This evidence review focuses on transurethral waterjet ablation of the prostate, also known as Aquablation®, and whether the evidence supporting this procedure provides certainty that it will result in improved health outcomes for the Medicare population. This review examines whether PV size, PSA score, specific imaging for PV measurement, Qmax, and the presence of bladder calculus should limit who receives the transurethral waterjet procedure. In general, health outcomes of interest include patient mortality, morbidity, QOL, and function.
For patients with BPH, transurethral waterjet ablation of the prostate endeavors to improve patient outcomes through an image-guided, robotics-assisted surgical procedure that minimizes adverse effects. Palmetto GBA sought patient-centered outcomes as the underlying justification for undergoing the transurethral waterjet ablation procedure. Therefore, a search for peer-reviewed literature was performed in PubMed to identify key clinical circumstances representing covered indications and limitations for performing the procedure. These included PV size, known or suspected prostate cancer (e.g., PSA >10 ng/mL), specific imaging for PV measurement, Qmax, and the presence of bladder calculus. Several searches were performed on PubMed, Google Scholar, and Google. Keywords and Boolean operators used in conjunction for the search were as follows: aquabeam*[tw] OR aqua beam*[tw] OR aquablation*[tw] OR waterablat*[tw] OR water ablat*[tw], waterjet[tw] OR water jet* AND ablat* AND procept OR prostat*, Transurethral waterjet ablat* OR aquablation AND prostat*, Transrectal ultrasound AND prostate AND MRI AND PV. Beyond industry sponsored studies, only a few peer-reviewed papers have been published addressing the performance of transurethral waterjet ablation of the prostate and/or Aquablation®. Search limitations included studies that were only adult-focused (≥19 years of age), human subject, and English language. The search identified 65 studies which were chosen for in-depth review following the title and abstract appraisal. Of the 65 studies, 35 were included for analysis and 30 were excluded for lack of relevancy. Additionally, 2 FDA 510(k) Premarket Notification Database letters were submitted with the reconsideration request and were reviewed.
Pivotal Studies
Initial clinical experience for transurethral waterjet ablation of the prostate was reported in 2016.10 After FDA clearance in 2017, this technology was further studied with the publication of the WATER (Waterjet Ablation Therapy for Endoscopic Resection of Prostate Tissue) trial, a PHASE III multicenter, international, double-blinded, randomized, non-inferiority study with 181 subjects compared Aquablation® (N=116) to TURP (N=65).11,12 Men 45 to 80-years-old with prostate size 30-80 cc (by transrectal ultrasound [TRUS]), moderate-to-severe LUTS (International Prostate Symptom Score [IPSS] ≥12), and Qmax <15 mL/s were included, and stringent exclusion criteria were applied. Although treatment was performed by an unblinded research team, after randomization a separate blinded team performed all follow-up. The primary endpoint was the change in the IPSS at 6 months; scores decreased by 16.9 points for Aquablation® and by 16.1 points for TURP, respectively (non-inferiority P < 0.001 and superiority P = 0.13). The primary safety endpoint was the proportion of subjects with adverse events, defined as Clavien-Dindo grade 2 or higher or any grade 1 with persistent disability. The 3-month primary safety endpoint rate was lower in the Aquablation® group than in the TURP group (26% vs. 42%; P = 0.015). At 2 years, IPSS score improvement was sustained (ΔIPSS = 14.7 in Aquablation® and 14.9 in TURP [P = 0.83; 95% CI for difference -2.1 to 2.6]), and Qmax improvement was large in both groups (11.2 and 8.6 cc/s for Aquablation® and TURP, respectively [P = 0.19; 95% CI for difference -1.3 to 6.4]).13 These results demonstrated that Aquablation® was as effective, if not more effective, as to the standard TURP procedure. The 2-year reduction in post-void residual volume (PVR) was 57 cc and 70 cc for Aquablation® and TURP, respectively (P = 0.39). PSA decreased significantly in both groups by 1 point (P < 0.01). Re-treatment rates were 4.3% and 1.5% (P = 0.42) in the Aquablation® and TURP groups, respectively. Among the subset of sexually active men without the condition at baseline, anejaculation was less common after Aquablation® (10% vs. 36%; P = 0.0003). When post- Aquablation® cautery was avoided rates of anejaculation were lower (7% vs.16%; P = 0.18), and this resulted in reduced grade 1 persistent events identified in the Aquablation® group. The authors believe that Aquablation® avoids damage to tissues involved in ejaculation through precise, image-based targeting, and robotic execution. The limitations of the study include the risk of performance bias, as surgeons were not blinded, and unknown generalizability to a more heterogeneous US population as it is a single-center study of males ages 50-80 years in New Zealand. The 3-year results were essentially unchanged.4
