Thulium:YAG Versus Holmium:YAG Laser Effect on Upper Urinary Tract Soft Tissue: Evidence from an Ex Vivo Experimental Study

Laser-Induced Blood Coagulation for Surgical Application: A Scoping Review

There is a lack of evidence-based reviews on the effects of laser irradiation on blood coagulation in the literature, despite a large number of clinical trials. We therefore evaluated the available evidence on laser irradiation parameters used in coagulation of blood to optimize physical parameters. We performed a literature search for recent scientific studies indexed between 2017 and 2023 using the databases of PubMed and ScienceDirect. Articles were selected based on defined inclusion and exclusion criteria, and 78 publications in total were eventually included in this scoping review. The following were found to produce significant benefits in blood coagulation for surgical application: (1) dentistry and oral surgeries: 980 nm, 27 s, 2 W, 1502.7 W/cm2, 26.5 J, 622 J/cm2, 400 μm; (2) urogenital disorders: 532 nm, 4 s, 40 W, 10600 W/cm2, 1.3 J, 424 J/cm2, 600 μm; (3) ophthalmic disorders: 810 nm, 1 s, 1 W, 3540 W/cm2, 0.75 J, 1326 J/cm2, 100 μm; (4) embryological surgeries: 1064 nm, 10 s, 25 W, 35400 W/cm2, 262.5 J, 371000 J/cm2, 332.5 μm; (5) dermatological disorders: 1064 nm, 20 W, 2440 W/cm2, 0.1 J, 24 J/cm2, 670 μm; (6) gastrointestinal disorders: 532 nm, 3 s, 20 W, 1051 W/cm2, 120 J, 26500 J/cm2, 760 μm; (7) neurological surgeries: 2.5 s, 1.5 W, 1035 W/cm2, 2 J, 1584 J/cm2, 385 μm; (8) pulmonary disorders: 1320 nm, 5s, 35 W, 12450 W/cm2, 250 J, 65000 J/cm2, 700 μm (9) cardiovascular disorders: 1064 nm, 16.5 s, 5 W, 1980.5 W/cm2, 900 J, 760 J/cm2, 400 μm. In conclusion, our scoping review identifies that combining data from all clinically heterogeneous studies suggests that laser irradiation reflects an effective method for inducing blood coagulation in several medical fields.

450-nm blue diode laser: a novel medical apparatus for upper tract urothelial lesions

OBJECTIVE

To explore the feasibility, safety and effectiveness of the 450-nm blue diode laser (BL), novel blue laser in the treatment of upper tract urothelial carcinomas (UTUCs) and other lesions in a porcine model.

MATERIAL AND METHODS

For in vitro experiment, the ureter tissue was vaporised and coagulated with BL, green-light laser (GL) and Ho:YAG laser (Ho). The efficiency, width and depth of vaporisation, and depth of coagulation were recorded and compared. For in vivo experiments, four swines weighing 70 kg were used. In the acute group, different modes of operations were performed to evaluate the thermal damage, perforation and bleeding. In the chronic group, the overall appearance of the ureter and laser wound healing were observed by the naked eyes and H&E staining 3 weeks after surgery.

RESULTS

In in vitro study, the BL showed a higher efficiency of tissue vaporisation and less tissue coagulation for fresh ureter compared to GL and Ho. In the in vivo study, the power of BL set at 7 W was better, and the thickness of thermal damage varied with different surgery types in the range of 74-306 μm. After 3 weeks, the wound healed well static in vaporisation (SV), moving vaporisation (MV) and H&E staining indicated mucosal healing rather than scar healing.

CONCLUSION

5-10W blue diode laser achieved a higher efficiency of tissue vaporisation and less tissue coagulation in a porcine model, indicating its potential application in the endoscopic surgery of UTUC as an optional device with high performance and safety.

What to expect from the novel pulsed thulium:YAG laser? A systematic review of endourological applications

INTRODUCTION

Several preclinical studies about a novel pulsed-thulium:yttrium-aluminum-garnet (p-Tm:YAG) device have been published, demonstrating its possible clinical relevance.

