Role of Gut Microbiome in Neoadjuvant Chemotherapy Response in Urothelial Carcinoma: A Multi-institutional Prospective Cohort Evaluation.

Neoadjuvant chemotherapy (NAC) is linked with clinical advantages in urothelial carcinoma for patients with muscle-invasive bladder cancer (MIBC). Despite comprehensive research into the influence of tumor mutation expression profiles and clinicopathologic factors on chemotherapy response, the role of the gut microbiome (GM) in bladder cancer chemotherapy response remains poorly understood. This study examines the variance in the GM of patients with bladder cancer compared with healthy adults, and investigates GM compositional differences between patients who respond to chemotherapy versus those who exhibit residual disease.Our study reveals distinct clustering, effectively separating the bladder cancer and healthy cohorts. However, no significant differences were observed between chemotherapy responders and nonresponders within community subgroups. Machine learning models based on responder status outperformed clinical variables in predicting complete response (AUC 0.88 vs. AUC 0.50), although no single microbial species emerged as a fully reliable biomarker.The evaluation of short chain fatty acid (SCFA) concentration in blood and stool revealed no correlation with responder status. Still, SCFA analysis showed a higher abundance of Akkermansia (rs = 0.51, P = 0.017) and Clostridia (rs = 0.52, P = 0.018), which correlated with increased levels of detectable fecal isobutyric acid. Higher levels of fecal Lactobacillus (rs = 0.49, P = 0.02) and Enterobacteriaceae (rs = 0.52, P < 0.03) correlated with increased fecal propionic acid.In conclusion, our study constitutes the first large-scale, multicenter assessment of GM composition, suggesting the potential for a complex microbial signature to predict patients more likely to respond to NAC based on multiple taxa. SIGNIFICANCE: Our study highlights results that link the composition of the GM to the efficacy of NAC in MIBC. We discovered that patients with higher levels of Bacteroides experienced a worse response to NAC. This microbial signature shows promise as a superior predictor of treatment response over traditional clinical variables. Although preliminary, our findings advocate for larger, more detailed studies to validate these associations.

Trends, Cost, and Predictors of Local Hemostatics Use in Major Urological Surgery.

INTRODUCTION: The national usage and cost trends associated with hemostatic agents in major urologic procedures remain unknown. This study aims to describe the trends, costs, and predictors of local hemostatic use in major urologic surgeries. METHODS: We utilized the Premier Healthcare Database to analyze 385,261 patient encounters between 2000 and 2020. Our primary objective was to describe the usage patterns of topical hemostatic agents in open and laparoscopic/robotic major urological surgeries. The data from the last 5 years (2015-2020) were used to characterize specific cost trends, and multivariable regression analysis was performed to identify predictors of hemostatic agent use in relation to surgical approach, patient, and hospital characteristics. RESULTS: By 2020, at least 1 topical hemostatic agent was used in 37.3% (95% CI: 35.5-39.1) of laparoscopic/robotic prostatectomies and 30.7% (95% CI: 24.2-37.1) of open prostatectomies; 60.8% (95% CI: 57.6-64.1) of laparoscopic/robotic partial nephrectomies and 55.9% (95% CI: 47.3-64.5) of open partial nephrectomies; 40.7% (95% CI: 36.9-44.3) of laparoscopic/robotic radical nephrectomies and 43.2% (95% CI: 38.8-47.6) of open radical nephrectomies; and 40.52% (95% CI: 35.02-46.02) of open radical cystectomies. For the 2015-2020 cohort, predictors for hemostatic agent use varied by surgery type and included gender, race, surgical approach, insurance coverage, geographical location, urbanicity, and attending volume. The cost of the hemostatic agent accounted for less than 1.6% of the total cost of hospitalization for each procedure. CONCLUSIONS: The use of hemostatic agents in major urologic surgeries has grown over the past 2 decades. For all procedures, the specific cost of using a hemostatic agent constitutes a small fraction of the total hospitalization cost and does not vary significantly between open and laparoscopic/robotic approaches. Some patient, surgeon, and hospital characteristics are highly correlated with their use.

