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Editorial: How long is long enough for pharmacological thromboprophylaxis in urology?

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Each year, millions of patients who undergo urological surgery incur the risk of deep vein thrombosis and pulmonary embolism, together referred to as venous thromboembolism (VTE), and major bleeding. Because pharmacological prophylaxis decreases the risk of VTE, but increases the risk of bleeding, and because knowledge of the magnitude of these risks remains uncertain, both clinical practice and guideline recommendations vary widely [1]. One of the uncertainties is the recommended duration of pharmacological thromboprophylaxis.

In this issue of the BJUI, Naik et al. [2] provide an up‐to‐date review that summarises the articles that examined extended thromboprophylaxis in patients with cancer who underwent radical prostatectomy (RP), radical cystectomy (RC) or nephrectomy. The outcomes on which they focussed include risks of VTE, bleeding, renal failure and mortality – all potentially influenced by whether or not patients receive extended prophylaxis.

After screening >3500 articles, the authors included 18 studies, none of them randomised controlled trials (RCTs) [2]. They found that VTE risk is highest in open and robot‐assisted RC, and that, based on observational studies, extended thromboprophylaxis significantly reduces the risk of VTE relative to shorter duration prophylaxis. Evidence suggested that robot‐assisted RP, as well as both open and robot‐assisted partial and radical nephrectomies, incur lower VTE risk than RCs or open RP. They did not find studies comparing extended prophylaxis to standard prophylaxis for RPs or nephrectomies [2].

Overall, these findings are consistent with systematic reviews that estimated the procedure‐ and patient risk factor‐specific risks for 20 urological cancer procedures [3]. As these reviews suggested substantial procedure‐specific differences in the VTE risk estimates, the European Association of Urology (EAU) Guidelines provided separate recommendations for each procedure [4]. For urological (as well as gastrointestinal and gynaecological) patients, the National Institute for Health and Care Excellence (NICE) Guidelines suggest to ‘consider extending pharmacological VTE prophylaxis to 28 days postoperatively for people who have had major cancer surgery in the abdomen’ [5]. Because of variation in both bleeding and thrombosis risks across procedures, this advice is appropriate for some procedures and misguided for others. For instance, the procedure‐specific EAU Guidelines recommend extended VTE prophylaxis for open RC but not for robot‐assisted RP without lymphadenectomy [4].

The review by Naik et al. [2] identified the lack of urology‐specific studies comparing the in‐hospital‐only prophylaxis to extended prophylaxis. The few included studies were observational with considerable limitations (e.g. limited adjustment for possible confounders).

A recent update of a Cochrane review compared the impact of extended thromboprophylaxis with low‐molecular‐weight heparin (LMWH) for at least 14 days to in‐hospital‐only prophylaxis in abdominal or pelvic surgery procedures [6]. The authors identified seven RCTs (1728 participants) evaluating extended thromboprophylaxis with LMWH and generated pooled estimates for the incidence of any VTE (symptomatic or asymptomatic) after major abdominal or pelvic surgery of 13.2% in the control group compared with 5.3% in the patients receiving extended out‐of‐hospital LMWH (odds ratio [OR] 0.38, 95% CI 0.26–0.54).

Most events were asymptomatic, although the incidence of symptomatic VTE was also reduced from 1.0% in the in‐hospital‐only group to 0.1% in patients receiving extended thromboprophylaxis (OR 0.30, 95% CI 0.08–1.11). The authors reported no persuasive difference in the incidence of bleeding complications within 3 months of surgery (defined as major or minor bleeding according to the definition provided in the individual studies) between the in‐hospital‐only group (2.8%) and extended LMWH (3.4%) group (OR 1.10, 95% CI 0.67–1.81).

These findings are consistent with our own modelling study that demonstrated an approximately constant hazard of VTE up to 4 weeks after surgery [7]. That study also found that bleeding risk, by contrast, is concentrated in the first 4 days after surgery [7] (Fig.1). Using these findings, the EAU Guidelines suggest for patients in whom pharmacological prophylaxis is appropriate, extended pharmacological prophylaxis for 4 weeks [4]. Consistent with these recommendations, Naik et al. [2] found that 15 studies of 18 included in their review recommended extended prophylaxis.

