had a larger tumor size, and had a higher disease burden at presentation. Additionally, we identified differences in treatment patterns at the national level. CONCLUSION Differences in outcomes and treatment patterns of Hispanic and NHW patients with TGCT may represent underlying socioeconomic issues and access to care; however, discrepancies in age of onset and histology of TGCT between Hispanic and NHW patients may signify differences in tumor biology or risk factors. We suggest that this possibility be explored further as we embark upon the genomic classification of TGCT.
Urologic Oncology-seminars and Original Investigations | 2017
Solomon L. Woldu; Bo Ci; Ryan Hutchinson; Laura Maria Krabbe; Nirmish Singla; Niccolò Passoni; Timothy N. Clinton; Ganesh V. Raj; David Miller; Arthur I. Sagalowsky; Yair Lotan; Yang Xie; Vitaly Margulis; Aditya Bagrodia
OBJECTIVES To evaluate the usage of surgical staging of inguinal lymph nodes (SSILNs) in the United States for intermediate to high-risk, clinically localized penile squamous cell cancer (SCC), to explore patient and hospital factors associated with omission of this staging, and to evaluate the effect on survival. PATIENTS AND METHODS Retrospective, observational study using the National Cancer Database from 2004 to 2014 of 1,689 men diagnosed with pT1b-T3, cN0 penile SCC, who by current guidelines should receive SSILNs-either by inguinal lymph node (ILN) dissection or sentinel node biopsy. Binomial logistic regression analysis was performed to determine predictors of SSILNs. Multivariate Cox regression analysis was performed to determine the impact of SSILNs on survival in the overall and propensity-score matched patient populations. RESULTS Only 25.3% of patients underwent SSILNs. Increasing patient age, higher comorbidity status, lower pathologic stage, Medicaid insurance, and treatment at a nonacademic facility were independent factors associated with the omission of SSILNs. Omission of SSILNs was an independent predictor of overall mortality, both in the overall patient population after multivariate adjustment, HR = 1.46 [(95% CI: 1.14-1.88), P = 0.003], and in the propensity-score matched adjusted population, HR = 1.59 [(95% CI: 1.20-2.13), P = 0.001]. Limitations include an inability to distinguish biopsy from ILN dissection and those inherent in observational study design. CONCLUSION Utilization of SSILN for penile SCC is low and has not changed significantly since the publication of guidelines in the United States. In particular, nonacademic institutions were less likely to adhere to recommendations for performance of SSILNs. We found the omission of SSILNs is associated with a significant increase in mortality.
Expert Review of Precision Medicine and Drug Development | 2017
Timothy N. Clinton; Aditya Bagrodia; Yair Lotan; Vitaly Margulis; Ganesh V. Raj; Solomon L. Woldu
ABSTRACT Introduction: Prostate cancer is a heterogeneous disease. Existing risk stratification tools based on standard clinlicopathologic variables (prostate specific antigen [PSA], Gleason score, and tumor stage) provide a modest degree of predictive ability. Advances in high-throughput sequencing has led to the development of several novel tissue-based biomarkers that can improve prognostication in prostate cancer management. Areas covered: The authors review commercially-available, tissue-based biomarker assays that improve upon existing risk-stratification tools in several areas of prostate cancer management, including the appropriateness of active surveillance and aiding in decision making regarding the use of adjuvant therapy. Additionally, some of the obstacles to the widespread adoption of these biomarkers and discuss several investigational sources of new biomarkers are discussed. Expert commentary: Work is ongoing to answer pertinent clinical questions in prostate cancer management including which patients should undergo biopsy, active surveillance, receive adjuvant therapy, and what systemic therapy is best in the first-line. Incorporation into novel biomarkers may allow for the incorporation of a ‘personalized’ approach to management. Further validation will be required and questions of cost must be considered before wide scale adoption of these biomarkers. Tumor heterogeneity may impose a ceiling on the prognostic ability of biomarkers using currently available techniques.
The Journal of Urology | 2018
Ezra Margolin; Justin T. Matulay; Gen Li; Xiaosong Meng; Brian Chao; Varun Vijay; Hayley Silver; Timothy N. Clinton; Laura Maria Krabbe; Solomon L. Woldu; Nirmish Singla; Aditya Bagrodia; Vitaly Margulis; William C. Huang; Marc A. Bjurlin; Ojas Shah; Christopher B. Anderson
Purpose: We evaluated the discordance between ureteroscopic biopsy and surgical pathology findings for grading and staging upper tract urothelial carcinoma. We also sought to establish preoperative predictors of aggressive tumors. Materials and Methods: We retrospectively reviewed the records of 314 patients who underwent ureteroscopic biopsy followed by surgical management of upper tract urothelial carcinoma from 2000 to 2016 at a total of 3 institutions. Our primary outcomes were muscle invasive (pT2 or greater) disease at surgical pathology and upgrading of clinical low grade tumors to pathological high grade. Results: At biopsy 61% of the patients had clinical high grade tumors and 21% had subepithelial connective tissue invasion (cT1+). On final pathology 79% of the patients had pathological high grade tumors and 45% had stage pT2 or greater. On multivariate analysis advanced patient age, clinical high grade and cT1+ were independently associated with pT2 or greater. The combined presence of clinical high grade and cT1+ had 86% positive predictive value for muscle invasion while the combined absence of clinical high grade and cT1+ had 80% negative predictive value. The likelihood of missing invasion on biopsy in patients with muscle invasive disease was increased when biopsy fragments were limited to 1 mm or less. Of clinical low grade cases on biopsy 51% were upgraded at surgery. The presence of positive urine cytology was associated with an increased risk of upgrading but this was not statistically significant. Conclusions: Clinical high grade, cT1+ on biopsy and advanced patient age are independent risk factors for muscle invasive upper tract urothelial carcinoma. There is a significant risk of upgrading in patients with clinical low grade tumors on biopsy, especially when urine cytology is positive. The predictive value of biopsy can likely be improved by more extensive ureteroscopic sampling.
