An interventional study of CURTIS retrieval device in Bladder Cancer and Bladder Cancer TNM Staging Primary Tumor (T) T1, sponsored by Ludwig-Maximilians - University of Munich. Not yet recruiting at 9 sites in 3 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-17.
Sponsored by Ludwig-Maximilians - University of Munich · Not applicable, Interventional, and Diagnostic
Bladder cancer is the most common malignancy of the urinary tract, and approximately 75% of cases are non-muscle invasive (NMIBC) at diagnosis. The standard treatment is transurethral resection of the bladder tumor (TURBT). En bloc resection (EBR-T), in which the tumor is removed in one intact piece rather than fragmented, offers superior pathological specimen quality and may reduce the need for repeat resections. However, extracting the intact specimen from the bladder through the urethra remains a critical technical challenge, particularly for larger tumors.
CURTIS (Urotech GmbH) is a CE-marked retrieval device consisting of a hydrophilic-coated bag that can be opened and closed via a handpiece, enabling controlled capture and safe transurethral extraction of the resected tumor specimen.
This study aims to evaluate the technical feasibility of CURTIS-assisted intact specimen retrieval following en bloc transurethral resection of primary NMIBC. The central question the study seeks to answer is: in what proportion of cases can CURTIS successfully retrieve an intact en bloc resected bladder tumor, and what is the maximum tumor size for which intact retrieval remains feasible?
Here is the Detailed Description for ClinicalTrials.gov:
Study Design The RETRIEVE-BT Trial is a prospective, multicenter, single-arm, non-randomized feasibility study conducted at multiple urological centers. No control group or randomization is applied, as the study is designed to characterize the technical performance of the CURTIS device under real-world clinical conditions rather than to test a comparative efficacy hypothesis.
The CURTIS Device CURTIS (Urotech GmbH, Achenmühle, Germany) is a CE-marked medical device specifically developed for transurethral retrieval of intact bladder tumor specimens following en bloc resection. The device consists of a hydrophilic-coated retrieval bag that can be opened and closed via a handpiece, enabling controlled capture and safe transurethral extraction of the resected specimen. It is used within its approved intended purpose as defined by EU MDR 2017/745.
Surgical Procedure All procedures are performed under general or spinal anesthesia. En bloc transurethral resection is carried out using a standard resectoscope with an appropriate electrode (e.g., bipolar hook, J-electrode, or needle electrode). A circumferential incision is made in healthy urothelium approximately 3-5 mm lateral to the visible tumor margin, followed by en bloc dissection at the submucosal or muscularis propria level. Once the specimen is fully detached from the bladder wall, CURTIS-assisted retrieval is attempted according to the manufacturer's instructions for use. If retrieval with CURTIS is unsuccessful, conversion to an alternative extraction method is performed at the surgeon's discretion and documented.
Data Collection and Follow-up Data are collected prospectively via an electronic Case Report Form (eCRF). Intraoperative variables recorded include retrieval success or failure, reason for failure if applicable, total procedure time, and dedicated retrieval time. Resected specimens are processed by the local pathology department according to institutional standards; pathological variables include specimen dimensions, muscularis propria presence, pathological T-stage, histological grade (WHO 2022), and resection margin status. Postoperative complications are documented according to the Clavien-Dindo classification until hospital discharge. No additional study-specific outpatient follow-up visits are required.
Statistical Approach This is a pilot feasibility study; the statistical approach is primarily descriptive. The primary endpoint will be reported as an observed proportion with exact 95% Clopper-Pearson confidence interval. A predefined technical feasibility rate of ≥80% is the threshold indicating clinical utility. Secondary endpoints will be analyzed descriptively. A threshold analysis will be applied to identify the maximum tumor size associated with successful intact retrieval.
1,798 studies on the registry are indexed under Urinary Bladder Neoplasms; 445 are open to participants now.
This study's planned enrollment of 75 is above the median of 60 across 1,296 interventional studies indexed under Urinary Bladder Neoplasms.
Browse Urinary Bladder Neoplasms studies →Ludwig-Maximilians - University of Munich is the lead sponsor of 223 studies on the registry; 29 are open to participants now.
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Exclusion Criteria:
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Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
En-bloc resection and retrieval of the tumor with CURTIS device
Device: CURTIS retrieval device
After successful en-bloc resection, the tumor is retrieved using the novel retrieval device, where the tumor is catched with a bag and removed through the urethra
Technical Feasibility Rate of CURTIS-Assisted Intact Specimen Retrieval
Proportion of enrolled patients in whom the CURTIS device enables complete, intact retrieval of the en-bloc resected bladder tumor specimen without fragmentation within the bladder or urethra. A case is classified as a technical success if the entire resected specimen is extracted through the urethra in one piece using the CURTIS device. Cases requiring conversion to an alternative retrieval method (e.g., piecemeal extraction, Ellik evacuator, endoscopic bag) are classified as technical failures.
Time frame: Intraoperatively (single assessment at the time of specimen retrieval during the index surgical procedure)
Maximum Retrievable Tumor Size
Largest tumor diameter (in mm) at which successful intact retrieval using CURTIS was achieved, used to define a clinically meaningful upper size limit for CURTIS-assisted EBR-T.
Time frame: Intraoperatively (measured at time of specimen retrieval)
Proportion of Specimens Containing Muscularis Propria (Detrusor Muscle)
Proportion of retrieved specimens containing detrusor muscle on pathological examination.
Time frame: Perioperative/Periprocedural
Proportion of Specimens Permitting Complete Pathological T-Stage Assessment
Proportion of retrieved specimens allowing complete pathological T-stage assessment (pTa/pT1/pT2+).
Time frame: Perioperative/Periprocedural
Proportion of Specimens Permitting Histological Grading
Proportion of retrieved specimens permitting grading according to WHO 2022 classification.
Time frame: Perioperative/Periprocedural
Proportion of Specimens Permitting Resection Margin Assessment
Proportion of retrieved specimens permitting assessment of horizontal and vertical resection margin status.
Time frame: Perioperative/Periprocedural
Total Procedure Time
Time from cystoscope insertion to complete specimen extraction and withdrawal of all instruments.
Time frame: Intraoperatively (during the index surgical procedure)
Retrieval Time
Time from completion of en-bloc resection (detachment of tumor from bladder wall) to complete specimen extraction through the urethra.
Time frame: Intraoperatively (during the index surgical procedure)
Perioperative Complication Rate (Clavien-Dindo Classification)
All intraoperative and postoperative complications occurring from the start of the procedure until hospital discharge, up to 30 postoperative days, classified according to the Clavien-Dindo classification system.
Time frame: From start of procedure until hospital discharge, up to 30 days postoperatively
Plan to share: No — Not able due to ethical and legal obligations
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Start is estimated for Sep 2026; primary completion for Dec 2026, 3 months later.
Of 235 non-industry interventional studies with no phase under Urinary Bladder Neoplasms, half reached primary completion within 40 months of starting (the median), counting those still running; a quarter within 21 and three quarters within 70. This study's planned 3 months is below that.
Counting every sponsor, half of 244 studies reached it within 39 months; a quarter within 20 and three quarters within 69.
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This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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