Fig.1 Proportion of cumulative risk (%) of venous thromboembolism (VTE) and major bleeding by week since surgery during the first 4 postoperative weeks. Reproduced from: Tikkinen et al. [7].

(This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (https://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.)

 

Overall, as shown also by this review [2], the evidence base for urological thromboprophylaxis is limited. Although current evidence supports extended prophylaxis, definitively establishing the optimal duration of thromboprophylaxis will require large‐scale RCTs. Other unanswered key questions include: baseline risks of various procedures, timing of prophylaxis, patient risk stratification, as well as effectiveness of direct oral anticoagulants. In the meanwhile, suggesting extended duration to patients whose risk of VTE is sufficiently high constitutes a reasonable evidence‐based approach to VTE prophylaxis.

by Kari A.O. Tikkinen and Gordon H. Guyatt

 

References

  1. Violette PD, Cartwright R, Briel M, Tikkinen KA, Guyatt GH Guidelines of guidelines: thromboprophylaxis for urological surgery. BJU Int 2016; 118: 351– 8
  2. Naik R, Mandal I, Hampson A et al. The role of extended venous thromboembolism prophylaxis for major urological cancer operations. BJU Int 2019; 124: 935-44
  3. Tikkinen KA, Craigie S, Agarwal A et al. Procedure‐specific risks of thrombosis and bleeding in urological cancer surgery: systematic reviews and meta‐analyses. Eur Urol 2018; 73: 242– 51
  4. Tikkinen KA, Cartwright R, Gould MK et al. EAU Guidelines on Thromboprophylaxis in Urological Surgery, 2017. European Association of Urology, 2018. Accessed November 2019
  5. National Institute for Health and Care Excellence (NICE). Venous Thromboembolism in over 16s: reducing the risk of hospital‐acquired deep vein thrombosis or pulmonary embolism. NICE guideline [NG89]. London: NICE, 2018. Accessed November 2019
  6. Felder S, Rasmussen MS, King R et al. Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery. Cochrane Database Syst Rev 2019; 3: CD004318
  7. Tikkinen KA, Agarwal A, Craigie S et al. Systematic reviews of observational studies of risk of thrombosis and bleeding in urological surgery (ROTBUS): introduction and methodology. Syst Rev 2014; 23: 150. DOI: 10.1186/2046‐4053‐3‐150.

 

Video: Role of extended venous thromboembolism prophylaxis for major urological cancer operations

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The role of extended venous thromboembolism prophylaxis for major urological cancer operations

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Abstract

Objectives

Venous thromboembolism (VTE), consisting of both pulmonary embolism (PE) and deep vein thromboses (DVT), remains a well‐recognised complication of major urological cancer surgery. Several international guidelines recommend extended thromboprophylaxis (ETP) with LMWH, whereby the period of delivery is extended to the post‐discharge period, where the majority of VTE occurs. In this literature review we investigate whether ETP should be indicated for all patients undergoing major urological cancer surgery, as well as procedure specific data that may influence a clinician’s decision.

Methods

We performed a search of six databases (PubMed, Cochrane, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, and British Nursing Index (BNI)) from inception to June 2019, for studies looking at adult patients who received VTE prophylaxis after surgery for a major urological malignancy.

Results

Eighteen studies were analysed. VTE risk is highest in open and robotic Radical Cystectomy (RC) (2.6–11.6%) and ETP demonstrates a significant reduction in risk of VTE, but not a significant difference in Pulmonary Embolism (PE) or mortality. Risk of VTE in open Radical Prostatectomy (RP) (0.8–15.7%) is comparable to RC, but robotic RP (0.2–0.9%), open partial/radical nephrectomy (1.0–4.4%) and robotic partial/radical nephrectomy (0.7–3.9%) were lower risk. It has not been shown that ETP reduces VTE risk specifically for RP or nephrectomy.

