Zachary Hamilton’s research while affiliated with St Louis University Hospital and other places

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Publications (137)


Overall survival between radical and partial cytoreductive nephrectomy.
Patient demographics, clinical tumor characteristics, and survival.
Cont.
Surgical outcomes and pathology.
Cox regression for death.

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Utilization of Partial Cytoreductive Nephrectomy in Patients with Metastatic Renal Cell Carcinoma
  • Literature Review
  • Full-text available

September 2024

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25 Reads

Nicholas Hauser

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Julian Giakas

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Hunter Robinson

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[...]

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Zachary Hamilton

Objectives: Cytoreductive nephrectomy for metastatic renal cell carcinoma (mRCC) is a standard of care. Partial nephrectomy (PN) in the setting of metastatic disease is an uncommon occurrence, and we aimed to characterize its utilization in a modern cohort. Methods: The National Cancer Database was reviewed for patients with mRCC from 2010 to 2017. Patients with cTanyNanyM1 who underwent cytoreductive surgery in the form of PN or radical nephrectomy (RN) were compiled. Our primary outcome was survival outcome for patients who underwent PN compared to RN. Secondary outcomes included 30-day readmission, length of stay, and survival outcomes. Results obtained: A total of 13,896 patients with mRCC who underwent cytoreductive surgery were identified. In total, 13,242 underwent RN and 654 underwent PN. The RN population was more likely to have cN positive disease, while the PN population was more likely to have cT1 disease. Length of stay, readmission and 30-day mortality were not significantly different between PN and RN, but overall mortality and 90-day mortality favored PN (p < 0.001). Cox regression for death showed PN with improved overall survival (HR 0.782, p < 0.001). Logistic regression for predictors of cytoreductive PN revealed cT1 and cN0 as significant factors. Overall survival, as seen on KM analysis, identified that PN exhibited improved 2-year (67.1% vs. 52.0%) and 5-year (40.7% vs. 29.2%) overall survival relative to RN (p < 0.001). Conclusions: PN is an infrequent treatment with mRCC and its utilization is stable from 2010 to 2017. Overall survival is significantly better for those undergoing PN, likely due to their favorable oncologic disease characteristics.

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Quality and Readability of Online Health Information on Common Urologic Cancers: Assessing Barriers to Health Literacy in Urologic Oncology

May 2024

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6 Reads

Introduction: A growing number of Americans search online for health information related to urologic oncologic care each year. The American Medical Association recommends that medical information be written at a maximum sixth-grade level in order to be comprehensible by the majority of patients. As such, it is important to assess the quality and readability of online patient education material that patients are being exposed to. Methods: A Google search was performed using the terms "testicular cancer," "prostate cancer," "kidney cancer," and "bladder cancer," and the top 30 results for each were reviewed. Websites were categorized based on their source. Readability was assessed using the Flesch-Kincaid Grade Level, the Gunning Frequency of Gobbledygook, and the Simple Measure of Gobbledygook indices. Quality was assessed using the DISCERN Quality Index (1-5 scale). Results: A total of 91 websites were included in our analysis. On average, online health information pertaining to urologic cancers is written at a 10th- to 11th-grade reading level, which is significantly higher than that of an average American adult and that recommended by the American Medical Association (P < .01). The overall quality of websites was 3.4 ± 0.7, representing moderate to high quality. There was no significant difference in readability based on cancer type or information source. Conclusions: Despite being of moderate to high quality, online patient education materials related to common urologic cancers are often written at a grade level that exceeds the reading level of an average American adult. This presents as a barrier to online health literacy and calls into question the utility of these resources.


Neoadjuvant chemotherapy prior to radical cystectomy for non-muscle invasive bladder cancer: national trends and pathologic outcomes

Background There is a sparsity of literature on treatment outcomes for patients with non-muscle invasive bladder cancer (NMIBC) who received neoadjuvant chemotherapy (NAC). We aim to analyze the outcomes associated with the use of NAC prior to radical cystectomy for NMIBC utilizing the National Cancer Database. Materials/Methods The National Cancer Database bladder dataset was evaluated for patients with NMIBC and known pT staging undergoing RC from 2006–2016. The primary outcome was the utilization of NAC. The secondary outcomes were pathologic down staging to pT0, positive surgical margins, 30-day readmission, and overall survival. Results The proportion of patients receiving NAC prior to radical cystectomy for NMIBC increased from 8.6% in 2006 to 14.8% in 2016. Those who received NAC had significantly higher tumor stages (cT1 vs cTa/is) with 85.7% of patients receiving NAC presenting with cT1 as opposed to only 82% in those not receiving NAC (p < 0.001). Similarly, there were significantly more patients who were cN+ in the NAC group as compared to those who did not receive NAC (5.5% vs. 1.1%, p < 0.001). For patients who received NAC, the rate of downstaging to pT0 was 12.7% as compared to only 3.3% in patients who did not receive NAC (p < 0.001). There was no significant difference comparing the rates of positive margins or 30-day readmissions between groups. On multivariable logistic regression for pathologic downstaging, NAC was significant (OR 4.1, p < 0.05). There was no significant difference in overall survival between patients treated with or without NAC. Conclusion NAC prior to RC in patients with NMIBC has increased in recent years and correlates with tumor downstaging. Further research is requisite to identify patients who obtain the greatest benefit of NAC in the NMIBC setting.



