Final Results from a Prospective Randomized Pilot Trial of Stereotactic Body Radiation Therapy vs. Radiofrequency Ablation for the Management of Small Renal Masses (RADSTER)

PURPOSE/OBJECTIVE(S)

The benefits of stereotactic body radiation therapy (SBRT) as a primary treatment modality for small renal masses (SRMs) ≤4cm are unclear. Our objective was to evaluate both SBRT and radiofrequency ablation (RFA) for SRMs to determine the utility of a future Phase III randomized controlled trial (RCT).

MATERIALS/METHODS

Patients with SRMs who declined active surveillance, surgery or were deemed inoperable were recruited at a single tertiary academic center. After meeting inclusion/exclusion criteria, participants were assigned 1:1 to SBRT or RFA, with crossover allowed if technical or patient factors precluded either treatment. SBRT included an initial simulation and a single delivered fraction of 25 Gy to the planning target volume. RFA was conducted percutaneously with 2 cycles of up to 8 minutes each upon reaching target temperature. Renal protocol imaging (CT or MRI) was completed q3 months (up to 1 year) post-procedure. Diagnostic and 1-year renal biopsies were also required. The objective of this trial was feasibility of randomization, with the aim of recruiting 24 patients based on this assumption.

RESULTS

From January 2020 to June 2021, 33 patients were screened, with 24 recruited and initially randomized (SBRT = 12; RFA = 12). Median age was 67 years (53-85) and 17/24 were male. Seventeen patients had clear cell renal cell carcinoma (RCC), 6 had papillary RCC, and 1 had chromophobe RCC. Following randomization, a total of 14 patients had SBRT, 7 had RFA, and 3 declined treatments. Crossover mainly occurred from RFA to SBRT due to technical inability to perform RFA. One grade 2 acute pain flare occurred in the SBRT group (none in the RFA group). No late toxicity up to 1 year was reported in either group. At 1 year, no radiographic local failure (RECIST) was observed, although RFA patients were more likely to have loss of arterial enhancement (83.3% vs 23%, p = 0.041). Mean reduction of estimated glomerular filtration rate was similar at 1 year (RFA -3 mL/min, SBRT -5.3 mL/min, p = 0.7). Biopsies were performed in 20/24 patients at 1 year, on per-protocol analysis 7/7 (100%) of RFA patients had no evidence of residual RCC, whereas with SBRT 4/13 (31%) patients had no evidence of residual RCC, 2/13 (15%) had scant/minimal residual disease, and 7/13 (54%) had evidence of RCC. No patients developed distant failure or death from RCC during follow-up.

CONCLUSION

Recruitment, randomization and follow-up of patients with SRMs was feasible in this study. More patients received SBRT compared to RFA, highlighting the need for thorough multidisciplinary evaluation prior to randomization. Both treatments have excellent safety profiles, with RFA demonstrating initial higher rates of pathological/radiologic response, however long-term follow-up is required. This trial supports the need for a large scale RCT with appropriate radiographic and pathological endpoints built in.

Ureteral Wall Thickness Is an Effective Predictor of Ureteral Stone Impaction and Management Outcomes: A Systematic Review and Meta-analysis

PURPOSE

Ureteral stone impaction is associated with unfavorable endourological outcomes; however, reliable predictors of stone impaction are limited. We aimed to assess the performance of ureteral wall thickness on noncontrast computed tomography as a predictor of ureteral stone impaction and failure rates of spontaneous stone passage, shock wave lithotripsy, and retrograde guidewire and stent passage.

MATERIALS AND METHODS

This study was completed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. A search was conducted in April 2022 for all adult, human, and English language studies investigating ureteral wall thickness using PROSPERO, OVID Medline, OVID EMBASE, Wiley Cochrane Library, Proquest Dissertations & Theses Global, and SCOPUS. A systematic review and meta-analysis using random effects model was conducted. Risk of bias was assessed using the MINORS (Methodological Index for Non-randomized Studies) score.

RESULTS

Fourteen studies with a pooled population of 2,987 patients were included for quantitative analysis, and 34 studies were included in our qualitative review. Meta-analysis findings suggest that a thinner ureteral wall thickness is associated with more favorable subgroup stone outcomes. Thinner ureteral wall thickness suggests a lack of stone impaction and was associated with improved rates of spontaneous stone passage, successful retrograde guidewire and stent placement, and improved shock wave lithotripsy outcomes. Studies lack a standardized ureteral wall thickness measurement protocol.