Conclusion

The decision to use ETP is a fine balance between variables such as VTE incidence, bleeding risk and perioperative morbidity/mortality. This balance should be assessed for each specific procedure type. While ETP still remains of net benefit for open RP as well as open and robotic RC, the balance is closer for minimally invasive RP as well as radical and partial nephrectomy. Due to a lack of procedure specific evidence for the use of ETP, adherence with national guidelines remains poor. Therefore, we advocate further studies directly comparing ETP vs standard prophylaxis, for specific procedure types, in order to allow clinicians to make a more informed decision in future.

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Visual abstract: The role of extended venous thromboembolism prophylaxis for major urological cancer operations

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Article of the week: Characterising ‘bounce‐back’ readmissions after radical cystectomy

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Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an editorial written by a prominent member of the urology community and a visual abstract prepared by a creative urologist; we invite you to use the comment tools at the bottom of each post to join the conversation. 

If you only have time to read one article this week, it should be this one.

Characterising ‘bounce‐back’ readmissions after radical cystectomy

Peter S. Kirk*, Ted A. Skolarus*†, Bruce L. Jacobs‡, Yongmei Qin*, Benjamin Li*, Michael Sessine*, Xiang Liu§, Kevin Zhu*, Scott M. Gilbert, Brent K. Hollenbeck*, Ken Urish**, Jonathan Helm††, Mariel S. Lavieri§ and Tudor Borza‡‡

*Dow Division of Health Services Research, Department of Urology, University of Michigan Health System, Ann Arbor, MI, USA, †VA Health Services Research and Development, Center for Clinical Management Research, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA, ‡Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA, §Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI, USA, Department of Genitourinary Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA, **Department of Orthopedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA, ††Department of Operations and Decision Technologies, Kelley School of Business, Indiana University, Bloomington, IN, USA, and ‡‡Department of Urology, University of Wisconsin, Madison, WI, USA

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Abstract

Objective

To examine predictors of early readmissions after radical cystectomy (RC). Factors associated with preventable readmissions may be most evident in readmissions that occur within 3 days of discharge, commonly termed ‘bounce‐back’ readmissions, and identifying such factors may inform efforts to reduce surgical readmissions.

Patients and Methods

We utilised the Healthcare Cost and Utilization Project’s State Inpatient Databases to examine 1867 patients undergoing RC in 2009 and 2010, and identified all patients readmitted within 30 days of discharge. We assessed differences between patients experiencing bounce‐back readmission compared to those readmitted 8–30 days after discharge using logistic regression models and also calculated abbreviated LACE scores to assess the utility of common readmissions risk stratification algorithms.

Results

The 30‐day and bounce‐back readmission rates were 28.4% and 5.6%, respectively. Although no patient or index hospitalisation characteristics were significantly associated with bounce‐back readmissions in adjusted analyses, bounce‐back patients did have higher rates of gastrointestinal (14.3% vs 6.7%, P = 0.02) and wound (9.5% vs 3.0%, P < 0.01) diagnoses, as well as increased index and readmission length of stay (5 vs 4 days, P = 0.01). Overall, the median abbreviated LACE score was 7, which fell into the moderate readmission risk category, and no difference was observed between readmitted and non‐readmitted patients.

Conclusion

One in five readmissions after RC occurs within 3 days of initial discharge, probably due to factors present at discharge. However, sociodemographic and clinical factors, as well as traditional readmission risk tools were not predictive of this bounce‐back. Effective strategies to reduce bounce‐back readmission must identify actionable clinical factors prior to discharge.