A 2019 Cochrane Review based on the 1-year Aquablation® trial results found comparable results, with TURP to be of moderate certainty related to the IPSS primary outcome measure. All other metrics were graded from low-certainty to very low-certainty (adverse events, retreatments, erectile function, ejaculatory dysfunction).3 The certainty of studied outcomes was downgraded due to study limitations (performance, reporting, and attrition bias) and imprecision (e.g., confidence intervals that crossed the assumed thresholds of clinically significant differences or few events, or both). For example, both sexual outcome (erectile and ejaculatory function) results were downgraded 2 levels for a combination of imprecision and study limitations (substantial risk of performance and attrition bias). The authors recommended larger, more rigorously conducted, and transparently reported studies comparing Aquablation® to other techniques (laser enucleation, prostatic urethral lift, robotic-assisted simple prostatectomy) for which there is also increasing interest.
In a study by Nguyen et al,6 the authors aimed to determine if the effectiveness of Aquablation® is independent of prostate size by comparing its outcomes in 2 clinical trials. The first trial that was conducted was with men whose prostate was between 30 and 80 mL (WATER I) and the other trial was conducted with men whose prostates were between 80 and 150 mL (WATER II). WATER I trial was a prospective, double-blind, multicenter, international clinical trial comparing the safety and efficacy of Aquablation® and TURP as surgical treatments of LUTS due to BPH in men aged 45 to 80 years with a PV between 30 and 80 mL, as measured by TRUS. Patients were enrolled at 17 centers.12 One hundred sixteen men participated. The WATER II trial was a prospective, multicenter, international clinical trial of Aquablation® for the surgical treatment of LUTS/BPH in men aged 45 to 80 years with a PV between 80 and 150 mL, as measured by TRUS.14 Patients were enrolled at 13 US and 3 Canadian sites. One hundred one men participated. The study’s parameters included patients who completed the IPSS. Patients completed questionnaires such as the Incontinence Severity Index (ISI), the International Index of Erectile Function (IIEF-5), and the Male Sexual Health Questionnaire for Ejaculatory Dysfunction (MSHQ-EjD). Patients received uroflowmetry, PVR measurements, and underwent standard laboratory blood assessments. These questionnaires and measurements were provided at baseline. PVR and lab tests were also required at 1- and 3-months postoperatively. The clinical events committee graded adverse events using the Clavien-Dindo classification and rated their causation as possibly, probably, or definitely related to the study procedure for 3 months after treatment. The inclusion and exclusion criteria were the same for both studies. The inclusion criteria included patients with moderate-to-severe symptoms indicated by a baseline IPSS of ≥12 and a Qmax of <15 mL/s. Exclusion criteria included patients with a BMI (calculated as weight in kilograms divided by height in meters squared) of ≥42 kg/m², a history of prostate or bladder cancer, neurogenic bladder, bladder calculus or clinically significant bladder diverticulum, active infection, treatment for chronic prostatitis, diagnosis of urethral stricture, meatal stenosis or bladder neck contracture, a damaged external urinary sphincter, stress urinary incontinence, PVR >300 mL, or urinary retention. The comparison between the 2 studies revealed the mean operative time for WATER I was 33 minutes and 37 minutes for WATER II. The actual treatment time was 4 minutes (WATER I) and 8 minutes (WATER II). For IPSS, the mean change at 12 months averaged 15.1 for WATER I and 17.1 for WATER II (P = 0.60). Adverse events of Clavien-Dindo grade ≥2 occurred in 19.8% of WATER I patients and 34.7% of WATER II patients (P = 0.47) at 3 months post-operatively.6 The authors concluded that the outcomes and effectiveness of Aquablation® are comparable, and are independent of prostate size, with the expectation that with larger prostates a higher risk of complication is possible.