CONCLUSIONS

Ureteral wall thickness is a noninvasive measure that predicts ureteral stone impaction, and thin measurements are predictive of successful outcomes. Variability in measurement methods confirms that a standardized ureteral wall thickness protocol is needed, and the clinical utility of ureteral wall thickness is yet to be determined.

Minimizing the learning curve for robotic-assisted radical cystectomy A single-surgeon, retrospective, cohort study

INTRODUCTION

Studies published to date have suggested non-inferiority of robotic-assisted radical cystectomy (RARC) compared to open radical cystectomy (ORC), while few centers in Canada have adopted this approach. Though multifactorial, the learning curve and operative time are often discussed barriers. Herein, we present outcomes from the largest Canadian cohort of RARC performed to date.

METHODS

We conducted a retrospective chart review of all patients undergoing RARC by a single surgeon with greater than 1500 robot-assisted radical prostatectomy (RARP) experience at our institution from May 2020 to December 2021. Clinicopathological, intraoperative, and postoperative data, as well as complications in the first 90 days, were collected. Regression analysis was used to determine the relationship between case volume and operative time/lymph node yield.

RESULTS

A total of 31 patients underwent RARC during the study period, 26 of which were male. The median length of stay was six days (Q1-Q3 5-10), while days alive and out of hospital at 90 days were 83 days (Q1-Q3 80-85). Soft tissue margins were positive in 9.6% (3/31) of patients. Median lymph node yield was 17.0 lymph nodes (Q1-Q3 11-23). Median operative time was 241 minutes (Q1-Q3 228-252) in the ileal conduit group and 320 minutes (Q1-Q3 302-337) in the neobladder group. We observed four Clavien-Dindo grade >3 complications. The 90-day readmission rate and mortality rate were 17.2% (5) and 0% (0), respectively. There was no correlation between case volume and any outcome variables.

CONCLUSIONS

Previous high-volume experience performing RARP reduces the learning curve for performing RARC, with similar short-term outcomes to high-volume centers.

Comparison of patients with renal cell carcinoma in adjuvant therapy trials to a real-world population

PURPOSE

To compare characteristics and outcomes of patients included versus those not in adjuvant therapy trials post complete resection of renal cell carcinoma (RCC).

METHODS

Adult patients following complete resection for clear cell RCC between January 1, 2011, and March 31, 2021, were included. Patients had intermediate high, high risk nonmetastatic disease (modified UCLA Integrated Staging System) or fully resected metastatic (M1) disease as per the inclusion criteria of adjuvant studies. Demographic, clinical, and outcomes between trial and nontrial patients were compared.

RESULTS

Of 1,459 eligible patients, 63 (4.3%) participated in an adjuvant trial. Disease characteristics were similar between groups. Trial patients were younger (mean age 58.1 vs. 63.6 years; P < 0.0001) and had lower Charlson Comorbidity Index scores (mean 4.2 vs. 4.9; P = 0.009). Unadjusted disease-free survival (DFS) at 5 years for trial patients was 48.6% and 39.2% for nontrial patients (HR 0.71, 0.48-1.05, P = 0.08). Median DFS was higher for trial patients in comparison to nontrial patients (4.4 years, IQR 1.7- not reached; vs. 3.0 years, IQR 0.8-8.6; P = 0.08). Cancer specific survival (CSS) at 5 years for trial patients was 85.2% in comparison to 78.6% for nontrial patients (HR 0.45, 0.22-0.92, P = 0.03). Unadjusted estimated overall survival (OS) at 5 years was 80.8% for trial patients and 74.8% (HR 0.42, 0.18-0.94; P = 0.04) for nontrial patients.

CONCLUSIONS

Patients in adjuvant trials were younger and healthier with longer CSS and OS in comparison to those not included in adjuvant trials. These findings may have implications when we generalize trial results to real world patients.

First Canadian experience with same-day discharge after robot-assisted radical prostatectomy

INTRODUCTION

We aimed to evaluate the feasibility and safety of implementing a sameday discharge (SD ) protocol for robot-assisted radical prostatectomy (RARP) and pelvic lymph node dissection.

METHODS

We performed a prospective cohort study including all consecutive eligible patients undergoing RARP in 2021 following initiation of SDD RARP protocol in April. Baseline characteristics were compared using t-tests, Mann-Whitney U tests, and odds ratios (OR ) calculated using multiple logistic regression to assess for predictors of SD success.