Prostate cancer genetic alterations in Hispanic men.

BACKGROUND: Differences in DNA alterations in prostate cancer among White, Black, and Asian men have been widely described. This is the first description of the frequency of DNA alterations in primary and metastatic prostate cancer samples of self-reported Hispanic men. METHODS: We utilized targeted next-generation sequencing tumor genomic profiles from prostate cancer tissues that underwent clinical sequencing at academic centers (GENIE 11th). We decided to restrict our analysis to the samples from Memorial Sloan Kettering Cancer Center as it was by far the main contributor of Hispanic samples. The numbers of men by self-reported ethnicity and racial categories were analyzed via Fisher's exact test between Hispanic-White versus non-Hispanic White. RESULTS AND LIMITATIONS: Our cohort consisted of 1412 primary and 818 metastatic adenocarcinomas. In primary adenocarcinomas, TMPRSS2 and ERG gene alterations were less common in non-Hispanic White men than Hispanic White (31.86% vs. 51.28%, p = 0.0007, odds ratio [OR] = 0.44 [0.27-0.72] and 25.34% vs. 42.31%, p = 0.002, OR = 0.46 [0.28-0.76]). In metastatic tumors, KRAS and CCNE1 alterations were less prevalent in non-Hispanic White men (1.03% vs. 7.50%, p = 0.014, OR = 0.13 [0.03, 0.78] and 1.29% vs. 10.00%, p = 0.003, OR = 0.12 [0.03, 0.54]). No significant differences were found in actionable alterations and androgen receptor mutations between the groups. Due to the lack of clinical characteristics and genetic ancestry in this dataset, correlation with these could not be explored. CONCLUSION: DNA alteration frequencies in primary and metastatic prostate cancer tumors differ among Hispanic-White and non-Hispanic White men. Notably, we found no significant differences in the prevalence of actionable genetic alterations between the groups, suggesting that a significant number of Hispanic men could benefit from the development of targeted therapies.

Trends over 20 years of antimicrobial prophylaxis for artificial urinary sphincter surgery.

INTRODUCTION AND OBJECTIVE: Perioperative antimicrobial prophylaxis is crucial for prevention of prosthesis and patient morbidity after artificial urinary sphincter (AUS) placement. While antibiotic guidelines exist for many urologic procedures, adoption patterns for AUS surgery are unclear. We aimed to assess trends in antibiotic prophylaxis for AUS and outcomes relative to American Urological Association (AUA) Best Practice guidelines. METHODS: The Premier Healthcare Database was queried from 2000 to 2020. Encounters involving AUS insertion, revision/removal, and associated complications were identified via ICD and CPT codes. Premier charge codes were used to identify antibiotics used during the insertion encounter. AUS-related complication events were found using patient hospital identifiers. Univariable analysis between hospital/patient characteristics and use of guideline-adherent antibiotics was done via chi-squared and Kruskal-Wallis tests. A multivariable logistic mixed effects model was used to assess factors related to the odds of complication, specifically the use of guideline-adherent versus nonadherent regimens. RESULTS: Of 9775 patients with primary AUS surgery, 4310 (44.1%) received guideline-adherent antibiotics. The odds of guideline-adherent regimen use increased 7.7% per year with 53.0% (830/1565) receiving guideline-adherent antibiotics by the end of the study period. Patients with guideline-adherent regimens had a decreased risk of any complication (odds ratio [OR]: 0.83, 95% confidence interval [CI]: 0.74-0.93) and surgical revision (OR: 0.85, 95% CI: 0.74-0.96) within 3 months; however, no significant difference in infection within was noted (OR: 0.89, 95% CI: 0.68-1.17) within 3 months. CONCLUSIONS: Adherence to AUA antimicrobial guidelines for AUS surgery appears to have increased over the last two decades. While guideline-adherent regimens were associated with decreased risk of any complication and surgical intervention, no significant association was found with risk of infection. Surgeons appear to be increasingly following AUA recommendations for antimicrobial prophylaxis for AUS surgery, however, further level 1 evidence should be obtained to demonstrate conclusive benefit of these regimens.