In the April 2020 publication of WATER II by Desai et al,5 2-year safety and effectiveness data of the Aquablation® procedure in men with symptomatic BPH and large volume prostates (80-150 cc) were evaluated. Enrolled participants averaged a PV of 107 cc, a group typically excluded from undergoing TURP. The evidence supports superior improvements from Aquablation® at mid-term (2 year) follow-up and quality long-term results for the treatment of LUTS related to BPH.
Specialty Society Guidelines and Systematic Reviews
Per recent guidelines from the American Urological Association (AUA), robotic waterjet ablation requires general anesthesia and is not considered to be a minimally invasive surgical treatment (MIST).15 Based on the WATER I study results the AUA found parity between Aquablation® and TURP on IPSS, LUTS, and QOL scores (Quality of Evidence: Moderate). Their recommendation was: “Aquablation® may be offered to patients with LUTS attributed to BPH provided PV >30/<80g; however, patients should be informed that long-term evidence of efficacy and re-treatment rates remains limited”16 (Conditional Recommendation; Evidence Level: Grade C).
Guidelines from the Canadian Urological Association (CUA) published in 2018 also give a “conditional recommendation based on moderate-quality evidence” that Aquablation® may be offered to men “interested in preserving ejaculatory function, with prostates <80 cc, with or without a middle lobe.”17
In 2018, a systematic review from the National Institute for Health and Care Excellence (NICE) was published, based on 6-month WATER I trial results, which concluded the Aquablation® procedure should only be used with “special arrangements,” a defined designation which indicates that there are uncertainties about safety and effectiveness.18
Patient Age
The original studies did not evaluate the use of this procedure in men ≥ the age of 80 years, therefore, safety and efficacy data were lacking in that population. Additional literature was submitted and reviewed that included men ≥80 years of age.
Gilling et al. in a 2022 publication, reported the results of a double-blinded, randomized, and controlled trial conducted at multiple centers with a 5 year follow-up comparing patients that received TURP versus transurethral waterjet ablation.19 One hundred eighty-four men aged 45 to 80 years with LUTS secondary to BPH were studied comparing the safety and efficacy of Aquablation® and TURP for those with moderate-to-severe symptoms as measured by IPSS and Qmax. The primary safety endpoint was the proportion of subjects with adverse events rated by the clinical events committee as possibly, probably, or definitely related to the study procedure. The primary efficacy endpoint was the change in IPSS from baseline to 6 months. Secondary safety endpoints included resection time, total operative time, length of hospital stay, reoperation or reintervention rate, the proportion of sexually active subjects reporting worsening sexual function, and the proportion of subjects with a serious device or procedure-related adverse event. Primary safety endpoints were successfully achieved at 3 months as the Aquablation® study group had a lower event rate than the TURP study group. Procedure-related ejaculatory dysfunction was lower for Aquablation®. The primary efficacy endpoint was successfully achieved at 6 months, where the mean IPSS score decreased from baseline by 16.9 points for Aquablation® and 15.1 points for TURP. The mean difference in change score at 6 months was 1.8 points greater for the Aquablation® study group. At 5 years, IPSS scores improved by 15.1 points in the Aquablation® study group and 13.2 points in the TURP study group (P = 0.28). For men with larger prostates (≥ 50 mL) IPSS reduction was 3.5 points greater across all follow up visits in the Aquablation® study group compared to the TURP study group (P = 0.01). Improvement in peak urinary flow rate was 125% and 89% compared to baseline for Aquablation® and TURP, respectively. The risk of patients needing secondary BPH therapy, defined as needing BPH medication or surgical intervention, up to 5 years due to recurrent LUTS was 51% less in the Aquablation® study arm compared to the TURP study arm. The authors of the study observed that the Aquablation® procedure improved BPH-related urinary symptoms compared to the referenced standard treatment (TURP) over 5 years.19 Study limitations included lower than expected follow-up percentages at 4- and 5-years which the authors attributed to the COVID-19 pandemic, non-US based study facilitation, and author identified conflict of interests.
