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ORIGINAL ARTICLE Table of Contents  
Ahead of print publication
Comparison between En bloc Resection and conventional resection of bladder tumor in perioperative and oncological outcomes

1 Department of Urology, Kaohsiung Chung Gung Memorial Hospital, Kaohsiung, Taiwan
2 Department of Urology, Kaohsiung Chung Gung Memorial Hospital; Department of Urology, Jhong Siao Urological Hospital, Kaohsiung, Taiwan

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Date of Submission30-Nov-2022
Date of Decision19-Jan-2023
Date of Acceptance20-Mar-2023
Date of Web Publication26-May-2023


Purpose: Conventional transurethral resection of bladder tumors (cTURBT) has been the main technique for treating visible bladder tumor for decades. However, the reported rate of detrusor muscle presence in cTURBT specimen was lower than 80%, which is associated with imprecise staging and poor prognosis. Here, we present a retrospective analysis to compare the detrusor muscle detection rate and outcomes between en bloc resection of bladder tumor (ERBT) and cTURBT. Materials and Methods: Between January 2016 and December 2019, a total of 150 procedures performed by single surgeon in single institute were reviewed in this study. Of these procedures, 41 (27.3%) were ERBT and 109 (72.6%) were cTURBT. The two techniques were compared for pathological detrusor muscle detection, history of upper tract urothelial cancer, number of tumor lesions, histopathological grading and staging, time of operation, and time of catheterization and hospitalization. Results: The muscularis propria detection rate was statistically significantly higher in the ERBT group than in the cTURBT group (82.9% vs. 43.1%, P < 0.0001). The multivariate analysis showed resection method as an independent factor of detrusor muscle presentation (P < 0.0001). The mean Foley catheter indwelling and hospitalization days were longer in the ERBT group but were only 1 day longer than in the cTURBT group. Conclusions: ERBT significantly increases the muscularis propria detection rate than cTURBT. ERBT can provide more accurate cancer staging and contribute to proper decision-making. This study strengthens ERBT as a feasible and promising management of bladder cancer.

Keywords: Bladder tumor, en bloc resection, en bloc resection of bladder tumor, muscularis propria

How to cite this URL:
Chiang PC, Chiang PH, Luo HL. Comparison between En bloc Resection and conventional resection of bladder tumor in perioperative and oncological outcomes. Urol Sci [Epub ahead of print] [cited 2023 Jun 1]. Available from: https://www.e-urol-sci.com/preprintarticle.asp?id=377646

  Introduction Top

Transurethral resection of bladder tumor (TURBT) is the first-line procedure for diagnosing, staging, and treating visible bladder tumors.[1] Complete resection can be achieved either by conventional TURBT (cTURBT) or by en bloc resection of bladder tumor (ERBT) technique.[2]

Although cTURBT has been the most widely used procedure for decades, it has multiple drawbacks. These include fragmentation and thermal damage of the specimen, tumor cell seeding and reimplantation, incomplete resection, and obturator nerve reflex with bladder perforation.[3],[4] Moreover, lower rates of detrusor muscle detection are a concern.[2],[5] The presence of detrusor muscle in the specimen is a key marker of the quality and completeness of resection.[6] The absence of a muscularis layer in the specimen is also associated with a significantly higher disease progression rate and lower recurrence-free survival rate.[7],[8],[9],[10] Unfortunately, studies report a rate of detrusor muscle presence in cTURBT lower than 80%.[8],[11] Further, cTURBT can cause specimen fragmentation and irreversible cauterization damage. There is negligible room for improvement in detrusor muscle detection rates to enhance the quality of resection. By contrast, ERBT was reported to achieve a high detrusor muscle detection rate of up to 95%.[2]

We retrospectively reviewed patients with bladder cancer who underwent operations at our institute to compare the detrusor muscle detection rates of ERBT and cTURBT and determine the most effective technique.

