ND: YAG nomogram dosimetry scale for the bladder

A retrospective comparison of thulium laser en bloc resection of bladder tumor and plasmakinetic transurethral resection of bladder tumor in primary non-muscle invasive bladder cancer

Bladder cancer is currently considered the most common malignancy of the urinary tract. Thulium laser en bloc resection of bladder tumor (TmLRBT) and plasmakinetic transurethral resection of bladder tumor (PK-TURBT) are two alternative common procedures used in our department to manage patients with primary non-muscle invasive bladder cancer (NMIBC) over the past decade. In this work, the safety and efficacy of TmLRBT were retrospectively compared to those of PK-TURBT in patients with primary NMIBC. From January 2013 to December 2015, 256 patients diagnosed with primary NMIBC were selected for this retrospective study. A total of 136 consecutive patients diagnosed with primary NMIBC were enrolled in the TmLRBT group. A similar historical cohort of 120 consecutive patients who underwent PK-TURBT was used to compare the two procedures. Clinical data, including age, gender, tumor characteristics, operation duration, hospitalization, irrigation, catheterization, and intraoperative and postoperative complications, were recorded. There were no significant differences in age, gender, mean tumor size, mean tumor number, tumor location, or risk between the TmLRBT and PK-TURBT groups. The TmLRBT group was associated with a significantly shorter operation duration (25.96 ± 21.19 min vs 37.18 ± 25.77 min, P = 0.018) and a shorter hospitalization time (3.11 ± 1.05 days vs 5.24 ± 2.06 days, P = 0.036). The postoperative irrigation time (6.33 ± 4.05 h vs 14.76 ± 6.28 h, P = 0.027) and catheterization time (2.03 ± 1.61 days vs 4.27 ± 1.17 days, P = 0.035) in the TmLRBT group were lower than those in the PK-TURBT group. No significant differences in fever and rebleeding were found in the TmLRBT and PK-TURBT groups. There were no significant differences in the overall, low-risk, intermediate-risk, and high-risk recurrence-free rates between the two groups (P = 0.43, P = 0.68, P = 0.71, and P = 0.24, respectively). The proportion of bladder detrusor muscle (BDM) identified in pathologic specimens of the TmLRBT group was higher than that in the PK-TURBT group (P = 0.006). TmLRBT may reduce operation duration time, hospitalization time, postoperative irrigation time, and catheterization time. TmLRBT is considered safer and more effective in treating primary NMIBC. Recurrence-free rates did not differ between groups.

Current evidence of transurethral Ho:YAG and Tm:YAG treatment of bladder cancer: update 2014

INTRODUCTION

Bladder cancer (BC) represents a growing health care problem worldwide. In times of tight budgets and an aging society, new strategies for the transurethral treatment of BC are needed. Laser devices used for tumor vaporization and/or en bloc resection provide an alternative to parvenu strategies.

MATERIALS AND METHODS

Medline/Cochrane search was performed using following terms: bladder cancer, urothelial carcinoma, laser, en bloc, vaporization, photoablation, holmium, thulium, Ho:YAG, Tm:YAG, HoLRBT and TmLRBT. Last date of search was February 12, 2014.

RESULTS

Eighteen publications in English were identified including 800 patients (Ho:YAG = 652 patients and Tm:YAG = 148 patients). Data on en bloc resection techniques were presented in 10 publications, 7 publications provided data of tumor vaporization and one publication presented data on both. Level of evidence based on SIGN is mainly 3 (non-analytic studies); only three studies are level 2 (prospective case control studies). Tumor vaporization seems to be a promising alternative for the treatment of recurrent tumors in selected patients. It can be performed in an office-based approach without the need of general anesthesia. The use of photodynamic diagnostic might enhance surgical quality. The principle of en bloc resection should provide accurate staging in most cases; however, data on this important aspect are missing. Peri- and postoperative complications are scarce. Due to the nature of the energy source, bladder perforation caused by obturator nerve reflex is highly unlikely when using lasers. There is a trend toward decreased infield recurrence rates.

CONCLUSIONS

Lasers are potentially useful alternatives to conventional TURBT, but systematical assessments using standardized classification systems and well-designed RCTs are needed to make results comparable.

Current evidence for transurethral laser therapy of non-muscle invasive bladder cancer

INTRODUCTION

Bladder cancer is the second most common malignancy of urologic tumors. Back in 1976, lasers were added to the endourological armetarium for bladder tumor treatment. Despite nowadays' standard procedure for staging and treating non-muscle invasive bladder tumor by transurethral resection of bladder tumors (TURB) via a wire loop, laser resection techniques for bladder tumor came back in focus with the introduction of Ho:YAG and not to mention recently Tm:YAG lasers. This review aims to display the current evidence for these techniques.

