Use of monopolar versus bipolar transurethral resection in non-muscle-invasive bladder tumors related to thermal artifact and recurrence and progression rates
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BACKGROUND: Bladder cancer is the 10th most common malignant tumor worldwide.
75% of cases are diagnosed at a non-muscle-invasive stage, 90% being of urothelial
origin. The management of non-muscle-invasive bladder tumors is based on
transurethral resection and the application of adjuvant intravesical therapy. Their main
drawback is that they have a high recurrence rate and may progress to a more advanced
stage. It exists two main modalities of transurethral resection: monopolar (gold
standard) and bipolar systems. The last one has proven to have significant advantages
over monopolar energy, such as reducing the presence of thermal artifact in tissue
samples, which may interfere in the pathological diagnosis, the basis for the
management of these patients. However, there is still controversy about if this reduction
have a significant impact on the histological analysis. The recurrence and progression
rates decrease with the intravesical therapy, but there are no consistent studies that
have evaluated the impact of using one modality of resection or another on these rates.
OBJETIVE: to demonstrate that the use of bipolar transurethral resection in bladder
urothelial carcinomas (non-muscle-invasive) reduce the presence of thermal artifact in
tissue samples, allowing a proper pathological diagnosis and, consequently, a decrease
in the recurrence and progression rates, in comparison to the use of monopolar systems.
DESIGN: It will be a multicenter, longitudinal, prospective, parallel-group, double-blind,
randomized and controlled clinical trial carried out in 4 hospitals of Cataluña.
METHODS: Study subjects will be those newly diagnosed of bladder papillary tumors
highly suspicious of urothelial carcinoma. They will be classified in 2 groups (as negative
or positive cytology) and these will be randomized in 2 groups of intervention (undergo
bipolar or monopolar transurethral resection). The pathologist will analyze the thermal
artifact and other parameters. The patients will be classified in 3 risk groups (low,
intermediate, and high), treated and followed-up for 1 year to evaluate the percentage
of recurrence and progression. The sample size will be about 850 patients and
recruitment of patients will last 15 months