How Female Is the Future of Urology? Projecting Various Trajectories of the United States Urology Workforce.

OBJECTIVE: To project the number and proportion of women in the urology workforce using recent demographic trends and develop an app to explore updated projections using future data. METHODS: Demographic data were obtained from AUA Censuses and ACGME Data Resource Books. The proportion of female graduating urology residents was characterized with a logistic growth model. "Stock and Flow" models were used to project future population numbers and proportions of female practicing urologists, accounting for trainee demographics, retirement trends, and growth in the field. RESULTS: Assuming growth in urology graduate numbers and continued logistic growth in the proportion of women, 10,957 practicing urologists (38%) will be female by 2062. If the rate of women entering urology residency stagnates, 7038 urologists (24%) will be female. If the retirement rates for women in urology change to mirror those of men and the proportion of female residents continues to experience logistic growth, 11,178 urologists (38%) will be female. An interactive app was designed to allow for a range of assumptions and future data: https://stephenrho.shinyapps.io/uro-workforce/. CONCLUSION: Workforce projections should incorporate recent growth in numbers of female residents. If current growth continues, 38% of urologists will be female by 2062. The app allows for exploration of different scenarios and can be updated with new data. The projections demonstrate the need for targeted efforts to recruit women into urology, address disparities within the field, and work toward retaining female urologists. We must continue working toward an equitable future workforce that can address the impending shortage of urologists.

Bladder and Kidney Cancer Diagnosis and Survival Increase With Medicare Eligibility at Age 65.

INTRODUCTION: Medicare eligibility at 65 has been associated with increased diagnosis and survival for certain cancers due to greater health care utilization. We aim to assess for a similar "Medicare effect" for bladder and kidney cancers, which has not been previously established. METHODS: Patients diagnosed with bladder or kidney cancer from 2000-2018 at ages 60-69 years were identified with the Surveillance, Epidemiology, and End Results database. We used age-over-age percent change calculations to characterize trends in cancer diagnoses focusing on patients aged 65. Multivariable Cox models were used to compare cancer-specific mortality across ages at diagnosis. RESULTS: We identified 63,960 patients diagnosed with bladder cancer and 52,316 diagnosed with kidney cancer. Age-over-age change in diagnosis was highest for patients aged 65 compared to all other ages for both cancers (P < .01 for both). Stratified by stage, patients aged 65 had a higher age-over-age change than those aged 61-64 or 66-69 for in situ (P = .01, P < .01, respectively), localized (P = .03, P = .01), and regional (P = .02, P = .02) bladder cancer and localized (P = .01, P = .01) kidney cancer. Bladder cancer patients aged 65 had lower cancer-specific mortality than patients aged 66 (HR = 1.17, P = .01) and 69 (HR = 1.18, P = .01), while kidney cancer patients aged 65 had lower mortality than patients aged 64 (HR = 1.18, P < .01) and 66-69. CONCLUSIONS: The age of 65, marking the onset of Medicare eligibility, is associated with more diagnoses of bladder and kidney cancer. Patients diagnosed at age 65 demonstrate decreased bladder and kidney cancer-specific mortality.

Cost-effectiveness analysis of arterial catheter insertion on robotic-assisted laparoscopic prostatectomy.

INTRODUCTION: To evaluate the utility, outcomes, and cost of arterial line placement in a single institution cohort of patients undergoing robotic-assisted laparoscopic prostatectomy (RALP). MATERIALS AND METHODS: A retrospective chart review was performed at a large tertiary care center from July 2018 through January 2021. Hospital costs and cost-effective analysis was performed on patients with and without arterial line placement. Means with standard deviations were used to report continuous variables, while numbers and percentages were utilized to describe categorical variables. T-tests and Chi-square tests compared categorical and continuous variables across study cohorts, respectively. Multivariable analyses were used to examine the association between A-line placement and outcomes as mentioned above adjusting for the effect of other co-variables. RESULTS: Among the 296 included patients, 138 (46.6%) had arterial lines. No preoperative patient characteristic predicted arterial line placement. Rates of complications and re-admissions were not statistically significant between the two groups. Arterial line use was associated with higher volumes of intraoperative fluid administration, as well as a longer hospital length of stay. Total cost and operative time did not significantly differ between cohorts, but arterial line placement increased variability of these factors. CONCLUSION: The use of arterial lines in patients undergoing RALP is not necessarily guideline-driven and does not decrease the rate of perioperative complications. However, it is associated with longer length of stay and increases variability in charge. These data show that the surgical team and anesthesia team should critically evaluate the need for arterial line placement in patients undergoing RALP.