MATERIALS AND METHODS

Throughout April 2010, MEDLINE and the Cochrane central register of controlled trials were searched previously for the following terms: "Laser, resection, ablation, coagulation, Nd:YAG Neodym, HoYAG: Holmium, Tm:YAG Thulium and transitional carcinoma, bladder, intravesical."

RESULTS

Eleven articles on Ho:YAG and 7 on Tm:YAG were identified. Searches by Cochrane online library resulted in no available manuscripts.

CONCLUSION

Today, Nd:YAG does not play any role in treatment of lower urinary tract transitional cell carcinoma. Ho:YAG and Tm:YAG seem to offer alternatives in the treatment of bladder cancer, but still to prove their potential in larger prospective randomized controlled studies with long-term follow-up. Future expectations will show whether en bloc resection of tumors are preferable to the traditional "incise and scatter" resection technique, in which is contrary to all oncological surgical principles. For the primary targets, here are within first-time clearance of disease, in addition to low in-fields and out-of-fields recurrence rates.

Nd-YAG laser damage to metal and silicone endobronchial stents: delineation of margins of safety using an in vitro experimental model

STUDY OBJECTIVE

To identify margins of safety within which bronchoscopic Nd-YAG laser resection can be performed without damaging indwelling tracheobronchial stents.

DESIGN

Experimental in vitro study simulating a patient-care environment.

METHODS

Uncovered and covered metal Wallstent (Schneider; Zurich, Switzerland) and Dumon (Bryan Corporation; Woburn, MA) silicone stents were deployed in the tracheobronchial tree of a ventilated and oxygenated (fraction of inspired oxygen, 40%) heart-lung block of a dead canine. Rigid bronchoscopic Nd-YAG (1,064 nm) laser procedures were performed in order to deliver laser energy using fiber-to-target distances of 10 mm and 20 mm, and noncontact, continuous-mode, 1-s pulses at power settings of 10 W, 30 W, and 40 W. The major outcome measure was laser-induced stent damage, defined as discoloration, ignition, or breakage. This was assessed using six power densities: 75 W/cm(2), 172 W/cm(2), 225 W/cm(2), 300 W/cm(2), 518 W/cm(2), and 690 W/cm(2).

RESULTS

The uncovered Wallstent and the silicone stent remained intact at power densities of 75 W/cm(2) (10 W, 20 mm) and 172 W/cm(2) (10 W, 10 mm), but were damaged at power densities > 225 W/cm(2) (30 W, 20 mm). The covered Wallstent was damaged at all power densities tested.

CONCLUSION

Uncovered Wallstent and silicone stents are not damaged when Nd-YAG laser energy is delivered using power densities < or = 72 W/cm(2) (10 W, 10 mm). Covered Wallstents, however, had a high likelihood of ignition at all power densities studied.

Is the neodymium:YAG laser effective therapy for invasive bladder cancer?

The neodymium:YAG (yttrium-aluminum-garnet) laser can cause transmural coagulation necrosis of bladder tumor or bladder wall. Pathologic specimens of 18 patients prospectively treated with the neodymium:YAG laser before radical cystectomy were reviewed to compare the initial clinical stage of bladder tumor with the final pathologic stage and to assess the destructive tissue effects of neodymium:YAG laser therapy. Eleven of 18 patients were unchanged pathologically in stage of tumor or had tumor progression. Seven patients had a lower pathologic tumor stage; 3 of these patients had pathologic Stage T0 with no residual tumor, with the remainder of patients showing superficial disease. One asymptomatic small bowel injury was discovered at operation. Healing lesions showed marked granulation tissue, coagulation necrosis, and persistent ulceration.

Transurethral ultrasound-guided laser-induced prostatectomy (TULIP procedure): a canine prostate feasibility study

We describe the TULIP procedure, a new system to relieve bladder outlet obstruction caused by benign prostatic hyperplasia. This device is composed of a real-time 7.5 MHz ultrasound transducer coupled to a Nd:YAG laser with a 1.064 microns wavelength that fires through an intact intraprostatic balloon. A series of feasibility studies in 21 canine prostate glands was performed with a follow-up time to 3 months. Results indicate that the Nd:YAG laser in the 20 to 40 W range at a pull rate of approximately 1 mm. per second is an effective means of removing substantial amounts of canine benign prostatic hyperplasia. Transurethral ultrasonography was a reliable means of identifying essential landmarks and of controlling the laser. Prostatectomy by laser coagulation necrosis resulted in no bleeding or postoperative obstruction. Intraoperative irrigation fluids were not required, eliminating systemic volume related problems.