METHODS

We systematically reviewed the reality and expectations for this new p-Tm:YAG technology. A PubMed, Scopus and Embase search were performed. All relevant studies and data identified in the bibliographic search were selected, categorized, and summarized.

RESULTS

Tm:YAG is a solid state diode-pumped laser that emits at a wavelength of 2013 nm, in the infrared spectrum. Despite being close to the Ho:YAG emission wavelength (2120 nm), Tm:YAG is much closer to the water absorption peak and has higher absorption coefficient in liquid water. At present, there very few evaluations of the commercially available p-Tm:YAG devices. There is a lack of information on how the technical aspects, functionality and pulse mechanism can be maximized for clinical utility. Available preclinical studies suggest that p-Tm:YAG laser may potentially increase the ablated stone weight as compared to Ho:YAG under specific condition and similar laser parameters, showing lower retropulsion as well. Regarding laser safety, a preclinical study observed similar absolute temperature and cumulative equivalent minutes at 43° C as compared to Ho:YAG. Finally, laser-associated soft-tissue damage was assessed at histological level, showing similar extent of alterations due to coagulation and necrosis when compared with the other clinically relevant lasers.

CONCLUSIONS

The p-Tm:YAG appears to be a potential alternative to the Ho:YAG and TFL according to these preliminary laboratory data. Due to its novelty, further studies are needed to broaden our understanding of its functioning and clinical applicability.

Histopathological assessment of depth of coagulation necrosis with Holmium, Moses, and Thulium fiber lasers in human prostate tissue

PURPOSE

To evaluate coagulation necrosis depth (CND) of Holmium (HL), Moses (ML), and Thulium fiber laser (TFL) in ex vivo human prostate tissue at various energy settings.

METHODS

After endoscopic HL enucleation, small prostate tissue fragments were removed from the bladder with graspers and used for study. Immediately after surgery, a single incision was made on the surface of the tissue kept under normal saline at room temperature using a hand-held 550-µm laser fiber. Variable energy settings were tested for all three lasers. Two pathologists measured the CND with light microscopy using ocular micrometer. Impact of various laser settings on CND was analyzed. The differences in CND of all three lasers at similar laser power were compared.

RESULTS

Mean CND was 0.56 ± 0.53 mm for long-pulse HL, 0.54 ± 0.53 mm for ML, 0.67 ± 0.67 mm for low-pulse TFL, and 0.81 ± 0.78 mm for high-pulse TFL. There was no significant difference between mean CND of HL and ML at various laser settings ranging from 10 to 120 W and CND with long- and short-pulse settings of TFL at settings from 10 to 60 W. There was a trend of increasing CND in HL and ML with increasing laser power; however, it was not statistically significant. TFL had similar tissue effects as HL and ML.

CONCLUSION

There is no significant difference in CND of HL, ML, and TFL in ex vivo human prostate tissue. Other factors besides laser type and settings need to be studied to explain clinical differences among various lasers used for prostate enucleation.

Experts' recommendations in laser use for the treatment of upper tract urothelial carcinoma: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training Research in Urological Surgery and Technology (T.R.U.S.T.) group

PURPOSE

To highlight and compare experts' laser settings during endoscopic laser treatment of upper tract urothelial carcinoma (UTUC), to identify measures to reduce complications, and to propose guidance for endourologists.

METHODS

Following a focused literature search to identify relevant questions, a survey was sent to laser experts. We asked participants for typical settings during specific scenarios (ureteroscopy (URS), retrograde intrarenal surgery (RIRS), and percutaneous treatment). These settings were compared among the reported laser types to find common settings and limits. Additionally, we identified preventive measures commonly applied during surgery.