Evaluating the readability of online testosterone search results.

With the budding interest in testosterone therapy (TTh), online health information plays a significant role in patients' health care decisions. Therefore, we evaluated the source and readability of web-based information available to patients regarding TTh on Google. From Google search terms "Testosterone Therapy" and "Testosterone Replacement", 77 unique sources were identified. Sources were categorized as Academic, Commercial, Institutional, or Patient Support, then evaluated using validated readability and English language text assessment tools: the Flesch Reading Ease score, Flesch Kincade, Gunning Fog, Simple Measure of Gobbledygook (SMOG), Coleman-Liau Index and Automated Readability index. The average grade level for understanding academic sources was 16 (college senior); commercial, institutional, and patient support sources were 13 (college freshman); 8 and 5 grade levels, respectively, above the average U.S. adult. Patient support sources were most prevalent, while commercial sources were the least at 35 and 14%, respectively. The average reading ease score was 36.8, indicative of difficult-to-read material overall. These results indicate that the most immediate online sources for TTh information exceed the average reading level of most adults within the U.S., hence more effort should be taken to publish accessible and readable material to improve patient health literacy.

Role of Gut Microbiome in Neoadjuvant Chemotherapy Response in Urothelial Carcinoma: A Multi-Institutional Prospective Cohort Evaluation.

Treatment with neoadjuvant chemotherapy (NAC) in muscle invasive bladder cancer (MIBC) is associated with clinical benefit in urothelial carcinoma. While extensive research evaluating role of tumor mutational expression profiles and clinicopathologic factors into chemoresponse has been published, the role of gut microbiome (GM) in bladder cancer in chemoresponse has not been thoroughly evaluated. A working knowledge of the microbiome and its effect on all forms of cancer therapy in BC is critical. Here we examine gut microbiome of bladder cancer patients undergoing NAC. Overall, there was no significant difference in alpha and beta diversity by responder status. However, analysis of fecal microbiome samples showed that a higher abundance of Bacteroides within both institutional cohorts during NAC was associated with residual disease at the time of radical cystectomy regardless of chemotherapy regimen. Group community analysis revealed presence of favorable microbial subtypes in complete responders. Finally, fecal microbial composition outperformed clinical variables in prediction of complete response (AUC 0.88 vs AUC 0.50), however, no single microbial species could be regarded as a fully consistent biomarker. Microbiome-based community signature as compared to single microbial species is more likely to be associated as the link between bacterial composition and NAC response.

Treatment patterns and survival of low and intermediate-risk prostate cancer in end-stage kidney disease: A retrospective population cohort study.

BACKGROUND: In accordance with guidelines, observation with or without active surveillance for low-risk prostate cancer increased in recent years in the general population. We compared treatment patterns and mortality for low- and intermediate-risk prostate cancer and mortality rates among end-stage kidney disease (ESKD) and non-ESKD patients. METHODS: This is a retrospective population-based observational cohort study of Surveillance, Epidemiology, and End Results-Medicare data of men aged 66 years and older with localized prostate cancer (2004-2015). ESKD status was determined using Medicare billing codes. Multivariable logistic regression models and Cox-proportional hazards models were used to study definitive treatment patterns and mortality, respectively. RESULTS: For low-risk prostate cancer, dialysis patients (N = 83) had lower but not statistically significant odds (OR, 0.74; 95% CI: 0.48-1.16) of receiving definitive treatment than non-ESKD patients (N = 24,935). For those with intermediate-risk prostate cancer, dialysis patients (N = 254) had lower odds to receive definitive treatment (OR, 0.54; 95% CI: 0.42-0.72) than non-ESKD patients (N = 60,883). From 2004-2010 to 2011-2015, for patients with low-risk prostate cancer, while the receipt of definitive treatment for non-ESKD patients trended down from 72% to 48%, it trended up for dialysis patients from 55% to 65%. Kidney transplant patients (N = 33 for low-risk and N = 91 for intermediate-risk) had lower rates of definitive treatment for low-risk and similar rates of treatment for intermediate-risk prostate cancer compared to non-ESKD patients. CONCLUSIONS: The disparity in definitive treatment rates for low-risk prostate cancer among dialysis patients exists despite their high mortality, compared to the general population.