  Materials and Methods Top

Patients and procedures

This retrospective study initially enrolled 153 adult patients (197 procedures). The inclusion criteria were age above 18 years, resection of bladder tumor by an experienced surgeon in a single institution, either newly diagnosed or recurrent, and either single or multifocal bladder tumor. The exclusion criteria were cup biopsy only, second TUR for cancer restaging, benign lesion, and absence of specimen from an operation. All patients were blinded to the allocated arm. The surgical method was at the operator's discretion, according to previous experience. A bipolar resectoscope equipped with a Loop or Colin knife was used for each procedure. The ERBT technique featured blunt dissection within the muscular layer using an intermittent electric current. The tumor was completely resected, “pushed” away from the bladder wall [Figure 1], [Figure 2], [Figure 3], and finally pulled out in one piece through the working channel of the endoscope. No additional sampling of the tumor bed was performed. The resected tumors were sent for pathological confirmation at the same hospital and interpreted in a standard format.
Figure 1: ERBT features on intermittent electric current

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Figure 2: The “push” technique is widely used during ERBT

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Figure 3: Muscle fibers are visible over tumor base

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Collection of clinical data

The medical records of patients who underwent bladder tumor surgery at Kaohsiung Chang Gung Memorial Hospital were retrospectively reviewed. After excluding incomplete data, 150 procedures performed by a single surgeon between January 2016 and December 2019 were enrolled. Of the 150 procedures, 41 (27.3%) were ERBT and 109 (72.6%) cTURBT. Clinical characteristics included detrusor muscle detection, a history of upper tract urothelial cancer, the number of tumor lesions, histopathological grading and staging, and the duration of operation, catheterization, and hospitalization. This study was approved by the Chang Gung Medical Foundation Institutional Review Board (approval number: 202100160B0) and complied with the Declaration of Helsinki and the Medical Care Act of Taiwan. For this type of study, formal consent is not required.

Statistical analysis

Statistical analysis was conducted using SPSS for Windows (version 20.0; IBM Corporation, Armonk, NY, USA). For the baseline characteristics of the two surgical techniques, measurement data were compared using independent t-tests and the Mann–Whitney U-test; categorical variables were compared using the Pearson Chi-square and Fisher's exact tests. Univariate and multivariate logistic regression analyses were used to investigate which parameter was related to the presence of the detrusor muscle P < 0.05 was considered statistically significant.

  Results Top

There was no difference between the baseline patient characteristics of the ERBT and cTURBT groups [Table 1].
Table 1: Baseline patient characteristics

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The detrusor muscle detection rate was statistically significantly higher in the ERBT group (82.9%) than in the cTURBT group (43.1%) [Table 2]. There was no significant difference in tumor size, rate of tumor size >3 cm, the rate of location around the dome, the final pathological stage, and operation time. The mean duration of Foley catheter indwelling, and hospitalization was longer in the ERBT group, but only by 1 day. No patient experienced obturator nerve reflex-related bladder perforation. No Clavien-Dindo grade III or IV perioperative complications were observed in this series.
Table 2: Perioperative and oncological outcomes

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Univariate and multivariate analyses were performed for detrusor muscle detection rates. The resection method is considered an independent factor for detrusor muscle presentation with a P < 0.0001 [Table 3].
Table 3: Univariate and multivariate analysis for parameters of detrusor muscle detection rate

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  Discussion Top

The concept of ERBT was first presented by Dr. Kawada in 1997 using rotational resection with a monopolar J-hook electrode.[12] Since then, reports of different techniques have gradually emerged.[13] ERBT can be performed with either a monopolar or bipolar resectoscope. Energy sources such as the Holmium laser, have been reported to achieve similar resection outcomes while preventing the obturator nerve reflex.[14],[15] The choice depends on the tumor size and operator's experience. A recent study found that a tumor size over 3 cm is a predictor of ERBT success, regardless of the patient's gender, tumor location, stage, grade, and lesion number.[16]

Current treatment guidelines for managing bladder cancer differ depending on whether there is muscularis layer invasion. A second TURB within 2–6 weeks is indicated for initial incomplete resection, negative muscle sampling, and all T1 tumors.[1] Pathological detrusor muscular involvement is also a pivotal point in defining the quality and efficacy of TURBT. Muscularis propria layer detection affects T1 tumor sub-staging and decision-making. If muscle-invasive bladder cancer is diagnosed, intensive treatment, including radical cystectomy with neoadjuvant chemotherapy or immunotherapy, is indicated.