RESULTS

Twenty experts completed the survey, needing a mean time of 12.7 min. Overall, most common laser type was Holmium-Yttrium-Aluminum-Garnet (Ho:YAG) (70%, 14/20) followed by Thulium fiber laser (TFL) (45%, 9/20), pulsed Thulium-Yttrium-Aluminum-Garnet (Tm:YAG) (3/20, 15%), and continuous wave (cw)Tm:YAG (1/20, 5%). Pulse energy for the treatment of distal ureteral tumors was significantly different with median settings of 0.9 J, 1 J and 0.45 J for Ho:YAG, TFL and pulsed Tm:YAG, respectively (p = 0.048). During URS and RIRS, pulse shapes were significantly different, with Ho:YAG being used in long pulse and TFL in short pulse mode (all p < 0.05). We did not find further disparities.

CONCLUSION

Ho:YAG is used by most experts, while TFL is the most promising alternative. Laser settings largely do not vary significantly. However, further research with novel lasers is necessary to define the optimal approach. With the recent introduction of small caliber and more flexible scopes, minimal-invasive UTUC treatment is further undergoing an extension of applicability in appropriately selected patients.

Modern Kidney-Sparing Management of Upper Tract Urothelial Carcinoma

PURPOSE

To review the latest evidence on the modern techniques and outcomes of kidney-sparing surgeries (KSS) in patients with upper tract urothelial carcinoma (UTUC).

METHODS

A comprehensive literature search on the study topic was conducted before 30 April 2023 using electronic databases including PubMed, MEDLINE, and EMBASE. A narrative overview of the literature was then provided based on the extracted data and a qualitative synthesis of the findings.

RESULTS

KSS is recommended for low- as well as select high-risk UTUCs who are not eligible for radical treatments. Endoscopic ablation is a KSS option that is associated with similar oncological outcomes compared with radical treatments while preserving renal function in well-selected patients. The other option in this setting is distal ureterectomy, which has the advantage of providing a definitive pathological stage and grade. Data from retrospective studies support the superiority of this approach over radical treatment with similar oncological outcomes, albeit in select cases. Novel chemoablation agents have also been studied in the past few years, of which mitomycin gel has received FDA approval for use in low-risk UTUCs.

CONCLUSION

KSSs are acceptable approaches for patients with low- and select high-risk UTUCs, which preserve renal function without compromising the oncological outcomes.

Learning from the past and present to change the future: Endoscopic management of upper urinary tract urothelial carcinoma

Current guidelines recommend endoscopic management (EM) for patients with low-risk upper urinary tract urothelial carcinoma, as well as those with an imperative indication. However, regardless of the tumor risk, radical nephroureterectomy is still mainly performed worldwide despite the benefits of EM, such as renal function maintenance, no hemodialysis requirement, and treatment cost reduction. This might be explained by the association of EM with a high risk of local recurrence and progression. Furthermore, the need for rigorous patient selection and close surveillance following EM may be relevant. Nevertheless, recent developments in diagnostic modalities, pathological evaluation, surgical devices and techniques, and intracavitary regimens have been reported, which may contribute to improved risk stratification and treatments with superior oncological outcomes. In this review, considering recent advances in endourology and oncology, we propose novel treatment strategies for optimal EM.

Endoscopic Conservative Treatment of Upper Urinary Tract Urothelial Carcinoma with a Thulium Laser: A Systematic Review

INTRODUCTION

Thulium lasers (TLs), namely the Thulium fiber laser (TFL) and the Thulium:YAG (Tm:YAG), are being increasingly adopted for the conservative treatment of upper urinary tract urothelial carcinoma (UTUC). However, to date, the real clinical impact of TLs on UTUC management remains not well-characterized. We performed a review of the literature to summarize the current evidence on TLs for UTUC treatment.

MATERIALS AND METHODS

We performed a systematic review in January 2023 using the Embase and Medline online databases, according to the PRISMA recommendations and using the PICO criteria. Outcomes of interest were: (i) to assess the safety and feasibility of TLs in the treatment of UTUC, and (ii) to evaluate the oncological outcomes in terms of tumor recurrence and conservative treatment failure. Moreover, we described TL characteristics and its interaction with soft tissue.