National Adherence to Guidelines for Antimicrobial Prophylaxis for Patients Undergoing Radical Cystectomy.

PURPOSE: The sentinel reference for antibiotic prophylaxis for radical cystectomy with ileal conduit in the AUA Guidelines reports data from 2003-2013 and has not been updated in the interim. Here, we assess adherence to antibiotic prophylaxis guidelines among patients undergoing radical cystectomy with ileal conduit for bladder cancer using a large national database. As a secondary objective, we assess the association between antimicrobial use and postoperative infection during the index admission following cystectomy. MATERIALS AND METHODS: The Premier Healthcare Database was queried for all patients undergoing cystectomy with ileal conduit with diagnosis of bladder cancer between 2015 and 2020. Antibiotics used and the duration of use was determined by charge codes and grouped as guidelines-based or not according to 2019 AUA Guidelines. Association with infectious complications was assessed by logistic mixed effects regression models. RESULTS: Among 6,708 patients undergoing cystectomy with ileal conduit, only 28% (1,843/6,708) were given prophylaxis according to AUA guidelines; 1.8% (121/6,708) of patients received an antifungal and 37% (2,482/6,708) received extended duration prophylaxis beyond postoperative day 1. Patients who received guidelines-based prophylaxis were less likely to be diagnosed with a urinary tract infection (21% vs 24%, P = .04), pyelonephritis (5.1% vs 7.7%, P < .001), bacterial infection (24% vs 27%, P = .03), or pneumonia (12% vs 17%, P < .001). There was no statistically significant difference in clostridium difficile infection between guidelines-based and nonguidelines-based prophylaxis (3.2% vs 3.7%, P = .32). In a multivariable logistic regression adjusting for age, race, insurance, and hospital and provider characteristics, nonguideline antibiotic prophylaxis (OR 1.27 [1.12, 1.43], P < .001) was associated with an increased odds of infectious events, whereas a robotic approach (OR 0.82 [0.73, 0.92], P < .001) was associated with lower odds. CONCLUSIONS: Seventy-three percent of patients fail to receive guideline-based antibiotic prophylaxis when undergoing radical cystectomy with conduit, which was largely driven by extended duration antibiotic use. Despite the shorter duration of antibiotics, we found that guideline-based prophylaxis was associated with a 25% decrease in the odds of infectious complications. While residual confounding is possible, these data support current AUA guidelines and suggest a need for outreach to improve guideline adherence.

Trends in Antimicrobial Prophylaxis for Inflatable Penile Prosthesis Surgery From a Large National Cohort.