RESULTS

A total of 117 patients underwent RARP in 2021 following initiation of the SDD protocol. Fifty-seven patients were initiated on the SD pathway and 60 patients underwent surgery as an inpatient (IP-RARP). Of those on the SD pathway (SD-RARP), 33 (58%) were successfully discharged the same day of surgery, while 24 (42%) failed SD . Baseline demographics were well-balanced between cohorts. Case order, increased patient age, and distance travelled to the hospital were factors associated with selection of patients for the IP-RARP protocol. In total, 12 SD and 12 IP patients presented to the emergency department (p=1.0), and none within 24 hours of discharge. There were no hospital admissions in the SD cohort, with four readmissions in the IP cohort (p=0.1). Multiple logistic regression revealed that case order (first case) was the only predictive factor for SD success (OR 4.08, 95% confidence interval 1.59-11.62, p=0.005).

CONCLUSIONS

Implementation of an SD pathway following RARP is feasible, with no increase in rates of complications, unscheduled visits, or readmissions.

A Comparison of Percutaneous Ablation Therapy to Partial Nephrectomy for cT1a Renal Cancers: Results from the Canadian Kidney Cancer Information System

PURPOSE

Percutaneous ablation therapy (AT) and partial nephrectomy (PN) are successful management strategies for T1a renal cancer. Our objective was to compare AT to PN with respect to recurrence-free survival (RFS) and overall survival (OS).

MATERIALS AND METHODS

Patients post-PN or -AT for cT1aN0M0 renal cancer from 2011 to 2021 were identified from the national Canadian Kidney Cancer information system. Inverse probability of treatment weighting (IPTW) using propensity score (PS) was used. The primary outcomes, RFS and OS, were compared using Kaplan-Meier log-rank test analyses and Cox proportional hazard regression models.

RESULTS

A total of 275 patients underwent AT and 2,001 underwent PN, with a median followup of 2.0 years (IQR 0.6-4.1). Covariates were well balanced between the AT and PN cohorts following PS matching. Two-year RFS following IPTW PS analysis for patients undergoing AT and PN was 88.1% and 97.4% (p <0.0001), respectively, while 2-year OS was 97.4% and 99.0% (p=0.7), respectively. Five-year RFS following IPTW PS analysis for patients undergoing AT and PN was 86.0% and 95.1%, respectively (p=0.003), while 5-year OS was 94.2% and 95.1%, respectively (p=0.9). Following IPTW PS analysis, treatment modality (PN vs AT) was a predictor of disease recurrence (HR 0.36, p=0.003) but not for OS (HR 0.96, p=0.9).

CONCLUSIONS

With short followup, PN offers better RFS than AT, although no significant difference in OS was detected following PS adjustments. Both modalities can be offered to appropriately selected patients while we await prospective randomized data.

Successful Same-Day Discharge for Robot-Assisted Radical Prostatectomy: A Systematic Review and Meta-Analysis

INTRODUCTION

Same-day discharge (SDD) following robot-assisted radical prostatectomy (RARP) is emerging as the standard of care. We conducted a systematic review and meta-analysis to evaluate the differences in perioperative characteristics, complication/readmissions rates and satisfaction/cost data between inpatient (IP) RARP and SDD RARP.

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was prospectively registered with PROSPERO (CRD42021258848). A comprehensive search of PubMed®, Embase®, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov and conference abstract publications was performed. A leave-one-out sensitivity analysis was performed to control for heterogeneity and risk of bias.

RESULTS

A total of 14 studies were included with a pooled population of 3,795 patients, including 2,348 (61.9%) IP RARPs and 1,447 (38.1%) SDD RARPs. SDD pathways varied, though many commonalities were present in patient selection, perioperative recommendations and postoperative management. When compared to IP RARP, SDD RARP had no differences in ≥grade 3 Clavien-Dindo complications (RR: 0.4, 95% CI 0.2, 1.1, p=0.07), 90-day readmission rates (RR: 0.6, 95% CI 0.3, 1.1, p=0.10) or unscheduled emergency department visits (RR: 1.0, 95% CI 0.3, 3.1, p=0.97). Cost savings per patient ranged between $367 and $2,109, and overall satisfaction was high at 87.5%-100%.

CONCLUSIONS

SDD following RARP is both feasible and safe, while potentially offering health care cost savings with high patient satisfaction rates. Data from this study will inform the uptake and development of future SDD pathways in contemporary urological care such that it may be offered to a broader patient population.