An additional retrospective observational study published in 2020,20 documented the use of Aquablation® at a single center in the US. This study was comprised of 55 men with a mean PV of 100 cc (range 27-252 cc) and a prominent obstructing middle lobe in 85% of them. Baseline assessment and a follow-up assessment at 3 months were completed. A substantial improvement of 80% (17 points) was seen in BPH symptoms scores. Qmax, measured by flowmetry, improved by 182% (14 mL/s). IPSS QOL scores improved by 3.3 points.20 The age of male subjects included those >80 years of age (range 50 to 84-years-old), but the actual number of subjects over 80 years was not reported. Limitations for this study included a small sample size, the observational study design, and a short follow-up period.
Prostate Volume
Four publications were identified which addressed the use of Aquablation® for prostates over 150 cc in size.20,22,23,66 A retrospective observational study published in 2020,20 documented the use of Aquablation® at a single center in the US. This study was comprised of 55 men with a mean PV of 100 cc (range 27-252 cc) and a prominent obstructing middle lobe in 85% of them. Baseline assessment and a follow-up assessment at 3 months were completed. A substantial improvement of 80% (17 points) was seen in BPH symptoms scores. Qmax, measured by flowmetry, improved by 182% (14 mL/s). IPSS QOL improved by 3.3 points.20 The range of prostate sizes did include prostates over 150 cc, but the actual number of subjects over 150 cc was not reported. Limitations for this study included a small sample size, the observational study design, and a short follow-up period.
An additional retrospective observational study by Helfand et al. investigated the use of Aquablation® in 251 men with LUTS secondary to BPH who have very large prostates (>150 mL).22 Aquablation® resulted in an improved Qmax with an increase from 7 mL/s to 19 mL/s (P < 0.001) and an improved IPSS score from 19 to 7 for men with prostates >150 mL. No significant differences were found in terms of IPSS, QOL, or uroflowmetry based on PV group. Limitations of this study included the retrospective nature of the study, the use of historic data in controlled clinical trials to create comparison groups, and a short follow-up. The largest limitation of the study, however, was that while the study was aimed at examining prostates over 150 mL, only 34 (14%) of the study participants had prostates >150 mL in size, preventing the overall results from being generalized to the population at which the LCD limitation is addressed piece of reviewed literature was an editorial companion piece published in 2022 by Helfand et al. highlighting physician’s real-world experience using Aquablation® in men with LUTS, secondary to BPH, who have prostates >150 mL.23 This editorial references the data used in the above-described study by Helfand et al., 2021. The publication explains that the surgical options for men with prostates >150 mL are limited. Currently, the options include simple prostatectomy, anatomic enucleation of the prostate, and waterjet ablation. For waterjet ablation in men with very large prostates, there are some additional surgical steps not found in surgeries for those with smaller prostates. While the procedure for very large prostates begins the same way as average sized prostates, because of the length and depth of the prostate as well as the size of the handpiece for operating, multiple passes of the waterjet are required during the operation. Likewise, if the prostate length is greater than 7 cm, the scope tip will not reach the internal sphincter so additional planning is required in transverse view. Due to the multiple planning periods, adjustments of the handpiece, and swipes of the beam, Aquablation® in very large prostates does have additional procedure-related risks such as a greater chance for bleeding. Limitations of this article include the small sample size, high risk of bias (RoB) due to the observational real-world evidence referenced, and the paper's editorial nature.