Testicular Cancer and Paraneoplastic Encephalitis: A Review of the Current Literature

May 2024

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68 Reads

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1 Citation

Clinical Genitourinary Cancer

Introduction: Paraneoplastic encephalitis (PE) represents a rare but significant complication in patients with testicular cancer (TC). Given the paucity of comprehensive literature on this topic, our review seeks to consolidate current knowledge and provide evidence-based recommendations for the diagnosis, prognosis, and management of PE in the context of TC. Methods: In adherence to PRISMA guidelines, a systematic literature review was conducted from 1950 to April 2024 using PubMed. The search focused on articles where TC was identified as the primary etiology of PE. The Mixed Methods Appraisal Tool and the Oxford Centre for Evidence-Based Medicine's levels of evidence tool were employed for assessing study quality, and a thematic analysis was conducted to identify trends and patterns. Results: Out of 91 articles identified, 29 met the inclusion criteria, encompassing 5 retrospective chart reviews, 3 case series, and 22 case reports. Findings indicate that PE symptoms can manifest at any stage of TC—before tumor detection, during treatment, or even years post-treatment. A notable observation was the frequent oversight of microscopic testicular tumors in ultrasound imaging, leading to diagnostic delays. The outcomes of PE in the context of TC were diverse, reflecting the heterogeneity of the studies included. Conclusion: PE, although rare, is a critical consideration in patients with TC presenting with neuro-psychiatric symptoms. Early recognition and appropriate diagnostic workup, including consideration for microscopic neoplasms, are essential for timely intervention and improved patient outcomes.


Figure 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart.
Leptomeningeal metastases in prostate cancer: A review of the current literature

March 2024

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61 Reads

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1 Citation

Current Urology

Leptomeningeal metastasis/leptomeningeal carcinomatosis (LMC; terms used interchangeably) is an inflammatory complication of primary tumors that involves the spread of the disease to the meninges (specifically the arachnoid and pia maters) and spinal cord. In the United States, approximately 110,000 new cases are diagnosed each year, and the prognosis is usually poor. Complications of LMC include cognitive impairment, cranial nerve dysfunction, ischemic stroke, and mortality. The survival times of untreated and treated LMC are approximately 4-6 weeks and 2-4 months, respectively. Leptomeningeal carcinomatoses are usually metastatic cancers that spread to the central nervous system. Although lung and breast cancers have a clearly defined relationship with LMC, it remains unclear whether prostate cancer (PC) is also directly associated with LMC. To determine whether such association exists, we conducted a PubMed review of the literature on patients with PC with coexisting LMCs. Our search yielded 23 case reports of patients with preexisting PC who developed LMC. In addition, 2 retrospective cohort studies were examined. Various findings were identified in the revised cases and studies. The first 3 findings were related to the progression of the disease: patients presenting with neurological disease symptoms were in remission from PC for 7 years on average, LMCs tended to occur after other cancer diagnoses, and the disease had already rapidly progressed by the time the symptoms were present. Regarding diagnosis, the major finding was that most LMCs were detected by magnetic resonance imaging (which does not detect early dissemination), and it was suggested that single-photon emission computed tomography or positron emission tomography imaging could be used for earlier detection. Finally, in terms of treatment, the main finding was that treatment was palliative rather than curative and that prognosis remained poor despite treatment. On the basis of these results, we recommend for individuals with risk factors, such as high-grade PC and hormonal PC, to be evaluated on a case-by-case basis for increased surveillance of LMC development.