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Editorial: Threading the cost–outcome needle after radical cystectomy

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I commend Borza et al. [1] on their timely study, which seeks to identify predictors of bounceback (≤3‐day) vs 30‐day readmissions after radical cystectomy. As the authors allude to in their paper, value‐based health reforms being undertaken in the USA seek to improve the quality of care delivery while simultaneously bending the healthcare cost curve [2]. For example, the Hospital Readmission and Reduction Program (HRRP), originally introduced in fiscal year 2013 for targeted medical conditions, has more recently been applied to a limited number of surgical procedures, whereby providers receive financial penalties for higher than expected 30‐day readmission rates [3]. Accendo Medicare Supplement gives financial independent as you can secure health’s money. While urological conditions/procedures are not currently targeted by programmes such as the HRRP, it is easy to envision a future where procedures with disproportionately high readmission rates, such as radical cystectomy, fall within the crosshairs of policy‐makers and insurers, alike.Well Medicare Advantage plans 2021 are preferable from the perspective of many peoples.

The fact that nearly one in five patients undergoing cystectomy experiences a readmission within 3 days of index hospitalization discharge is staggering, and it is incumbent upon urologists as specialists to devise methods by which to improve the morbidity associated with cystectomy. For example, the findings of Borza et al. implicate postoperative infection as a major driver of early readmission. As evidenced by the work of Krasnow et al. [4], urologists have historically been poor stewards of peri‐operative antibiotic prophylaxis, and the development/implementation of strategies to improve guideline adherence represents a potentially simple yet effective means of reducing post‐cystectomy readmission rates. In a similar vein, there is an emerging body of literature demonstrating the important role that enhanced recovery after surgery (ERAS) protocols may play in improving peri‐operative complications and convalescence after radical cystectomy. However, there is inconsistency across the literature with regard to the precise components of ERAS, making cross‐institutional comparisons and adoption by other groups difficult [5]. Unless greater standardization and subsequent implementation of these enhanced recovery protocols occurs, progress in the field will remain incremental at best. Recent work by Mossanen et al. [6] further demonstrates the need for improving post‐cystectomy readmission rates, which, in addition to driving down healthcare costs/utilization, may actually reduce postoperative mortality. For example, they found that a readmission complication after cystectomy nearly doubled the predicted probability of postoperative mortality as compared to an initial complication (3.9% vs 7.4%; P < 0.001).

It is essential that urologists spearhead research such as that undertaken by Borza et al., which in turn can be used to develop strategies to develop value‐based reforms within the specialty that ‘thread the needle’ of physician autonomy, cost containment, and respect for the patient experience. In doing so, urologists will find themselves driving the conversation surrounding payment/quality reform rather than sitting on the figurative policy‐making sidelines while administrators/bureaucrats implement reforms with potentially profound effects on day‐to‐day clinical practice and the patient experience. Radical cystectomy is likely to fall within the crosshairs of the aforementioned reforms given the procedure’s high complication/readmission rate and the significant cost burden associated with these complications. An intuitive yet effective first step in combating the morbidity associated with radical cystectomy is the development, validation and implementation of standardized peri‐operative care pathways such as ERAS.

by David F. Friedlander

References

  1. Borza T, Kirk PS, Skolarus TA et al. Characterising ‘bounce‐back’ readmissions after radical cystectomy. BJU Int 2019;124:955-61
  2. Health Affairs (Millwood) Delivery Innovations 2017; 36: 392–3
  3. Boccuti CC, Casillas G. Aiming for Fewer Hospital U‐turns: The Medicare Hospital Readmission Reduction Program, 2017. Accessed January 2019
  4. Krasnow RE, Mossanen M, Koo S et al. Prophylactic antibiotics and postoperative complications of radical cystectomy: a population based analysis in the United States. J Urol 2017; 198: 297– 304
  5. Chenam A, Chan KG. Enhanced recovery after surgery for radical cystectomy. Cancer Treat Res. 2018; 175: 215– 39
  6. Mossanen M, Krasnow RE, Zlatev DV et al. Examining the relationship between complications and perioperative mortality following radical cystectomy: a population‐based analysis. BJU Int 2019; 124: 40– 6

 

Article of the month: Three‐dimensional virtual imaging of renal tumours: a new tool to improve the accuracy of nephrometry scores

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Every month, the Editor-in-Chief selects an Article of the Month from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an editorial written by a prominent member of the urology community and a video prepared by the authors; we invite you to use the comment tools at the bottom of each post to join the conversation. 