A more recent study by Ringler et al., 2024 was a retrospective cohort study (retrospective and observational). Enrollment included 170 patients, allocated in a 1:4 ratio with fewer than 20% of patients falling into the > 150 mL group. Outcomes essentially only involved a sample of 33 patients to represent this patient population but overall were similar to those of Helfand et al. for the > 150 mL group. The authors mention the sample size as a study limitation and conclude their discussion with the following: “This study is, therefore, among the first to demonstrate the safety and efficacy of Aquablation® in PV greater than 150 mL, albeit with greater need for follow-up and retreatment compared to PV <150 mL.” Another limitation is the single center retrospective observational design of the study.
PSA Score
Peer-reviewed studies on the usefulness of the PSA score in evaluating patients for transurethral waterjet ablation of the prostate were sought and analyzed. One study addressed the oncological outcomes for patients undergoing TURP with varying PSA scores.8 Hilscher and colleagues (2022)8 performed a pooled analysis of 63,781 men who underwent a TURP to analyze the risk of prostate cancer incidence and mortality following a benign histological assessment. The study found that 10-year risks of any prostate cancer and prostate cancer with a Gleason score ≥ 3+4, and the 15-year risk of prostate cancer death, showed a clear relationship on a scatterplot with increasing PSA. The 15 year cumulative incidence of prostate cancer-specific death after benign TURP was 1.4% (95% confidence interval [CI], 1.3%–1.6%) for all men and 0.8% (95% CI,.6%–1.1%) for men with PSA levels <10 ng/mL.8 It was concluded that there was little to no risk of adverse oncological outcomes for patients with PSA below 10 ng/mL at the time of TURP, but the authors did note that more extensive follow-up may be needed for those with higher PSA levels. The NCCN 2024 Prostate Cancer guidelines were also appraised for their guidance for patients with varying levels of prostate cancer and PSA scores.25 Management of suspected prostate cancer is dependent on a multi-factorial risk profile.
A 2025 prospective study by Teoh et al. investigated the impact of Aquablation® on circulating tumor cells (CTCs) in men with localized prostate cancer.65 Subjects with biopsy-positive mpMRI visible lesions (PIRADS ≥3) who were candidates for active surveillance and desired Aquablation® for LUTS were included. The study group included 5 subjects with a mean age of 63.4 ± 6.4 years and had baseline PSA of 8.9 ± 1.7 ng/mL. While a transient spike in CTCs was observed immediately after the procedure, it was short-lived and did not raise oncological concerns.
Qmax and Voided Volume
Peer-reviewed literature focused on providing information on the safety and effectiveness of performing transurethral waterjet ablation of the prostate in patients with Qmax ≤15 mL/s (voided volume greater than 125 cc) was sought and analyzed. Four publications were identified which addressed the safety of performing transurethral waterjet ablation of the prostate in patients with retention abilities and showed the effectiveness of the procedure on Qmax. Additionally, the WATER II trial, which has been mentioned in previous sections, included cohorts of catheter-dependent patients who could not pass meaningful amounts of urine, and therefore, could not undergo a flow rate test that requires 125 cc of volume voided. This cohort of catheter-dependent patients,24 demonstrated benefit from undergoing the Aquablation® procedure. AUA guidelines on the Management of LUTS Attributed to BPH, published in 2021, addressed the treatment of patients in urinary retention.15 The guideline states that indications for surgery include “a desire by the patient to avoid taking a daily medication, failure of medical therapy to sufficiently ameliorate bothersome LUTS, intolerable pharmaceutical side effects, and/or the following conditions resulting from BPH and for which medical therapy is insufficient: acute and/or chronic renal insufficiency, refractory urinary retention, recurrent urinary tract infections (UTIs), recurrent bladder stones (BS), and recalcitrant gross hematuria.”15 The guideline identifies Robotic Waterjet Treatment (e.g., Aquablation®) as a treatment option for patients with LUTS/BPH provided that the PV ranges between 30-80 cc.15
Additional peer-reviewed literature has demonstrated that Aquablation® is clinically effective and safe in patients with catheter-dependent urinary retention. Burton et al. compared outcomes of Aquablation® in men with acute and chronic urinary retention.26 This retrospective study of 113 men (69 not in retention, 28 with acute retention and 16 with chronic retention) found no difference in utilization of postoperative prostate medications, complications, IPSS, or uroflowmetry between men with acute, chronic, or no retention. There was no significant difference for men using intermittent catheterization as compared to those with an indwelling catheter prior to surgery in relation to the ability to return to spontaneous voiding faster (P = 0.31). The study found that 98% of participants achieved spontaneous voiding after Aquablation® regardless of preoperative urodynamic status. Limitations of this study included small sample sizes for acute and chronic patients, preoperative urodynamics not routinely obtained for all patients, and the study’s retrospective nature.