A prospective randomized parallel-controlled pilot trial of stereotactic body radiation therapy versus radiofrequency ablation for the management of small renal masses

363

Background: The potential of ablative technologies as an alternative to surgery for the treatment of small renal masses (SRMs) ≤4cm is unclear. Our objective was to evaluate the feasibility and toxicity of stereotactic body radiation therapy (SBRT) and radiofrequency ablation (RFA) for SRMs in a prospective randomized pilot trial. Methods: Patients scheduled for renal cell carcinoma (RCC) treatment at a single academic center were approached for the pilot trial, with the aim of recruiting 24 patients. Participants were assigned 1:1 to SBRT or RFA. Imaging (CT or MRI) using a renal tumor protocol is completed at 3, 6, 9, and 12 months post-procedure. Biopsies were completed prior to the procedure and at 12 months. Multiple clinical parameters were collected. Follow-up visits will occur at 6 month intervals following the trial up to 5 years. SBRT included an initial simulation session and a single image-guided treatment session with a prescribed dose of 25 Gy. RFA was conducted by either percutaneous or laparoscopic access with 2 cycles of 8 minutes duration each upon reaching target temperature. Results: Beginning in December 2019, 24 patients were recruited and randomized (SBRT = 11; RFA = 13). Eleven had SBRT, 8 RFA, 3 have not yet had treatment, and 2 became ineligible. Median age for all patients was 67 (53,85) and 17 were male. A total of 17 patients had clear cell RCC, 6 had papillary RCC (type 1), and 1 had chromophobe RCC. All patients had T1a disease. Mean procedure length (minutes) for SBRT and RFA was 15.5±7.4 and 10.5±3.9, respectively. Two patients (both SBRT) had a 12-month biopsy showing no evidence of recurrence or metastases, while two patients (1 RFA, 1 SBRT) had a 9-month CT showing no recurrence. Data are pending for the remaining patients. An early grade 2 flare-up occurred in one SBRT patient. Conclusions: Recruitment and randomization of patients with SRMs in a SBRT vs. RFA prospective trial is feasible on a timeline that allows for regular follow-up and imaging. To date, both treatment modalities have been shown to have excellent short-term safety profiles.

Successful same-day discharge for robot-assisted radical prostatectomy: A systematic review and meta-analysis

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Background: In the current era of enhanced recovery after surgery (ERAS), same day discharge (SDD) following robot-assisted radical prostatectomy (RARP) is emerging as the standard of care. In order to implement a safe and efficient SDD pathway, it is imperative to appropriately select candidates and have established discharge criteria. We conducted a systematic review and meta-analysis to summarize published pathways, as well as to evaluate the differences in peri-operative characteristics, complication/readmissions rates, and satisfaction/cost data, between in-patient (IP) RARP versus SDD-RARP. Methods: This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was prospectively registered with PROSPERO (CRD42021258848). A comprehensive search of PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, Google Scholar, and conference abstract publications was performed comparing outcomes between IP-RARP and SDD-RARP. A leave-one-out sensitivity analyses was performed to control for heterogeneity and risk of bias. Results: A total of 14 studies (eight prospective and six retrospective cohort studies) were included with a pooled population of 3795 patients, including 2348 (61.9%) IP-RARPs and 1447 (38.1%) SDD-RARPs. SDD pathways varied, though many commonalities were present in patient selection (minimal comorbidities and lived close to the hospital [≤ 50-150 km]), peri-operative recommendations (judicious intra-operative intravenous fluids and short-acting narcotics), and post-operative management (immediate ambulation and diet, and non-narcotic analgesia). When compared to IP-RARP, SDD-RARP had no differences in ≥ Grade 3 Clavien–Dindo complications (RR: 0.4, 95% CI 0.2, 1.1, p = 0.07), 90-day readmission rates (RR: 0.6, 95% CI 0.3, 1.1, p = 0.10), or unscheduled ED visits (RR: 1.0, 95% CI 0.3, 3.1, p = 0.97). Cost savings per patient ranged between $367-2109 (USD), and overall satisfaction was high between 87.5-100%. Conclusions: Same day discharge following RARP is both feasible and safe, with comparable complication and readmission rates to IP-RARP. Additionally, SDD offers healthcare cost-savings with high patient satisfaction rates. Data from this study will further inform the uptake and development of future SDD pathways in contemporary urological care such that it may be offered to a broader patient population.