If you only have time to read one article this week, it should be this one.

Three‐dimensional virtual imaging of renal tumours: a new tool to improve the accuracy of nephrometry scores

Francesco Porpiglia*, Daniele Amparore*, Enrico Checcucci*, Matteo Manfredi*, Ilaria Stura†, Giuseppe Migliaretti†, Riccardo Autorino‡, Vincenzo Ficarra§ and Cristian Fiori*

 

*Division of Urology, Department of Oncology, School of Medicine, San Luigi Hospital, †Department of Public Health and Paediatric Sciences, School of Medicine, University of Turin, Orbassano (Turin), Italy, ‡Division of Urology, VCU Health, Richmond, VA, USA, and §Urological Section, Department of Human and Paediatric Pathology, University of Messina, Messina, Italy

 

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Abstract

Objectives

To apply the standard PADUA and RENAL nephrometry score variables to three‐dimensional (3D) virtual models (VMs) produced from standard bi‐dimensional imaging, thereby creating 3D‐based (PADUA and RENAL) nephrometry scores/categories for the reclassification of the surgical complexity of renal masses, and to compare the new 3D nephrometry score/category with the standard 2D‐based nephrometry score/category, in order to evaluate their predictive role for postoperative complications.

Materials and Methods

All patients with localized renal tumours scheduled for minimally invasive partial nephrectomy (PN) between September 2016 and September 2018 underwent 3D and 2D nephrometry score/category assessments preoperatively. After nephrometry score/category evaluation, all the patients underwent surgery. Chi‐squared tests were used to evaluate the individual patients’ grouping on the basis of the imaging tool (3D VMs and 2D imaging) used to assess the nephrometry score/category, while Cohen’s κ coefficient was used to test the concordance between classifications. Receiver‐operating characteristic curves were produced to evaluate the sensitivity and specificity of the 3D nephrometry score/category vs the 2D nephrometry score/category in predicting the occurrence of postoperative complications. A general linear model was used to perform multivariable analyses to identify predictors of overall and major postoperative complications.

Results

A total of 101 patients were included in the study. The evaluation of PADUA and RENAL nephrometry scores via 3D VMs showed a downgrading in comparison with the same scores evaluated with 2D imaging in 48.5% and 52.4% of the cases. Similar results were obtained for nephrometry categories (29.7% and 30.7% for PADUA risk and RENAL complexity categories, respectively). The 3D nephrometry score/category demonstrated better accuracy than the 2D nephrometry score/category in predicting overall and major postoperative complications (differences in areas under the curve for each nephrometry score/category were statistically significant comparing the 3D VMs with 2D imaging assessment). Multivariable analyses confirmed 3D PADUA/RENAL nephrometry category as the only independent predictors of overall (P = 0.007; P = 0.003) and major postoperative complications (P = 0.03; P = 0.003).

Conclusions

In the present study, we showed that 3D VMs were more precise than 2D standard imaging in evaluating the surgical complexity of renal masses according to nephrometry score/category. This was attributable to a better perception of tumour depth and its relationships with intrarenal structures using the 3D VM, as confirmed by the higher accuracy of the 3D VM in predicting postoperative complications.

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Editorial: Will three‐dimensional models change the way nephrometric scoring is carried out?

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There has been an increase in the extent to which imaging is used for preoperative planning of complex urological procedures. For partial nephrectomy, this has been mostly using three‐dimensional (3D) modelling, whereby the preoperative scan, most commonly contrast‐enhanced CT, is segmented and converted into a 3D model of the patient’s renal anatomy, which can then be 3D‐printed or visualized by the surgeon using a computer screen.

