WCE 2018: Morphological Aspects of Laser (Thulium) En Bloc and Conventional Transurethral Resection of Bladder Cancer

Paris, France (UroToday.com) Thulium fiber laser technology is emerging new laser modality in prostate ablation. The primary advantage of these fiber lasers is their ability to deliver high energy from a relatively small fiber core. Thulium fiber lasers operate at wavelengths of 1,908 nm and 1,940 nm. These wavelengths match more closely with the water absorption peak than that of holmium lasers. This allows for much more precise resections of cancer. Dr. Dymov and his group looked at this laser and its utilization for en bloc resection of non-muscle invasive bladder cancer (NMIBC).

His primary objectives were to improve the morphological diagnostic criteria for NMIBC, compare the quality of specimen after thulium fiber laser resection and conventional transurethral resection of bladder tumor (cTURBT) methods, and finally to establish the important cooperation between uropathologists and surgeons.

There were 16 total procedures in the thulium fiber laser group and 10 for the conventional TURBT group. They utilized a Styrofoam fixation technique where the specimen was stretched over and pinned to a foam base (Figure 1). They also looked at T1a/T1b substaging (assessment of muscularis mucosa invasion) among other specific comparisons.

UroTodayWCE2018 Laser Thulium En Bloc and Conventional Transurethral Resection of Bladder Cancer
There was 100% T1a/T1b substaging in the thulium fiber group while only 30% possible substaging in the cTURBT group. The detrusor was present in 94% in the laser fiber group but only 60% in the cTURBT group. Moreover, there was less thermal damage of specimens in the thulium fiber group. The image below shows more of the comparisons that Dr. Dymov and his research team looked at. 

UroTodayWCE2018 Laser Thulium En Bloc and Conventional Transurethral Resection of Bladder Cancer 2
From this, we can see that there was a minimal coagulation of the tumor base and urothelium on resection margins and the absence of tumor mass coagulation. Moreover, when all layers are preserved from an intact specimen, this saves the differentiation from the tumor and its base.  Overall the thulium laser resection was more precise and allows for more enhanced evaluations of the lamina propria and muscularis propria invasion. This may allow for choosing a more correct treatment strategy in the future. One of the audience members asked about the cost-effectiveness of this procedure; however, the speaker said that the cost and cost-effectiveness will be assessed in the future.

Presented by Alim Dymov, Urologist, Sechenov University, Moscow, Moskva, Russia 
Co-Authors: 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, Nikolay Sorokin, Dmitry Kislyakov, and Alexandra Proskura, Sechenov University, Moscow, Moskva, Russia

Written by: John Sung, Department of Urology, University of California-Irvine, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France