A prospective observational study addressed a cohort of 60 men with significant BPH who underwent Aquablation® at a single ambulatory surgery center.27 Results showed significant improvements in urinary flow rates and significant reductions in IPSS scores at 1 month post-operatively. The occurrence of pain post Aquablation® procedure was infrequent and the incidence of postoperative complications, including urinary retention, was infrequent and in alignment with previously published outcomes. The mean 1-month Qmax increased to 26 mL/s and the mean PVR volume decreased to 39 mL. The authors noted several limitations that include a short follow-up time, a small sample size, performance in a single center study, and an accompanying selection bias.
Finally, a prospective observational study by Labban et al. published in 2021,28 assessed 59 consecutive patients who underwent Aquablation® at a tertiary care center. The study population included 14 patients in urinary retention. At the 3-month follow-up, significant drops in PSA score, prostate size, and IPSS (P < 0.001 for all) were observed. PVR volume was reduced significantly –186 ± 82 mL (P = 0.01). A sub-analysis among patients with retention at baseline revealed a similar operative time (P = 0.38), length of catheterization (P = 0.53), and length of hospital stay (P = 0.94) when compared to patients not in urinary retention. The study had limitations which included a small sample size and the lack of a control group. Despite these limitations, the results of this study echo the findings of other studies that confirmed improved voiding parameters and decreased LUTS.
Bladder Calculus
Peer-reviewed literature on the safety and effectiveness of performing BPH surgery in patients who may have BS or need both BPH surgery and BS removal procedures were analyzed. No studies were identified using waterjet ablation of the prostate in setting of bladder calculus. A retrospective study comparing surgery for both BPH and BS,29 and an updated AUA guideline paper were identified.16 Both articles addressed the safety and efficacy of performing BPH surgery in patients who may have bladder calculus. Chapelle et al. retrospectively reviewed 179 men over the age of 50 years who underwent BS removal, with or without concomitant BPH surgery.29 The outcome criteria used in this study were early postoperative complications, stone recurrence, subsequent surgery for BS or BPH, and late surgical complications. An aggregate score ranging from 0 to 4 was calculated by combining the 4 criteria, with 4 representing successes in all categories. One hundred seven patients were in the concomitant surgical treatment (CST) group and 72 patients in the BS removal alone (SRA) group. The patients who underwent CST had a significantly lower rate of BS recurrence (12% vs. 39%; P = 0.001) and underwent fewer consequent surgeries (P <0 .001). There was an observed difference in composite score between the CST and SRA groups, but the difference was not significant (3.07 vs. 2.72, P = 0.08). Fifty-one percent of patients in the CST group had early complications (e.g., acute urinary retention with and without infection, bladder clots, urinary urgency, ICU admission, death) compared to 35% of the SRA group (P = 0.17). After 1-month, late complications included urinary incontinence (15% for CST and 6% for SRA, P = 0.092), and de novo urethral stenosis (4% CST and 7% SRA group, P = 0.491). In this study a significant number of patients (44%) in the SRA group still required subsequent stone removal or BPH surgery. Based on this study, the combined surgical approach for the removal of prostate and bladder calculi may result in greater harm than the anticipated clinical benefits. Additionally, this approach does not consistently eliminate the need for subsequent procedures. The authors conclude that there is insufficient support for the routine use of a combined surgical approach for treating both BPH and BS at the time of initial management and that further larger studies of a prospective nature are needed.
