High-power Green-light Laser Endoscopic Submucosal Dissection for Non-muscle-invasive Bladder Cancer

March 18, 2022 updated by: Muwen Wang, Shandong Provincial Hospital

High-power Green-light Laser Endoscopic Submucosal Dissection for Non-muscle-invasive Bladder Cancer: a Technical Improvement and Its Initial Application

A retrospective study was designed in this study. The surgeon performed high-power green-light laser endoscopic submucosal dissection (HPL-ESD) for the treatment of primary non-muscle-invasive bladder cancer (NMIBC). This surgical treatment was novel and safety and efficacy of the treatment has not been established. We collected relative data in Shandong Provincial Hospital Affiliated to Shandong First Medical University from May 2018 to December 2020. Preoperative, intraoperative and postoperative clinical data were collected and analysed. The safety and efficacy of the novel surgical treatment were verified by the short-term and long-term clinical outcomes. Fifty patients with NMIBC were planed to be enrolled in the study.

Study Overview

Status

Completed

Conditions

Detailed Description

Background: In recent years, endoscopic laser surgery has been introduced to the treatment of NMIBC. Various types of laser (holmium laser, thulium laser and green-light laser) have been examined in the treatment of NMIBC, and the cutting power has been raised gradually. In our previous study, a 120 W green-light laser was used to perform en bloc resection, which yielded encouraging results. Endoscopic submucosal dissection by the HybridKnife was reported to be safe and effective in the treatment of NMIBC. However, previous resection was performed by electrical instrument. To further enhance the safety and accuracy of the operation, surgeons improved the treatment by combining laser resection and endoscopic submucosal dissection (ESD). This novel surgical treatment can also integrate advantages of each method. A retrospective study was designed in this study. The aim of the study was to evaluate the safety and efficacy of this novel surgical treatment, high-power green-light laser endoscopic submucosal dissection (HPL-ESD), in the treatment of primary non-muscle-invasive bladder cancer (NMIBC).

Introduction: Greenlight lasers are developed from Nd:YAG laser. Visual laser vaporization with Nd:YAG laser was introduced for the treatment of bladder cancer in the early 1990s. However, the low-absorption in most tissues with a penetration depth of 4-18mm leading to a deep coagulative necrosis of tissue, which increased the risk of delayed bladder perforation and bowel injury. Passing the Nd:YAG-produced beam (1046nm) through a KTP or LBO crystal, leads to a green visible light beam of 532nm, which has a completely different laser beam-tissue interaction. The wavelength is not absorbed by water but strongly absorbed by hemoglobin, which limits the optical penetration depth of green light laser to 0.8 mm, and the heat remaining in the tissue induces a coagulation zone of only 1-2mm thickness. Recent studies show that greenlight laser vaporization is a reliable and feasible treatment for the patients with primary NMIBC compared with standard TURBT.

On the basis of our previous surgical procedure, we developed this new surgical method by introducing ESD technology. Thus LBO laser en bloc resection was combined with the ESD technique to treat NMIBC, which was inspired by waterjet-assisted ESD in the department of gastroenterology. ESD was developed from endoscopic mucosal resection (EMR) and widely applied for the treatment of early gastroesophageal cancer and colorectal neoplasms. The bladder wall shares a similar histological structure with the gastrointestinal tract, although the muscularis propria is thicker. Therefore, forming a submucosal fluid cushion in the bladder wall should be feasible and even safer. The effects of submucosal fluid cushion on bladder wall were showed intuitively. The interspace between the mucosal layer and the detrusor muscle layer was increased, and the tissue between the two layers was rendered looser. In the present study, the submucosal fluid cushion increases safety during the operation. More importantly, when the normal mucosa was incised, the detrusor muscle layer beneath was exposed, which facilitated distinction of which layer was reached and incision of the entire tumor with the superficial detrusor muscle beneath the basal part. To some extent, introduction of the ESD technique enabled safe, controllable and accurate incision.

Equipment: The equipment included a 23F continuous flow resectoscope through which a 6F green-light lithium triborate (LBO) laser fiber (Realton, Beijing, China) could be delivered via the working channel. In addition, a disposable injector was used to form the submucosal fluid cushion for ESD. The stainless steel needle of the injector is 5 mm in length and 0.6 mm in diameter (terminal part). The working length and diameter are 1650 mm and 2.5 mm respectively (middle part), enabling delivery through the working channel of the resectoscope. The beginning part of the injector was connected to a 20-ml syringe containing methylene blue solution as the injection fluid.