RESULTS

a total of 458 articles were screened, and six full texts including 273 patients were identified. All the included studies were retrospective series. Mean patient age ranged from 66 to 73 years. The indication of a conservative treatment was elective and imperative in 21.7-85% and 15-76% of cases, respectively. Laser power settings varied from 5 to 50 W. No intraoperative complications were reported, and all the procedures were successfully performed. The tumor recurrence rate was 17.7-44%, and the indication to radical nephroureterectomy was 3.7-44% during a follow-up of 6-50 months. Most of the postoperative complications were mild and transient, and ureteral strictures were reported in two studies. Major limitations were the retrospective nature of the studies, the small sample sizes, and the short follow-up.

CONCLUSIONS

TL is an effective and safe technology for endoscopic UTUC treatment. However, current available literature lacks prospective and multicentric studies with large population sizes and long-term follow-up.

Strategies of Endoscopic Management of Upper Tract Urothelial Carcinoma among Endourologists: A Global Survey

Up-to-date guidelines on the management of upper tract urothelial carcinoma (UTUC) are continuously published. We aim to assess the variability of diagnosis and treatment strategies in the endoscopic management of UTUC and adherence to European Association of Urology and National Comprehensive Cancer Network guidelines. A 15-question survey was designed to query practitioners on approaches to clinical practice and knowledge about endoscopic treatment indications and techniques. It was emailed to all members of the Endourologic Society through the society’s office, and to all Israeli non-member endourologists. Eighty-eight urologists participated in the survey. Adherence to guidelines on indications for endoscopic management was only 51%. Most of the survey respondents (87.5%) use holmium laser for tumor ablation, and ~50% use forceps for biopsy while the other half use baskets. Only 50% stated that they would use Jelmyto® for specific indications. Most (80%) indicated that they repeat the ureteroscopy 3 months after the first one, and 52.3% continue with follow-up ureteroscopy every 3 months during the first year after diagnosis. There is vast variability among endourologists in the technical aspects of UTUC, the indications for endoscopic management, and adherence to the available guidelines for managing UTUC.

A Review of How Lasers Are Used in UTUC Surgery: Can the Choice of Laser Affect Outcomes?

Upper tract urothelial carcinoma (UTUC) is a relatively rare disease with an aggressive phenotype compared to urothelial carcinoma in the bladder. In recent years, kidney-sparing surgery (KSS) and, in particular, endoscopic surgery have become the procedure of choice among urologists where the treatment of localized UTUC is concerned. Endoscopy tends to result in satisfactory oncological disease control while lowering morbidity and minimizing complications amongst the appropriately selected cohort of patients. While endoscopic surgery for UTUC might appear to be standardized, it, in fact, differs considerably depending on the source of energy used for resection/ablation. There has been little reliable data up to now on which laser energy source is the most superior. The goal of this review is, therefore, to outline the results of endoscopic UTUC treatment using different lasers and to analyze how these laser-tissue interactions may affect the surgery. We start by pointing out that the data remains insufficient when trying to determine which laser is the most effective in the endoscopic management of UTUC. The ever-growing number of indications for minimally invasive treatment and the increasing number of centers using laser surgery will, hopefully, lead to novel randomized controlled trials that compare the performance characteristics of the lasers as well as the effects of UTUC on patients.

Current laser therapy options for endoscopic treatment of upper tract urothelial carcinoma

Endoscopic management via retrograde ureteroscopic laser ablation of upper tract urothelial carcinoma (UTUC) has become the preferred treatment modality for low-risk tumors. The most popular ablative lasers over the past 15-20 years have been the holmium:yttrium-aluminum-garnet (Ho:YAG) and neodymium (Nd:YAG) lasers, but recently the thulium (Th:YAG) laser has emerged as a potential alternative. This review compares the mechanism of action, physiological properties and effects, and oncologic outcomes of Ho:YAG/Nd:YAG lasers versus the Th:YAG laser for UTUC treatment. Potential advantages of the Th:YAG laser over existing technologies are outlined, followed by a discussion of emerging laser technologies in UTUC management.