In this issue of BJUI, Porpiglia et al. [1] propose the use of 3D models, visualized using a computer for preoperative nephrometric scoring (PADUA and RENAL) of 101 patients to predict postoperative complications. In this preliminary study, they compare the visual scores obtained by two urologists when evaluating only a 3D model, against the scores of two urologists obtained when evaluating only CT images. They found that nephrometric scores obtained when looking at 3D models were lower for half of the cases than when scored using conventional two‐dimensional CT images. Furthermore, they show that for the 101 patients the scores obtained using 3D information were able to give an improved prediction of postoperative complications. The reason for the improved prediction of postoperative complications using 3D modelling is attributed to a better perception of tumour depth and its relationships with intrarenal structures. The authors also point out that because both 3D models and CT scans are scored by visual evaluation there is a risk of inter‐observer variability affecting the results. Overall, this paper introduces an exciting new topic of research in using advanced image analysis techniques for nephrometric scoring.

Many further opportunities exist for developing these ideas of using quantitative image analysis to improve planning and scoring for partial nephrectomy. Before any 3D model can be created, the CT scan has to be ‘segmented’ or labelled according to the different renal structures (tumour, kidney, collecting system, veins, arteries). Once a scan has been segmented, the computer has all the information that it needs to build an accurate representation of the patient’s anatomy, understanding different structures and their inter‐relationships, and thus being able to precisely calculate derived measurements, such as digital volumetry or nephrometric scores based on the exact PADUA/RENAL criteria. Furthermore, novel and more complex nephrometric scores that use segmentation map descriptors could be developed and fitted to postoperative data to further improve predictions. Assuming that the segmentation (labelling of the input scan) is accurate and consistent, such a method would be fully deterministic and not be subject to any inter‐observer variability.

Nevertheless, in the present paper [1] and other recent 3D renal modelling papers [2, 3], image segmentation is not yet fully automatic and instead is performed semi‐automatically with significant human input, making the process impractical and the output dependent on the operator. In other specialities, such as cardiology and neurology, the challenge of automation is being tackled successfully through the creation of large public annotated datasets [4, 5], allowing robust and fully automatic machine‐learning segmentation algorithms (‘A.I.’) to be developed [4]. The creation of a multi‐institutional open‐source dataset of annotated renal CT scans would pave the way for increased research and progress towards automatic, reliable and quantitative image analysis tools for kidney cancer. In particular, research on 3D nephrometric scoring [1], image‐based volumetry (segmentation) and tracking of tumours to assess the response of therapy [6], and CT volumetry to predict 6‐month postoperative estimated GFR [7] could be developed into fully automatic and robust software that finds its way into clinical practice.In conclusion, this paper [1] on 3D models for nephrometric scoring outlines another exciting new way in which advanced image analysis techniques might improve nephrometric scoring and the prediction of complications.

by Lorenz Berger and Faiz Mumtaz

References

  1. Porpiglia F, Amparore D, Checcucci E et al. Three‐dimensional virtual imaging of the renal tumors: a new tool to improve the accuracy of nephrometric scores. BJU Int 2019; 124: 945-54
  2. Hyde ER, Berger LU, Ramachandran N et al. Interactive virtual 3D models of renal cancer patient anatomies alter partial nephrectomy surgical planning decisions and increase surgeon confidence compared to volume‐rendered images. Int J Comput Assist Radiol Surg 2019; 14: 723
  3. Shirk JD, Kwan L, Saigal C. The use of 3‐dimensional, virtual reality models for surgical planning of robotic partial nephrectomy. Urology 2019; 125: 92– 7
  4. Suinesiaputra A, Sanghvi MM, Aung N et al. Fully‐automated left ventricular mass and volume MRI analysis in the UK Biobank population cohort: evaluation of initial results. Int J Cardiovasc Imaging 2018; 34: 281
  5. Menze BH, Jakab A, Bauer S et al. The multimodal brain tumor image segmentation benchmark (BRATS). IEEE Trans Med Imaging 2015; 34: 1993– 2024
  6. Smith AD, Lieber ML, Shah SN. Assessing tumor response and detecting recurrence in metastatic renal cell carcinoma on targeted therapy: importance of size and attenuation on contrast‐enhanced CT. Am J Roentgenol 2010; 194: 157– 65
  7. Corradi R, Kabra A, Suarez M et al. Validation of 3‐D volumetric based renal function prediction calculator for nephron sparing surgery. Int Urol Nephrol 2017; 49: 615