HPL-ESD procedure: All surgeries were conducted in the lithotomy position under continuous epidural anesthesia. Sodium chloride physiological solution was used for irrigation. The 23F continuous flow resectoscope was delivered into the bladder through the urethra initially. Each visible tumor was examined to confirm the location, number, and size and the condition of the adjacent mucosa. Then, the 6F green-light LBO laser fiber was delivered through the working channel of the resectoscope. Each tumor was first marked with a circular coagulation blockage border, which was 1-2 cm from the edge of the tumor. Next, the laser fiber was temporarily withdrawn and the disposable injector was delivered through the same working channel of the resectoscope. Multipoint injection was performed in the normal mucosa along the blockage border. Because the tissue between the mucosal layer and the detrusor muscle layer in the bladder wall is relatively loose, a blue submucosal fluid cushion was formed between the two layers after injection. Subsequently, the green-light laser was delivered through the working channel again. The laser power was set at 160 W for cutting and 30-50 W for coagulation simultaneously. The mucosa was incised annularly, and the detrusor muscle layer beneath it was gradually exposed. The submucosal fluid cushion separated the mucosa layer and the detrusor muscle layer to some extent in advance. Therefore, the course and distribution of the detrusor muscle could be clearly observed. Dissection of tissue connected between the tumor and the bladder wall was also facilitated. The entire tumor was excised with superficial detrusor muscle beneath the basal part. After resection, the whole tumor bed and surrounding mucosa were carefully coagulated at a power of 30-50 W. The intact bladder tumor was removed with an alligator forceps or flushed out with an Ellik evacuator. When the tumor size was > 3 cm, the specimen was longitudinally cut into two or more parts.

Clinical data will be collected, such as patient data, tumor characteristics, and perioperative data.

Study Type

Observational

Enrollment (Actual)

45

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Shandong
      • Jinan, Shandong, China, 250000
        • Shandong Provincial Hospital Affiliated to Shandong First Medical University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 88 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Patients with primary non-muscle invasive bladder cancer that received high-power green laser submucosal resection will be enrolled in this study. Gender is not limited. Most patients were elder male people with smoking history.

Description

Inclusion Criteria:

  • Patients with non-muscle invasive bladder cancer who received high-power green laser submucosal resection of bladder tumor

Exclusion Criteria:

  • Patients with muscle invasive bladder cancer
  • Patients with recurrent bladder cancer
  • Patients with benign bladder tumor

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Success rate of the surgery
Time Frame: after all data has been collected, analysis will be finished within 5 days
The success of the surgery was NMIBC got en bloc resection by HPL-ESD without transfering to other treatment. Success rate of the surgery is the proportion of surgery success in all surgery.
after all data has been collected, analysis will be finished within 5 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rate of tumor en bloc resection
Time Frame: after all data has been collected, analysis will be finished within 5 days
The proportion of tumor en bloc resection (R0 resection) in all resected tumors.
after all data has been collected, analysis will be finished within 5 days
Operative time
Time Frame: after all data has been collected, analysis will be finished within 5 days
The time from the installation of endoscopic instrument to the complete resection of bladder tumor
after all data has been collected, analysis will be finished within 5 days
Hemoglobin decrease
Time Frame: after all data has been collected, analysis will be finished within 5 days
Hemoglobin decrease (g/dL) = preoperative serum hemoglobin (g/dL) - postoperative serum hemoglobin (g/dL)
after all data has been collected, analysis will be finished within 5 days
Catheterization time
Time Frame: after all data has been collected, analysis will be finished within 5 days
Time from indwelling catheter intraoperatively to removing catheter postoperatively
after all data has been collected, analysis will be finished within 5 days
Hospital stay
Time Frame: after all data has been collected, analysis will be finished within 5 days
The hospital stay is the total number of days from the admission to the discharge of patients
after all data has been collected, analysis will be finished within 5 days
Complication
Time Frame: after all data has been collected, analysis will be finished within 5 days
Obturator nerve reflex, perforation, urethral stricture, hydronephrosis
after all data has been collected, analysis will be finished within 5 days
The recurrence rate of tumor in situ
Time Frame: after all data has been collected, analysis will be finished within 5 days
The proportion of patients with postoperative tumor recurrence in situ in all patients after a 12-month follow-up
after all data has been collected, analysis will be finished within 5 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Shandong Provincial Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 1, 2018

Primary Completion (Actual)

December 30, 2020

Study Completion (Actual)

March 18, 2022

Study Registration Dates

First Submitted

March 18, 2022

First Submitted That Met QC Criteria

March 18, 2022

First Posted (Actual)

March 22, 2022

Study Record Updates

Last Update Posted (Actual)

March 22, 2022

Last Update Submitted That Met QC Criteria

March 18, 2022

Last Verified

March 1, 2022

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SWYX:NO. 2022-085

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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