The Safety and Efficacy of Vela Laser En-Bloc Endoscopic Resection versus Conventional Transurethral Resection of Bladder Tumor-A Single Center Experience

Experts' recommendations in laser use for the treatment of bladder cancer: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training and Research in Urological Surgery and Technology (TRUST)-Group

PURPOSE

To identify laser settings and limits applied by experts during laser vaporization (vapBT) and laser en-bloc resection of bladder tumors (ERBT) and to identify preventive measures to reduce complications.

METHODS

After a focused literature search to identify relevant questions, we conducted a survey (57 questions) which was sent to laser experts. The expert selection was based on clinical experience and scientific contribution. Participants were asked for used laser types, typical laser settings during specific scenarios, and preventive measures applied during surgery. Settings for a maximum of 2 different lasers for each scenario were possible. Responses and settings were compared among the reported laser types.

RESULTS

Twenty-three of 29 (79.3%) invited experts completed the survey. Thulium fiber laser (TFL) is the most common laser (57%), followed by Holmium:Yttrium-Aluminium-Garnet (Ho:YAG) (48%), continuous wave (cw) Thulium:Yttrium-Aluminium-Garnet (Tm:YAG) (26%), and pulsed Tm:YAG (13%). Experts prefer ERBT (91.3%) to vapBT (8.7%); however, relevant limitations such as tumor size, number, and anatomical tumor location exist. Laser settings were generally comparable; however, we could find significant differences between the laser sources for lateral wall ERBT (p = 0.028) and standard ERBT (p = 0.033), with cwTm:YAG and pulsed Tm:YAG being operated in higher power modes when compared to TFL and Ho:YAG. Experts prefer long pulse modes for Ho:YAG and short pulse modes for TFL lasers.

CONCLUSION

TFL seems to have replaced Ho:YAG and Tm:YAG. Most laser settings do not differ significantly among laser sources. For experts, continuous flow irrigation is the most commonly applied measure to reduce complications.

Predicting Preoperative Pathologic Grades of Bladder Cancer Using Intravoxel Incoherent Motion and Amide Proton Transfer-Weighted Imaging

RATIONALE AND OBJECTIVES

To investigate the predictive value of intravoxel incoherent motion (IVIM) combined with amide proton transfer-weighted (APTw) imaging for the preoperative grading of bladder cancer (BC).

MATERIALS AND METHODS

A total of 69 patients with histopathologically confirmed BC underwent diffusion-weighted imaging (DWI), IVIM, and APTw imaging at 3.0 T MRI. Two radiologists independently measured the mean apparent diffusion coefficient (ADC) in DWI, true diffusion coefficient (D), perfusion-related pseudo-diffusion coefficient (D*), and perfusion fraction (f) in IVIM, and APTw values, respectively. The areas under the receiver operating characteristic curves (AUCs) were utilized to compare the diagnostic efficacy of these single and combined quantitative parameters.

RESULTS

ADC and D values of low-grade BC were significantly higher than those of high-grade BC ([1.42 ± 0.20 ×10-3 mm2/s] vs. [1.09 ± 0.25 ×10-3 mm2/s] and [1.24 ± 0.24 ×10-3 mm2/s] vs. [0.89 ± 0.18 ×10-3 mm2/s], respectively; all P < 0.001). Opposite patterns were found for APTw ( [1.53 ± 0.42]% vs. [2.38 ± 0.71]%, P < 0.001). The ROC curves indicated that the combination of D and APTw values could distinguish low- from high-grades of BC with the highest predictive efficacy (AUC = 0.96), as well as a significant difference compared to those by ADC, D, and APTw values separately (AUC = 0.84, 0.88, 0.85, respectively; all P < 0.05).

CONCLUSION

IVIM combined with APTw imaging significantly improved the predictive efficacy of assessing low- and high-grade BC compared to the individual parameters on their own, providing an effective non-invasive method for clinical preoperative prediction of BC grading.

Precise diagnosis and treatment of non-muscle invasive bladder cancer - A clinical perspective

According to the guidelines, transurethral resection of bladder tumor (TURBT) followed by intravesical therapy remains the standard strategy for the management of non-muscle invasive bladder cancer (NMIBC). However, even if patients receive standard strategy, the risk of postoperative recurrence and progression is high. From the clinical perspective, the standard strategy needs to be optimized and improved. Compared to conventional TURBT, the technique of en bloc resection of bladder tumor (ERBT) removes the tumor tissue in one piece, thus following the principles of cancer surgery. Meanwhile, the integrity and spatial orientation of tumor tissue is protected during the operation, which is helpful for pathologists to make accurate histopathological analysis. Then, urologists can make a postoperative individualized treatment plan based on the patient's clinical characteristics and histopathological results. To date, there is no strong evidence that NMIBC patients treated with ERBT achieve better oncological prognosis, which indicates that ERBT alone does not yet improve patient outcomes. With the development of enhanced imaging technology and proteogenomics technology, en bloc resection combined with these technologies will make it possible to achieve precise diagnosis and treatment of bladder cancer. In this review, the authors analyze the current existing shortcomings of en bloc resection and points out its future direction, in order to promote continuous optimization of the management strategy of bladder cancer.