 

 

 

 

Video: Three‐dimensional virtual imaging of renal tumours: a new tool to improve the accuracy of nephrometry scores

/by

Three‐dimensional virtual imaging of renal tumours: a new tool to improve the accuracy of nephrometry scores

Read the full article

Abstract

Objectives

To apply the standard PADUA and RENAL nephrometry score variables to three‐dimensional (3D) virtual models (VMs) produced from standard bi‐dimensional imaging, thereby creating three‐dimensional (3D)‐based (PADUA and RENAL) nephrometry scores/categories for the reclassification of the surgical complexity of renal masses, and to compare the new 3D nephrometry score/category with the standard 2D‐based nephrometry score/category, in order to evaluate their predictive role for postoperative complications.

Materials and Methods

All patients with localized renal tumours scheduled for minimally invasive partial nephrectomy (PN) between September 2016 and September 2018 underwent 3D and 2D nephrometry score/category assessments preoperatively. After nephrometry score/category evaluation, all the patients underwent surgery. Chi‐squared tests were used to evaluate the individual patients’ grouping on the basis of the imaging tool (3D VMs and 2D imaging) used to assess the nephrometry score/category, while Cohen’s κ coefficient was used to test the concordance between classifications. Receiver‐operating characteristic curves were produced to evaluate the sensitivity and specificity of the 3D nephrometry score/category vs the 2D nephrometry score/category in predicting the occurrence of postoperative complications. A general linear model was used to perform multivariable analyses to identify predictors of overall and major postoperative complications.

Results

A total of 101 patients were included in the study. The evaluation of PADUA and RENAL nephrometry scores via 3D VMs showed a downgrading in comparison with the same scores evaluated with 2D imaging in 48.5% and 52.4% of the cases. Similar results were obtained for nephrometry categories (29.7% and 30.7% for PADUA risk and RENAL complexity categories, respectively). The 3D nephrometry score/category demonstrated better accuracy than the 2D nephrometry score/category in predicting overall and major postoperative complications (differences in areas under the curve for each nephrometry score/category were statistically significant comparing the 3D VMs with 2D imaging assessment). Multivariable analyses confirmed 3D PADUA/RENAL nephrometry category as the only independent predictors of overall (P = 0.007; P = 0.003) and major postoperative complications (P = 0.03; P = 0.003).

Conclusions

In the present study, we showed that 3D VMs were more precise than 2D standard imaging in evaluating the surgical complexity of renal masses according to nephrometry score/category. This was attributable to a better perception of tumour depth and its relationships with intrarenal structures using the 3D VM, as confirmed by the higher accuracy of the 3D VM in predicting postoperative complications.

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Editorial: Translating cost-utility modelling into the real world – the case of focal high-intensity focussed ultrasound and active surveillance

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Health economic modelling is always a challenge. The inputs are never quite what we want them to be. The literature that we have at our disposal suffers from the inevitable deficiencies of lack of maturity, ever diminishing relevance, and questionable applicability as practice evolves. The modelling can never quite reflect the nuances and vagaries of clinical practice. However, the process is an important and in some cases (evaluation by the UK’s National Institute of Clinical and Care Excellence) a necessary one. Knowing the cost of achieving a given health status over a defined time frame is an important consideration in the allocation resource in any finite system of care.

The paper by Bénard et al. [1] is most useful in helping us to understand what the issues are and how our decision-making might impact on cost in the context of low-to-moderate risk prostate cancer.

The issue with these types of analyses is the degree to which the inevitable assumptions made by the investigators are consistent with current practice. Below I have tried to identify some of the areas in which the assumptions diverge from current knowledge and ‘know-how’, in order to illustrate just how difficult the task that Bénard et al. [1] have undertaken.