How Agent Orange impacts prostate cancer risk, pathology, and treatment outcomes

Current Urology

Between 2.6 and 3.8 million veterans served in Vietnam while the US military dispersed Agent Orange (AO), although the exact number of exposed individuals is unknown. Agent Orange, an herbicide, is a known risk factor for various cancers, including sarcoma and leu-kemia, but less is known about its link with prostate cancer (PC). Prostate cancer is the most commonly diagnosed malignancy in men and the fifth most common cause of cancer-related death in men worldwide. In 2023, approximately 288,300 patients will be given a diagnosis of PC, and an estimated 34,700 fatalities will occur in the United States. However, whether the pathologic characteristics of PC among those exposed to AO differ from those in the general population remains unclear. Our review synthesizes the literature regarding the impact of AO exposure on PC incidence and disease course. A comprehensive PubMed literature search of articles published beginning in 1950 was performed using the primary search terms "Agent Orange," "TCDD," and "tetrachlorodibenzodioxin" and the secondary search terms "prostate cancer" or "prostate neoplasm." The search was limited to studies that focused on human participants and were published in English. Four authors thoroughly reviewed the retrieved articles for relevancy to the study aims: discussion of PC diagnosis, prognosis, or management among patients exposed to AO. Of 108 studies identified in our search, 13 were included in this systematic review. Findings within studies concerning AO exposure with relation to PC incidence, age at diagnosis or treatment initiation, and PC severity seemed to be mixed and generally conflicting. However, the literature seems to indicate that there are no significant differences in survivorship between exposed and unexposed veterans who are given a diagnosis of PC. Given these heterogeneous outcomes, the evidence does not encourage a significantly different approach to the diagnosis and management of PC for veterans exposed to AO. Clinicians should make case-by-case decisions regarding PC screening and potential treatment options for this patient group, weighing clinical suspicion against the harms of diagnostic workup and treatment.


A Rare Variant of Zinner Syndrome Involving Ectopic Ureteral Implantation into the Seminal Vesicle Causing Recurrent Epididymitis

March 2024

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41 Reads

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2 Citations

Zinner syndrome is a rare congenital anomaly characterized by a triad of renal dysgenesis/agenesis, cysts in the ipsilateral seminal vesicle, and ejaculatory duct obstruction. Though often diagnosed in infancy, the diagnoses can be incidentally found in adults who present with nonspecific genitourinary symptoms including dysuria, ejaculatory dysfunction, or genital pain. We present an unusual case of a 29-year-old male patient who presented to the emergency department with recurrent testicular pain and hematospermia and was found to have an atrophic right kidney with an ectopic ureter implanting into a cystic seminal vesicle. These findings were consistent with a rare subvariant of Zinner syndrome only previously described four times in the literature. We performed a robotic-assisted laparoscopic ectopic nephroureterectomy with sparing of his seminal vesicle. To our knowledge, this is the first report to describe the safe and effective use of robotic surgery in this setting to remove affected anatomy while preserving the patient’s seminal vesicle.



Citations (52)


... PLE secondary to germ cell testicular tumors is well documented and associated with a variety of autoantibodies such as anti-Ma1/2, anti-KLHL11, and anti-TA. 3 Using both PubMed and Ovid MEDLINE, we searched the keywords "Sertoli cell tumor," "non-germ cell tumor," and "paraneoplastic limbic encephalitis" to assess previous cases examining the association between PLE and non-germ cell tumors. Our search included the time frame from January 1st, 1946 to February 14th, 2025 and included all forms of publication types. ...

Reference:

Paraneoplastic Limbic Encephalitis Secondary to Sertoli Cell Testicular Tumor: A Case Report
Testicular Cancer and Paraneoplastic Encephalitis: A Review of the Current Literature
  • Citing Article
  • May 2024

Clinical Genitourinary Cancer

... It comprises a triad: unilateral renal agenesis, ipsilateral seminal vesicle cysts, and ejaculatory duct obstruction. These anomalies originate between the 4th and 13th gestational weeks due to ureteric bud maldevelopment and subsequent failure to induce the metanephric blastema [2]. The resultant abnormalities involve absent renal tissue and cystic or obstructive changes in the ipsilateral seminal vesicle and ejaculatory duct [3]. ...

A Rare Variant of Zinner Syndrome Involving Ectopic Ureteral Implantation into the Seminal Vesicle Causing Recurrent Epididymitis

... In addition, tumor stage and marital status, as independent risk factors, had a significant impact on the prediction of CSM. Receiving chemotherapy appeared to significantly reduce the odds of developing CSM in elderly BCa patients after RC, whereas the effect of whether or not they received Transl Cancer Res 2025;14 (3) A C B D radiotherapy was 0. It has been shown that the use of RC combination chemotherapy is associated with greater pathologic downstaging in all age groups, including in elderly patients (22). For muscle-invasive BCa, it has been shown that neoadjuvant chemotherapy should be given whenever the patient can tolerate cisplatin-based chemotherapy (23,24). ...