The Journal of Urology | 2018
Timothy N. Clinton; Yi Yin; Ganesh V. Raj
B1/AMP-activated protein kinase (LKB1/AMPK) signaling pathway was analyzed using immunoblotting, immunoprecipitation, siRNA silencing and plasmid overexpression. RESULTS: PrLZ increased docetaxel-mediated drug resistance in PCa both in vitro and in vivo. PrLZ was involved in both glucose starvation and docetaxel-induced autophagy. Mechanistic dissection revealed that PrLZ interacted with LKB1 and further inhibited the activation of LKB1/AMPK signals, which negatively contributed to the induction of autophagy. Moreover, PrLZ/LKB1-mediated autophagy conferred resistance to docetaxel-induced cell death and apoptosis both in vitro and in vivo. CONCLUSIONS: These findings identify a novel role of PrLZ in autophagy manipulation and provide new insight into docetaxel chemoresistance in PCa, suggesting a new strategy for treating mCRPC by targeting this newly identified signaling pathway.
Expert Review of Anticancer Therapy | 2018
Yuval Freifeld; Laura-Maria Krabbe; Timothy N. Clinton; Solomon L. Woldu; Vitaly Margulis
ABSTRACT Introduction: Many controversies exist regarding the appropriate management of patients with upper tract urothelial carcinoma (UTUC), including staging, surgical management, use of systemic therapy, and prevention of bladder recurrence. Due to the rarity of this condition, high-level evidence is often lacking and in many cases guidelines are extrapolated from existing evidence on urothelial bladder cancer. Areas covered: This review paper summarizes the evidence on proper diagnosis and staging, surgical techniques, prevention of bladder recurrences, the use of local or systemic treatments in both neoadjuvant and adjuvant settings as well as special consideration for hereditary UTUC. Expert commentary: UTUC is a rare malignancy and slow progress is being made in the acquisition of high-quality evidence in this field. Treatments that facilitate preservation of the kidney are being explored such as advanced endoscopic techniques or partial resection of ureteral disease with seemingly acceptable oncological results. Further prospective evidence is needed.
Clinical Genitourinary Cancer | 2018
Solomon L. Woldu; Justin T. Matulay; Timothy N. Clinton; Nirmish Singla; Yuval Freifeld; Oner Sanli; Laura-Maria Krabbe; Ryan Hutchinson; Yair Lotan; Hans J. Hammers; Raquibul Hannan; James Brugarolas; Aditya Bagrodia; Vitaly Margulis
Background: The optimal timing of targeted therapy (TT) initiation for metastatic renal‐cell carcinoma (mRCC) is not clear. We used a nationwide cancer registry to determine clinical and social factors associated with delayed TT and to evaluate the association of a delayed approach with overall survival (OS). Patients and Methods: We performed a retrospective observational study utilizing the National Cancer Data Base from 2006 to 2012 for patients diagnosed with mRCC (clear‐cell histology) treated with cytoreductive nephrectomy and TT. Time to initiation of TT was defined as early (within 2 months), moderately delayed (2‐4 months), delayed (4‐6 months), and late (> 6 months). Results: Of the 2716 patients included in the analysis, the median (interquartile range) time from diagnosis to initiation of TT was 2.1 (1.3‐3.23) months. A total of 1255 patients (46.2%) had early TT, 1072 patients (39.5%) had moderately delayed TT, 284 patients (10.5%) had delayed TT, and 105 patients (3.9%) had late TT. Delay in TT initiation was not independently associated with OS in multivariable analysis. The time interval from diagnosis to TT initiation was not correlated with time from initiation of TT to death (r = 0.04, P = .08). Conclusion: We found that delayed initiation of TT was not an independent predictor of worse OS. Although this study is subject to limitations of observation study design and selection bias, the results are consistent with the notion that in carefully selected patients, outcomes might not be compromised with initial observation.
Cancer | 2018
Solomon L. Woldu; Oner Sanli; Timothy N. Clinton; Yair Lotan
An assessment of surgical risk is essential for patient counseling and decision making, and it can provide rationale adjustment for patient populations as health care moves from a fee‐for‐service to a value‐based reimbursement model. The modified Frailty Index (mFI) has been proposed as a risk‐stratification tool for radical cystectomy (RC), and the objective of the current study was to validate this potential use of the mFI using an institutional cohort.