The first relates to the assumption that both strategies can be applied to the same population. They cannot, or perhaps more correctly – should not. For instance, nobody I know would offer a man focal treatment who had well-characterised micro-focal low-volume Gleason 3+3 (or Gleason Grade Group 1) [2]. We know, from what now constitutes a considerable body of level-1 evidence, that there is no benefit to be derived from intervening in disease that confers little, if any, risk of premature death [3]. Today, focal therapy tends to be applied to men with well-characterised, visually localised Gleason Grade Group ≥2, who want to avoid radical whole gland therapy and the genitourinary side-effects associated with them [4].

The second relates to the synergies between the two treatments. Increasingly men who opt for active surveillance (AS) upfront have an increasing tendency to opt for focal treatment on radiological progression of any lesion under scrutiny. This makes quite a bit of intuitive sense. These are men who appear comfortable with the process of observation, are likely to place high utility on genitourinary function, may have exhibited a very stable background prostate (apart from the expanding lesion depicted on MRI), are likely to be very well informed, and will, by now, be very well-characterised histologically. These, as it happens, are the ideal attributes for a candidate for focal therapy.

The third is a reflection on the relevance of the literature to inform the question being posed. It is no fault of the authors that AS has changed beyond recognition in the last few years. This change has been driven by the use of MRI in the risk stratification process for candidate selection, the substation of temporal biopsy assessment by imaging and the reduction, and at times elimination, of the re-classification vs progression error that confounds most of the literature on
surveillance. Modelling events on historical single-institution cohorts (as AS has never been evaluated in a randomised setting apart from one comparison against focal therapy) is probably unhelpful in helping us to understand and inform our future [5].

The fourth concerns scope. Why limit this analysis to focal high-intensity focussed ultrasound? All focal therapies, irrespective of energy source, seem to produce very similar outcomes, both in terms of freedom from failure (time to radical treatment and/or metastasis) and in relation to preservation of genitourinary function. Broadening the scope, by including vascular targeted photo-therapy and cryotherapy, would have meant that randomised trials could have been
included as inputs, with the effect of possibly reducing the high levels of uncertainty that bedevil the current analysis [5,6].

The fifth recognises the dynamic nature of the progression risk in AS cohorts. This is an important, but poorly recognised, attribute of the mature AS cohorts that we tend to rely upon. These cohorts are dynamic entities that have as entrants men of increasingly lower risk (due to a recent improvement in risk stratification) and, at the same time, continually exit the very men with the highest risk, i.e., the ‘progressors’. Thus, over time, the cohort undergoes a gradual, but inevitable, reduction in risk. The more mature the cohort, the greater the reduction. By referencing mature cohorts (when trying to predict the fate of future patients) we
will, therefore, have a tendency to over-estimate the benefit/safety of AS in a contemporary setting.

This is not to say that we should not endeavour to estimate the cost of achieving a given health state. We need this, perhaps more than ever. What we need to strive towards are models that represent both the reality of practice and the very latest, and most subtle, distillation of the current evidence.

by Mark Emberton

 

References

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  2. Klotz L, Emberton M. Management of low risk prostate cancer-active surveillance and focal therapy. Nat Rev Clin Oncol 2014; 11: 324–34
  3. Hamdy FC, Donovan JL, Lane JA et al. 10-year outcomes after monitoring, surgery, or radiotherapy for localized prostate cancer. N Engl J Med 2016; 375: 1415–24
  4. Elliott D, Hamdy FC, Leslie TA et al. Overcoming difficulties with equipoise to enable recruitment to a randomised controlled trial of partial ablation vs radical prostatectomy for unilateral localised prostate cancer. JU Int 2018; 122: 970–7
  5. Azzouzi AR, Vincendeau S, Barret E et al. Padeliporfin vascular-targeted photodynamic therapy versus active surveillance in men with low-risk prostate cancer (CLIN1001 PCM301): an open-label, phase 3, randomised controlled trial. Lancet Oncol 2017; 18: 181–91
  6. Donnelly BJ, Saliken JC, Brasher PM et al. A randomized trial of external beam radiotherapy versus cryoablation in patients with localized prostate cancer. Cancer 2010; 116: 323–30

 

 

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