Tissue thermal effect during lithotripsy and tissue ablation in endourology: a systematic review of experimental studies comparing Holmium and Thulium lasers

PURPOSE

We looked into the Thulium: yttrium-aluminum-garnet (TM:YAG), Thulium Fibre laser (TFL) and Holmium: yttrium-aluminum-garnet (Ho:YAG) thermal laser tissue effect during lithotripsy and tissue ablation.

METHODS

We performed a PubMed, Scopus, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) search.

RESULTS

During lithotripsy, the Ho:YAG generated temperatures from 24 to 68.7 °C at powers < 20 W, the Tm:YAG from 43.7 °C at 30 W to 68 °C at powers < 20 W, and the TFL from 33 to 40.46 °C. During ablation, the Ho:YAG and continuous wave (cw) Tm:YAG tissue incision depths ranged from 0.08 to 2.26 mm, and from 0.28 to 3.22 mm. The Ho:YAG and Tm:YAG vaporization areas ranged from 0.044 to 0.078 mm² and from 0.050 to 0.078 mm³ and their coagulation zones were 0.075 mm² and 0.125 mm³ respectively. Ho:YAG and Tm:YAG laser damage zones ranged from 0.093 to 2.6 mm³ and from 0.207 to 0.98 mm³ respectively. The TFL incision depth ranged from 0.04 to 5.7 mm. The cw and SuperPulsed (SP) vaporization volumes ranged from 8 to 28.2 mm³/s and from 4 to 11 mm³/s. TFL coagulation depth and coagulation zone ranged from zero to 1.1 mm, 2.2 to 5.1 mm³ in SP mode and from 7.7 to 18.1 mm³ in cw mode.

CONCLUSION

During lithotripsy all lasers caused similar temperature changes and had a safe temperature profile at < 40 W. During tissue ablation, Ho:YAG has a deeper incision depth, while cwTm:YAG and cwTFL have broader coagulation and total laser areas.

Effectiveness and Safety of Thulium Fiber Laser in the Conservative Management of Patients with Upper Tract Urothelial Carcinoma

Background

Few clinical data are available on thulium fiber laser (TFL) and conservative treatment of upper urinary tract urothelial carcinoma (UTUC).

Objective

To assess the effectiveness and safety of TFL in the conservative treatment of UTUC in terms of both tumor ablation and complication rates in a short-term follow-up.

Design setting and participants

Retrospective data were collected from all patients who underwent endoscopic management of UTUC between January 2021 and April 2022. All patients with nonmetastatic UTUC who were deemed suitable candidates (low- and high-grade disease) for conservative treatment were reviewed.

Intervention

All patients underwent ureteroscopy with biopsy and at 2, 6, and 12 mo after the first surgery. UTUC ablation was achieved using TFL.

Outcome measurements and statistical analysis

Clinical data were collected in a dedicated database. Intra- and postoperative outcomes were assessed. A descriptive statistical analysis was performed.

Results and limitations

In total, 28 patients were evaluated. Thirteen patients (46.4%) were included in the low-risk UTUC treatment group and 15 (53.6%) in the high-risk group. The mean tumor size was 15.3 ± 5.7 mm. Biopsy showed low- and high-grade UTUCs in 19 and eight patients, respectively. Only one biopsy was inconclusive for achieving a diagnosis. At the second procedure biopsy, no tumor was found in 19 cases (70.4%), whereas seven had tumors confirmed (25.9%). To date, 23 and 17 out of 26 patients completed the 6- and 12-mo follow-up, respectively. UTUC recurrence was detected in five of 23 patients (21.7%) and in three of 17 patients (17.7%) at 6 and 12 mo, respectively. A total of 95 procedures were performed. No intraoperative complications were observed. In ten of the 95 procedures (10.5%), Clavien-Dindo grade I-II postoperative complications were experienced. Only one grade IIIB postoperative complication was noted.

Conclusions

TFL is a safe and effective technique for conservative treatment of UTUC in a short-term follow-up. Optimal tumor ablation and fine hemostatic control were achieved without major complications.

Patient summary

In this study, we looked at the outcomes of upper urinary tract tumors conservatively treated with the new thulium fiber laser (TFL). We conclude that TFL represents a safe and effective technique for the treatment of this kind of tumors in a short-term follow-up.