To the best of our knowledge, this is the first study focusing on data from a single experienced surgeon. This eliminates the bias arising from differing surgical techniques and hospital strategies. Our results showed that ERBT significantly increased the muscularis propria layer detection rate from 43.1% to 82.9% (P < 0.0001). A lower muscle detection rate than in published studies was observed for cTURBT in our institution.[8] Fortunately, our study revealed that significantly improved muscularis layer sampling could be achieved simply by changing the surgical method. Pathologists' interpretation of specimens may also affect the histopathological results. A recent study of bladder cancer muscle layer detection quality showed that ERBT required less diagnostic time and provided more accurate pT1 sub-staging by different pathologists.[17]

There was no significant difference in the operation time of ERBT and cTURBT in our study. Conversely, the mean Foley indwelling period and hospitalization times were 1 day longer in the ERBT group than in the cTURBT group. Since the ideal time for catheter removal and discharge depends on the surgeon, the longer duration might arise from caution due to use of the newer surgical technique. In a systematic review and meta-analysis based on 13 randomised controlled trials, the forest plot revealed that ERBT had a longer operative time (mean difference 5.38 min, 95% confidence interval [CI] 0.33–10.4, z = 2.09) and shorter catheterization period than cTURBT (mean difference 1.07 days, 95% CI − 1.63 to − 0.51, z = 2.09).[18] A prospective controlled multicenter study suggested no difference in catheter indwelling time, but shorter hospitalization in the ERBT group.[19] Despite the statistical differences in the reported data, it is questionable whether they are clinically significant.

In this cohort, there was no significant difference in the mean tumor size between ERBT and cTURBT (2.33 ± 1.06 cm vs. 2.18 ± 1.42 cm, P = 0.201). It was feasible to perform ERBT for bladder tumors up to 4.5 cm. A published series suggested that the upper limit of tumor size is 3 or 4 cm;[20] however, there is a report of ERBT being used on a tumor 6 cm in size.[16] The aim of en bloc resection is to harvest the cancer tissue with the whole layer. Since the texture of urothelial cancer is soft and puffy, in our patients, large specimens could be taken out during evacuation along with the removal of the resectoscope sheath.

The ERBT procedure can be affected by factors such as tumor location. Some studies excluded bladder tumors around the dome because of the greater difficulty of en bloc resection.[20] In this cohort, the rate of tumor around the bladder dome was 4.9% in the ERBT and 13.8% in the cTURBT group, however, it was not statistically significant (P = 0.157). In our experience, ERBT was feasible for resecting intravesical tumors in any location. Suprapubic compression by an assistant aids access to the tumor around the bladder dome.

This study had several limitations. First, the sample size was relatively small, and was based in Taiwan. Second, the enrolled cohort was nonrandomized. The surgeon chose between ERBT and cTURBT according to preference and experience, so there may be selection bias. Compared with the decades of cTURBT experience, these were among the surgeon's first 50 ERBT cases. In a European study, the main reasons for not choosing ERBT included tumor removal difficulty, technical skills, and safety concerns, which can be overcome with appropriate training programs.[21] An Indian single-center study reported that the rate of postoperative bladder irrigation and blood clot evacuation decreased as surgeons acquired experience and ascended the ERBT learning curve.[22] Third, although no bladder perforation related to the obturator nerve reflex was observed, a lack of delicate intraoperative complications was recorded in this study. To date, there is no standardized classification of bladder perforation. A randomized controlled trial proposed the Depth of Endoscopic Perforation scale, which may provide a better indication of the major complications of bladder tumor resection.[23] Finally, tumor recurrence and disease prognosis are not well documented in this study. Published recurrence-free survival showed great heterogeneity due to deficiencies in long-term follow-up. Further well-designed large-scaled trials are needed to provide robust oncologic outcomes.

  Conclusions Top

ERBT achieves a significantly higher muscularis propria detection rate than cTURBT. ERBT can provide more accurate cancer staging and contribute to better decision-making. This study supports ERBT as a practical and promising technique for managing bladder cancer.


The author wishes to acknowledge the help of Prof. Po-Hui Chiang in providing clinical data. The work is enhanced by the advice and assistance of Dr. Hao-Lun Luo. We would like to thank reviewers and the editor for their invaluable comments.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Full text]  
Breda A, Gallioli A, Diana P, Fontana M, Territo A, Gaya JM, et al. The DEpth of endoscopic perforation scale to assess intraoperative perforations during transurethral resection of bladder tumor: Subgroup analysis of a randomized controlled trial. World J Urol 2022. p. 1-7.  Back to cited text no. 23

Correspondence Address:
Ping- Chia Chiang,
No. 123, Dapi Road, Niaosong, Kaohsiung City 83301
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/UROS.UROS_133_22


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2], [Table 3]


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