Category: Basic Science: Oncology

MP1-6 - Morphological aspects of laser (thulium) en bloc and conventional transurethral resection of bladder cancer.

Thu, Sep 20
4:00 PM - 6:00 PM

Introduction & Objective :

Surgical treatment of non-muscle-invasive bladder cancer (NMIBC) aims to completely remove all lesions as well as  obtain a high quality specimen. Tumor grading and muscular invasion are the most important parameters influencing on treatment strategy and prognosis. Previous studies have shown that thulium en bloc resection of bladder tumors (ThERBT) provides a high quality  specimen with the muscle layers  in 96-100% of cases, while conventional transurethral resection of bladder tumors (cTURB) in only 50-86% of cases. Thulium laser allows to perform very precise resection of bladder wall layers with muscle fibers easily identified. Since the specimen is resected with surrounding mucosa during ThEBR, the horizontal surgical margin can be assessed. We looked at morphological characteristics of ThERBT and cTURB specimens.


Methods :

26 patients with cT1 bladder cancer (16 - ThERBT group and 10 – cTURB group) were enrolled. The average tumor size was 17 mm (7 – 28 mm) and 15 mm (5 – 25 mm) in two groups respectively. ThERBT were performed with 1.94 µm thulium fiber laser Urolase (IRE-Polus, Russia), 1J x 10 Hz settings.  Presence of muscle layer, the depth and extent of the lamina propria invasion, the depth of the specimen thermal damage were evaluated. Additionally, horizontal surgical margin was assessed.


Results :

Muscle layer was more often identified in the ThERBT group - 15 cases (94%) then in the cTURB group - 6 cases (60%), p<0.05. The lamina propria invasion was possible to assess in all ThERBT specimens and was detected in 13 cases (81%); in cTURB group only in 3 cases (30%) it was possible to evaluate the lamina propria invasion and in 2 of them it was found (p<0.05).The depth of thermal damage of specimens in ThERBT group did not exceed 1 mm in all cases, while in cTURB group it was on average 1.8 mm (1.0 – 3.0 mm), p<0.05. There was a rim of macroscopically intact mucosa around the tumor so the horizontal surgical margin was evaluated in all ThERBT specimens. The ability to assess the horizontal surgical margin in cTURB group was in 40%.


Conclusions :

Specimens obtained with ThERBT are significantly provide more accurate information for staging compared with that obtained with cTURB due to less damage of tissue samples, enhanced ability to evaluate the lamina propria and muscle layer invasion. This allows to choose correct treatment strategy and avoid unnecessary second TURB.

Alim Dymov

Urologist
Sechenov University
Moscow, Moskva, Russia

Leonid Rapoport

Deputy Director
RI for Uronephrology, Sechenov University
Moscow, Moskva, Russia

Lubov Severgina

Sechenov University
Moscow, Moskva, Russia

Dmitry Enikeev

Deputy Director for Science
Institute for Urology and Reproductive health, Sechenov University
Moscow, Moskva, Russia

Surgical experience:
Experienced in TURP (>300 surgeries).
Experienced in upper urinary tract endosurgery (PCNL >200, RIRS >200).

2008-Present: Multiple upper and lower urinary tract surgeries;
2011-Present: HoLEP (400 surgeries);
2011-Present: En-bloc enucleation of bladder tumor (50 surgeries);
2016-Present: ThuLEP (>400 surgeries);
2016-Present: Thulium en-bloc enucleation of bladder tumor (>80 surgeries);
2016-Present: Brachytherapy (>40 surgeries); prostate cryoablation (70 surgeries), renal cancer cryoablation (30 surgeries);
Apr 2017-Present: Irreversible electroporation (10 surgeries);
Apr 2017-Present: MR-fusion prostate biopsy (80 procedures).

Nikolay Sorokin

Sechenov University
Moscow, Moskva, Russia

Dmitry Kislyakov

Sechenov University
Moscow, Moskva, Russia

Alexandra Proskura

Sechenov University
Moscow, Moskva, Russia