OBJECTIVE: To assess changes in antibiotic prophylaxis for inflatable penile prosthesis surgery following publication of the American Urological Association (AUA) Best Practice Statement in April 2008. MATERIALS AND METHODS: The Premier Healthcare Database was queried for inflatable penile prosthesis surgeries from January 2000 to March 2020. The primary outcome was administration of an AUA-adherent antimicrobial regimen and secondary outcome was 90-day explant. Piecewise linear regression was used to compare antimicrobial trends before vs after guideline publication. Multivariable logistic regression models were constructed for primary and secondary outcomes. RESULTS: A total of 26,574 patients who underwent inflatable penile prosthesis surgery were identified, of whom 17,754 (67%) received AUA-adherent antibiotics. After guideline publication, there was a 42% relative increase in AUA-adherent regimen usage, with an increase in the usage trend on piecewise linear regression (from 0.1% to 0.8% of encounters per quarter, R2 = 0.75, P < .001). Increased usage trends were also observed for gentamicin (from 0.0% to 1.0% of encounters per quarter, R2 = 0.84, P < .001) and vancomycin (0.1%-0.7%, R2 = 0.77, P < .001). On multivariable regression, odds of AUA-adherence increased after guideline publication (OR: 1.67, 95% CI: 1.54-1.80, P < .001) and with surgery by a high-volume surgeon (OR: 2.21, 95% CI: 2.07-2.35, P < .01). Nonadherence to an AUA-recommended regimen with use of nonstandard antibiotics (OR: 1.16, 95% CI: 0.78-1.71, P = .5) or excess antibiotics (OR: 0.91, 95% CI: 0.62-1.30, P = .6) was not independently associated with increased risk of 90-day explant. CONCLUSIONS: Publication of the AUA Best Practice Statement was associated with subsequent increases in the usage of guideline-adherent antibiotic regimens, particularly vancomycin and gentamicin, despite absence of level-1 evidence supporting this combination.

Characterization of Changes in Penile Microbiome Following Pediatric Circumcision.

BACKGROUND: While microbiome and host regulation contribute independently to many disease states, it is unclear how circumcision in pediatric population influences subsequent changes in penile microbiome. OBJECTIVE: Our study aims to analyze jointly paired taxonomic profiles and assess pathways implicated in inflammation, barrier protection, and energy metabolism. DESIGN, SETTING, AND PARTICIPANTS: We analyzed 11 paired samples, periurethral collection, before and after circumcision, to generate microbiome and mycobiome profiling. Sample preparation of 16S ribosomal RNA and internal transcribed spacer sequencing was adapted from the methods developed by the National Institutes of Health Human Microbiome Project. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We obtained the predictive functional attributes of the microbial communities between samples using Silva-Tax4Fun and the Greengenes-Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) approach. The predictive functioning of the microbial communities was determined by linearly combining the normalized taxonomic abundances into the precomputed association matrix of Kyoto Encyclopedia of Genes and Genomes orthology reference profiles. RESULTS AND LIMITATIONS: Several notable microbiome and mycobiome compositional differences were observed between pre- and postcircumcision patients. Pairwise comparisons across taxa revealed a significant decrease (p < 0.05, false discovery rate corrected) of microbiome organisms (Clostridiales, Bacteroidales, and Campylobacterales) and mycobiome (Saccharomycetales and Pleosporales) following circumcision. A total of 14 pathways were found to differ in abundance between the pre- and postcircumcision groups (p < 0.005, false discovery rate <0.1 and linear discriminant analysis score >3; five enriched and nine depleted). The pathways reduced after circumcision were mostly involved with amino acid and glucose metabolism, while pathways prior to circumcision were enriched in genetic information processing and transcription processes. As expected, enrichment in methyl-accepting chemotaxis protein, an integral membrane protein involved in directed motility of microbes to chemical cues and environment, occurred prior to circumcision, while the filamentous hemagglutinin pathway (a strong immunogenic protein) was depleted after circumcision CONCLUSIONS: Our results offer greater insight into the host-microbiota relationship of penile circumcision and may serve to lay the groundwork for future studies focused on drivers of inflammation, infection, and oncogenesis. PATIENT SUMMARY: Our study showed a significant reduction in bacteria and fungi after circumcision, particularly anaerobic bacteria, which are known to be potential inducers of inflammation and cancer. This is the first study of its kind showing the changes in microbiome after circumcision, and some of the changes that occur in healthy infants after circumcision that may explain the differences in cancer and inflammatory disorders in adulthood.

Variability of Prostate MRI Charges Among U.S. Hospital-Based Facilities.