In 2023, Sandhu et al. published an amendment to the AUA guideline for “Management of Lower Urinary Tract Symptoms Attributed to Benign Prostatic Hyperplasia (BPH).”16 The purpose of this amendment was to add additional evidence-based management guidance of male LUTS secondary to BPH. The AUA guidelines provide a single surgical recommendation on BS which states that, “Surgery is recommended for patients who have renal insufficiency secondary to BPH, refractory urinary retention secondary to BPH, recurrent urinary tract infections (UTIs), recurrent bladder stones or gross hematuria due to BPH, and/or with LUTS/BPH refractory to or unwilling to use other therapies.”16 Surgery is recommended for BS patients only for whom medical therapy is insufficient. Multiple surgical options were identified in the guideline (e.g., MIST, prostatectomy, and transurethral surgery), however, there was no recommendation for the use of transurethral waterjet ablation (e.g., Aquablation®) in this clinical scenario.
Prostate Volume Measurement
PubMed and Google Scholar were searched for peer-reviewed, evidence-based literature providing information on the analytic and clinical validity and clinical utility of TRUS and Magnetic Resonance Imaging (MRI). Keywords used in the search were transrectal ultrasound and prostate and MRI and prostate volume.
A total of 2 publications, observational studies of retrospective nature, addressed the analytical validity of MRI and TRUS for PV measurement.30,31 Studies excluded from analysis included systematic reviews with a low certainty of evidence,32,33 studies focusing on Prostate-Specific Antigen Density (PSAD)34 and studies addressing the clinical utility of MRI-targeted biopsy,35 which is beyond the scope of this LCD.
Bezinque et al. retrospectively reviewed records of 99 patients who underwent radical prostatectomy within 1 year of multiparametric prostate MRI (mpMRI) to determine optimal PV measurement techniques.30 The reference used was manual segmentation by a radiologist (MRI-R3D). MRI based methods were found to be the most reliable, with stronger intra-class correlation coefficients of 0.91 for manual segmentation by a third-year medical student (MRI-S3D) and 0.90 for MRI-ellipsoid formula. Digital rectal examinations (DRE) were the least reliable (0.33). Although TRUS yielded less favorable results (0.71), it remains a useful tool for PV measurement as it is reliable, reasonably accurate, and commonly used when mpMRI is not performed.30
In addition to the retrospective nature of this study, the authors have noted several limitations. These include small sample size, the failure to use surgical specimens as a reference standard, which may have provided more accurate PV measurements, and lack standardization between participating institutions. Therefore, interobserver variation could not be assessed, as a single radiologist performed the reference measurements, and a single urologist determined DRE and TRUS measurements. Other studies have shown low interobserver variability for MRI in PV assessments, thereby minimizing concern for MRI-R3D as the reference standard. The outcomes may have been affected by changes in prostate sizes within 1 year of mpMRI, as well as the absence of computed tomography (CT) segmentation data for PV to compare with other methods. Due to the average younger age of 63 years (range of 59-68) and undergoing radical prostatectomy in the study cohort, results also may not be fully generalizable to the Medicare population, and outcomes may have differed for those older or without prostate cancer.30
Analytical validity was assessed by Weiss et al. in a retrospective comparison of preoperative TRUS versus endorectal MRI (eMRI) in 756 patients diagnosed and treated for localized prostate cancer. A high correlation was found between the 2 methods in estimating PV using the prolate ellipsoid formula. There was a significant correlation for average prostate size measured (R=0.801; P < 0.001), as well as a strong linear relationship. The average difference in measurement in TRUS relative to eMRI was 1.7 mL, showing statistical significance (P < 0.001), without clinical relevance. These conclusions support the use of TRUS for PV measurement in patients with prostatic disease due to its accuracy, reproducibility, and efficacy, despite the superiority of MRI based estimation of prostate size.31
Body Mass Index
The original studies did not define the use of this procedure in men with a BMI ≥ 42 kg/m², resulting in a lack of data supporting its application within this population. Further searches reveal no new evidence of the procedure’s use in men with a BMI ≥ 42 kg/m². Overall, based on the submitted and reviewed literature, there is little to no evidence available to support the inclusion of men with a BMI ≥ 42 kg/m² under covered indications.