Age related trends in the utilization of neoadjuvant chemotherapy for muscle invasive bladder cancer
  • Citing Article
  • January 2024

Urologic Oncology Seminars and Original Investigations

... Consistent with previously reported NCDB studies regarding systemic therapies in metastatic ccRCC, targeted therapy was defined as the receipt of single or multiagent systemic chemotherapy, immunotherapy was defined as the receipt of systemic immunotherapy, and combination therapy was defined as meeting the criteria for both targeted and immunotherapy simultaneously as first-line therapy [17][18][19][20]. Systemic therapies are classified using the SEER*Rx Interactive Drug Database and coded into the NCDB without identifying specific drug names [21]. ...

Survival in Metastatic Renal Cell Carcinoma Treated With Immunotherapy and Stereotactic Radiation Therapy or Immunotherapy Alone: A National Cancer Database Analysis

Advances in Radiation Oncology

... Despite current guideline recommendations for NAC, 5,6 our study reports NAC utilization at only 35%, which is only slightly higher than other recent studies but still low considering it is the standard of care. 27,28 Interestingly, despite the low utilization of NAC, these data suggest that receipt of NAC does not change patients' preference for adjuvant therapy, but instead suggests that the preferences of adjuvant treatment attributes may vary based on prior treatment history. ...

PD44-05 AGE RELATED TRENDS IN THE UTILIZATION OF NEOADJUVANT CHEMOTHERAPY FOR MUSCLE INVASIVE BLADDER CANCER
  • Citing Article
  • April 2023

The Journal of Urology

... The mean 90-day mortality following RC for patients aged ≥80 years in database studies was 11% compared to 3% in non-database studies. Heterogeneity was high between the registry studies with Hounsome et al. [43] and Liberman et al. [51] describing 9% 90-day mortality compared to 13% and 14% mortalities for Ray et al. [68], Fedeli et al. [33] and Jaeger et al. [47]. Table S1 demonstrates basic study data from these database studies to explore the reported heterogeneity between studies. ...

Perioperative outcomes of open versus robot-assisted radical cystectomy in octogenarians: a population based analysis

Journal of Robotic Surgery

... However, questions remain whether such findings have an impact on oncological outcomes [21]. While it is logical that delaying diagnosis and treatment may hamper the oncological outcome, a recent study [22] showed that the increased surgical wait time due to the COVID pandemic did not increase the risk of node-positive prostate cancer. It is, however, worth mentioning that this may be true for low-intermediate-risk PCa but may not apply to high-risk PCa. ...

Increasing surgical wait time does not increase the risk of node positive prostate cancer: Implications for surgical planning during the COVID-19 pandemic and beyond

Frontiers in Urology

... Based on histological, immunohistochemical, and imaging examination results, the patient was diagnosed with right renal pelvic carcinoma with sarcomatoid differentiation, with a tumor stage of T 1 N 0 M 0 .Uroepithelial carcinoma is mainly originated from the epithelial cells of the urothelium, and most of them are found in the bladder, but about 25% of the patients contain various subtypes such as variant histology (VH), which includes various subtypes such as squamous differentiation, adenoid differentiation, neuroendocrine differentiation, and sarcomatoid differentiation. Pure variant histology types are very rare and account for only 5% of upper urinary tract tumors (3).Malignant tumors occurring in the renal pelvis are most commonly associated with migratory cell carcinoma and according to Mousavi SE et al, the incidence of renal pelvis carcinoma increases with age, especially after the age of 55 years where the increase in incidence is more pronounced, and peaks in the age group of 80 -84 years for both males and females, with both males having a higher incidence than females (4). The more common symptoms of clinical presentation are painless hematuria, pain and palpable mass and the common complications associated with it include kidney stones (5,6). ...

Variant histology in upper tract carcinomas: Analysis of the National Cancer Database
  • Citing Article
  • February 2023

Urologic Oncology Seminars and Original Investigations

... RALP offers reduced blood loss and length of stay [10]. However, case series and voluntary registries have suggested that RALP exposes patients to unique ophthalmic risks, including corneal abrasion, subconjunctival emphysema, retinal vascular occlusion and ischaemic optic neuropathy [11][12][13][14]. Visual loss may be permanent. ...

BUBBLING OVER: A CASE OF SUBCONJUNCTIVAL EMPHYSEMA AND PNEUMOMEDIASTINUM FOLLOWING LAPAROSCOPIC PROSTATECTOMY
  • Citing Article
  • October 2022

Chest

... Aside from the match, urology is one of the leading specialties that has utilized social media such as Twitter, Instagram, Facebook, and now TikTok as an opportunity for education of patients, students, and physicians. An analysis of urology residency program presence on social media found that 86% of urology residency programs have a Twitter account, 39% have an Instagram account, and 34% have a Facebook account [11]. ...

Analyzing the growth in social media proliferation in academic urology: Associations between program ranking and social media footprint
  • Citing Article
  • September 2022

Canadian Urological Association journal = Journal de l'Association des urologues du Canada