The Premier Healthcare Database was used to assess charge variation for prostate MRI examinations in U.S. hospitals from January 2010 to March 2020. In 552 facilities performing 37,073 examinations, the median charge per examination was $4419 with 26-fold variation between the lowest ($593) and highest ($15,150) median facility charges. In multilevel linear regression analysis, interfacility variation explained 63.9% of charge variation. Patients may be charged vastly different prices for prostate MRI depending on the facility.

Review of Robotic-Assisted Radical Nephrectomy with Inferior Vena Cava Thrombectomy in Renal Cell Carcinoma.

PURPOSE OF REVIEW: Recent advances in minimally invasive technology have compelled surgeons to perform nephrectomy with inferior vena cava thrombectomy using robotic assistance. Here, we aim to review the data comparing open versus robot-assisted nephrectomy with IVC thrombectomy, as well as review operative robotic techniques for nephrectomy with IVC thrombectomy. RECENT FINDINGS: Over the last decade, there have been increasing reports of successful robotic-assisted IVC thrombectomy among skilled robotic surgeons, with case series detailing operative technique, as well as operative and oncologic outcomes for levels I-IV caval thrombus. While there is immense promise in the future of robotic-assisted IVC thrombectomy, further studies with direct comparison to open surgical intervention will be needed to ensure the oncologic principles and outcomes are non-inferior.

Human Gut Mycobiome and Fungal Community Interaction: The Unknown Musketeer in the Chemotherapy Response Status in Bladder Cancer.

Background: Until recently, the properties of microbiome and mycobiome in humans and its relevance to disease have largely been unexplored. While the interest of microbiome and malignancy over the past few years have burgeoned with advent of new technologies, no research describing the composition of mycobiome in bladder cancer has been done. Deciphering of the metagenome and its aggregate genetic information can be used to understand the functional properties and relationships between the bacteria, fungi, and cancer. Objective: The aim of this project is to characterize the compositional range of the normal versus bladder cancer mycobiome of the gut. Design setting and participants: An internal transcribed spacer (ITS) survey of 52 fecal samples was performed to evaluate the gut mycobiome differences between noncancer controls and bladder cancer patients. Outcome measurements and statistical analysis: Our study evaluated the differences in mycobiome among patients with bladder cancer, versus matched controls. Our secondary analysis evaluated compositional differences in the gut as a function of response status with neoadjuvant chemotherapy. Data demultiplexing and classification were performed using the QIIME v.1.1.1.1 platform. The Ion Torrent-generated fungal ITS sequence data were processed using QIIME (v.1.9.1), and the reads were demultiplexed, quality filtered, and clustered into operation taxonomic units using default parameters. Alpha and beta diversity were computed and plotted in Phyloseq, principal coordinate analysis was performed on Bray-Curtis dissimilarity indices, and a one-way permutational multivariate analysis of variance was used to test for significant differences between cohorts. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was applied to infer functional categories associated with taxonomic composition. Results and limitations: We found distinctive mycobiome differences between control group (n = 32) and bladder cancer (n = 29) gut flora, and identified an increasing abundance of Tremellales, Hypocreales, and Dothideales. Significant differences in alpha and beta diversity were present between the groups (control vs bladder; p = 0.002), noting distinct compositions within each cohort. A subgroup analysis by sex and neoadjuvant chemotherapy status did not show any further differences in mycobiome composition and diversity. Our results indicate that the gut mycobiome may modulate tumor response to preoperative chemotherapy in bladder cancer patients. We propose that patients with a "favorable" mycobiome composition (eg, high diversity, and low abundance of Agaricomycetes and Saccharomycetes) may have enhanced systemic immune response to chemotherapy through antigen presentation. Conclusions: Our study is the first to characterize the enteric mycobiome in patients with bladder cancer and describe complex ecological network alterations, indicating complex bacteria-fungi interactions, particularly highlighted among patients with complete neoadjuvant chemotherapy response. Patient summary: Our study has demonstrated that the composition of stool mycobiome (fungal inhabitants of the gastrointestinal tract) in patients with bladder cancer is different from that in noncancer individuals. Furthermore, when evaluating how patients respond to chemotherapy given prior to their surgery, our study noted significant differences between patients who responded and those who did not.