The role of endoscopic management and adjuvant topical therapy for upper tract urothelial cancer

Upper tract urothelial carcinoma (UTUC) has traditionally been managed with radical nephroureterectomy, and while this approach remains the gold standard for high-risk disease, endoscopic, kidney-sparing management has increasingly been adopted for low-risk disease as it preserves kidney function without compromising oncologic outcomes. Ureteroscopy and percutaneous renal access not only provide diagnoses by tumor visualization and biopsy, but also enable treatment with electrocautery or laser ablation. Several modalities exist for laser ablative treatments including thulium:YAG, neodymium:YAG, holmium:YAG, and combinations of the preceding. Furthermore, due to high recurrence rates after endoscopic management, adjuvant intracavitary instillation of various agents such as mitomycin C and bacillus Calmette-Guerin have been used given benefits seen in non-muscle invasive urothelial bladder cancer. Other formulations also being studied include gemcitabine, anthracyclines, and immunotherapies. More recently, Jelmyto, a mitomycin reverse thermal gel, has been developed to allow for adequate drug delivery time and potency since urine flow could otherwise dilute and washout topical therapy. In this article, the authors review techniques, indications, best practices, and areas of current investigation in endoscopic management and adjuvant topical therapy for UTUC.

Laser technology in urologic oncology

Laser technology has been used in Urology since the 80s with a lot of different applications in endoscopic and open surgery. With the developments of the technology and the introduction of new active medium and source of laser energy, this technology have become the gold standard not only in stone surgery but even in benign prostate enlargement (BPE) surgical treatment. Regarding urologic oncology, laser energy has now reached an important role in focal therapy and in conservative treatment. The possibility of having better functional outcomes without any relevant impact on oncological results led to an increased use of laser in penile surgery, with a significant mention in urological guidelines for this option. In urothelial cancers as well, both in conservative management of upper tract tumors that in the treatment of non muscle invasive bladder cancer, a clear role of these relatively new source of energy have been demonstrated. Finally, both in prostate that in renal cancer the strategy of focal therapy may take advantage from this precise and fine technology. In this review we analyzed and described the applications of laser energy in urological cancers with a specific focus on penile, urothelial and prostate cancer.

Successful endoscopic treatment using thulium YAG laser for multiple ureteral fibroepithelial polyps in a pediatric patient

Introduction

Ureteral fibroepithelial polyps are extremely rare and cause ureteropelvic junction obstruction in the pediatric population. Recent advancements in endoscopic treatment, such as holmium:yttrium–aluminum–garnet laser, have created more options for practitioners to treat multiple ureteral fibroepithelial polyps cases. However, the use of holmium:yttrium–aluminum–garnet laser multilobulated ureteral fibroepithelial polyps may have technical difficulties.

Case presentation

An 11‐year‐old boy with intermittent right flank pain revealed multiple ureteral fibroepithelial polyps approximately 3 cm long at the right ureteropelvic junction. The ureteral fibroepithelial polyps were resected using flexible ureteroscopy using thulium:YAG laser. A second‐look ureteroscopy revealed no recurrence, residual polyps, or ureteral stricture. At 1‐year follow‐up, ultrasonography showed no hydronephrosis on the affected side.

Conclusion

Thulium:YAG laser provides clear visibility due to its high hemostatic and evaporation effects. To the best of our knowledge, this is the first pediatric case of multiple ureteral fibroepithelial polyps successfully treated with endoscopic resection using thulium:YAG laser, with a favorable clinical outcome.

New Lasers for Stone Treatment

Laser technology has been a breakthrough in urology. The new era in endocorporeal laser lithotripsy has recently begun in mid-2020, where promising technologies tested in vitro have reached their approval for clinical use and, in that way, have made it possible to confirm their safety and advantages in the real world, for the patient and for the urologist.