The success of fecal microbial transplantation in Clostridium difficile infection correlates with bacteriophage relative abundance in the donor: a retrospective cohort study

Background: Fecal microbial transplantation (FMT) is used in the treatment of relapsing Clostridium difficile infection (rCDI). Failure rate for FMT is as high as 10% but the mechanisms contributing to a failed FMT are not understood. We utilized metagenomic data to identify the role of bacteria and bacteriophages on FMT success.Results: Subjects with rCDI (n = 19) received FMT from volunteer donors (n = 7) via colonoscopy. Twelve patients fully recovered after a single FMT, while seven patients required a subsequent FMT. DNA was extracted from patient and donor stool samples for shotgun metagenomic analysis. Metagenomics libraries were analyzed focusing on bacterial taxonomy and bacteriophage sequences. Gammaproteobacteria were dominant in rCDI patients prior to FMT largely due to elevated levels of Klebsiella and Escherichia. A successful FMT led to increased levels of Clostridia and Bacteroidia and a reduction in Gammaproteobacteria. In contrast, a failed FMT led to no significant changes in bacterial composition. Bacteriophages were classified during whole metagenomic analysis of each sample and were markedly different between rCDI patients, donors, and a healthy control cohort (n = 96). Bacteriophage sequence reads were increased in CDI patients compared with donors and healthy controls. Successful FMT donors had higher bacteriophage α-diversity and lower relative abundance compared to the donors of a failed initial FMT.Conclusions: In this retrospective analysis, FMTs with increased bacteriophage α-diversity were more likely to successfully treat rCDI. In addition, the relative number of bacteriophage reads was lower in donations leading to a successful FMT. These results suggest that bacteriophage abundance may have some role in determining the relative success of FMT.

Fecal microbial transplantation as a therapeutic option in patients colonized with antibiotic resistant organisms

Despite increasing interest in fecal microbiota transplantation (FMT), its full therapeutic potential has yet to be determined. Since its increase in popularity, FMT has been shown to be highly effective in the treatment of both Clostridium difficile infection (CDI) and its recurrent form. Interest in FMT now expands well beyond the treatment of CDI to other processes with known associations to the microbiota such as antibiotic resistant infections, inflammatory bowel disease (IBD), hepatic encephalopathy, neuropsychiatric disorders, and metabolic disease. The rampant use and misuse of antibiotics in both medicine and agriculture has resulted in an increase in antibiotic resistant organisms which pose a significant risk to human health. The purpose of this commentary is to address the general issue of antibiotic resistance in the human microbiota and the restorative potential of FMT in this area.

Fecal Microbial Transplants Reduce Antibiotic-resistant Genes in Patients With Recurrent Clostridium difficile Infection

Patients with recurrent C. difficile infection harbor large numbers of microbes with antibiotic resistance genes. Fecal microbial transplantation eradicates pathogenic organisms and eliminates antibiotic-resistance genes suggesting this may be a viable treatment option to eradicate multidrug resistant bacteria from patients.

Background. Recurrent Clostridium difficile infection (RCDI) is associated with repeated antibiotic treatment and the enhanced growth of antibiotic-resistant microbes. This study tested the hypothesis that patients with RCDI would harbor large numbers of antibiotic-resistant microbes and that fecal microbiota transplantation (FMT) would reduce the number of antibiotic-resistant genes.

Methods. In a single center study, patients with RCDI (n = 20) received FMT from universal donors via colonoscopy. Stool samples were collected from donors (n = 3) and patients prior to and following FMT. DNA was extracted and shotgun metagenomics performed. Results as well as assembled libraries from a healthy cohort (n = 87) obtained from the Human Microbiome Project were aligned against the NCBI bacterial taxonomy database and the Comprehensive Antibiotic Resistance Database. Results were corroborated through a DNA microarray containing 354 antibiotic resistance (ABR) genes.

Results. RCDI patients had a greater number and diversity of ABR genes compared with donors and healthy controls. Beta-lactam, multidrug efflux pumps, fluoroquinolone, and antibiotic inactivation ABR genes were increased in RCDI patients, although donors primarily had tetracycline resistance. RCDI patients were dominated by Proteobacteria with Escherichia coli and Klebsiella most prevalent. FMT resulted in a resolution of symptoms that correlated directly with a decreased number and diversity of ABR genes and increased Bacteroidetes and Firmicutes with reduced Proteobacteria. ABR gene profiles were maintained in recipients for up to a year following FMT.

Conclusions. RCDI patients have increased numbers of antibiotic-resistant organisms. FMT is effective in the eradication of pathogenic antibiotic-resistant organisms and elimination of ABR genes.

Anticoagulative effect of nitric oxide inhalation in ARDS

Some studies have suggested that nitric oxide (NO) may cause platelet dysfunction. We present an ARDS patient who need this treatment, with a transient alteration of platelet function and a significant prolongation of bleeding time.