Comparison of Holmium:YAG and Thulium Fiber lasers on soft tissue : an ex vivo study

OBJECTIVE

To assess the fiber-tissue interaction through ablation, coagulation, and carbonization characteristics of the Ho:YAG laser and Super Pulsed Thulium Fiber Laser (TFL) in a non-perfused porcine kidney model. To assess the degradation of laser fibers during soft tissue treatment.

METHODS

A 50W TFL generator was compared to a 120W Ho:YAG laser. The laser settings that can be set identically between the two lasers (pulse energy and frequency), and clinically relevant for prostate laser enucleation, were identified and used for tissue incisions on fresh non-frozen porcine kidneys. For each parameter were also tested the short, medium and long pulse durations for the Ho:YAG generator, and the different peak powers 150W, 250W and 500W for the TFL. Laser incisions were performed with 550μm stripped laser fiber fixed on a robotic arm at a distance of 0.1mm with the tissue surface and at a constant speed of 10mm/s. Histological analysis was then performed, evaluating: incision shape, incision depth and width, axial coagulation depth, presence of carbonization. Degradation of the laser fiber was defined as reduction of laser fiber tip length after laser activation.

RESULTS

Incision depths and areas of coagulation were greater with the Ho:YAG laser compared to the TFL. While no carbonization zone was found with the Ho:YAG laser, this was constant with the TFL. While a fiber tip degradation was constantly observed with Ho:YAG laser, except in the case of a long pulse duration and low pulse energy (0.2J), this was not the case with TFL.

CONCLUSION

TFL appears to be an efficient alternative to Ho:YAG laser for soft tissue surgery. The histological analysis found greater tissue penetration with the Ho:YAG laser and different coagulation properties between the two lasers. These results need to be investigated in vivo to assess the clinical impact of these differences and find the optimal settings for laser prostate enucleation.

Photodynamic Diagnosis-guided Dual Laser Ablation for Upper Urinary Tract Carcinoma: Preoperative Preparation, Surgical Technique, and Clinical Outcomes

Background

Although ureteroscopic surgery (URS) is beneficial for low-risk upper urinary tract carcinoma (UTUC), there is no standardized URS technique or navigation system for challenging cases.

Objective

To present a URS technique for UTUC using thulium (Tm):YAG and holmium (Ho):YAG lasers under photodynamic diagnosis (PDD) guidance, named PDD-guided dual laser ablation (PDD-DLA) and compare its efficacy with that of conventional Ho:YAG laser ablation (HLA; historical control).

Design, setting, and participants

The study included ten consecutive UTUC patients who underwent PDD-DLA between 2017 and 2019. The control group comprised 16 consecutive patients who underwent HLA between 2006 and 2016.

Surgical procedure

After oral administration of 5-aminolevulinic acid (20 mg/kg), UTUC tumors were endoscopically resected via PDD-DLA.

Measurements

Clinical data were prospectively collected for our institutional UTUC data set. Disease progression, UTUC recurrence, and clinical outcomes were assessed.

Results and limitations

PDD-DLA was successfully performed in all patients. The median tumor size was 23.5 mm (interquartile range [IQR] 12.8–30.0) and there were four cases (40.0%) of high-grade tumor. The median operative time was 120 min (IQR 98.5–142.5). No Clavien-Dindo grade ≥3 complications were observed. There were no differences in most clinical characteristics between the PDD-DLA and HLA groups. The 2-yr progression-free survival rate was 100% in the PDD-DLA group and 58.7% in the HLA group (p = 0.0197), and the 2-yr recurrence-free survival rate was 57.1% and 41.3%, respectively (p = 0.072). The PDD-DLA group had a lower incidence rate of salvage RNU compared with the HLA group (0.0% vs 50%; p = 0.009). The small sample size might affect the reproducibility of these results.

Conclusions

PDD-DLA seems to be an effective and feasible endoscopic technique for UTUC treatment with favorable oncological outcomes.

Patient summary

We investigated a new laser technique for treating cancer of the upper urinary tract called photodynamic diagnosis–guided dual laser ablation. Our strategy was effective in removing tumors and stopping bleeding. Further studies in larger groups of patients are needed to confirm whether this technique improves cancer outcomes.