Bladder tumor ablation with 980-nm and 980-/1470-nm diode lasers: a retrospective study

In 2023, the American Cancer Society estimates that there will be approximately 82,290 new cases of bladder cancer in the USA, with approximately 62,420 occurring in men and 19,870 in women. Furthermore, it is projected that there will be about 16,710 deaths resulting from bladder cancer, including roughly 12,160 in men and 4550 in women [1]. An estimated 74,000 new bladder cancer patients were diagnosed in 2015, of which approximately 75% were non-muscle invasive types, with a higher incidence among younger patients [2]. Endourological treatments such as transurethral resection of bladder tumors are often prescribed based on the guidelines set forth by several countries [3]. The efficacy of diode laser technology, such as the 980-nm and 980-/1470-nm systems, in bladder tumor ablation is of considerable interest because of its capacity to minimize complications compared with conventional TURBT. Previous studies have suggested that laser en bloc resection may be superior to conventional TURBT in terms of diminished complication and recurrence rates. Moreover, the precise tumor stage and grade obtained through laser en bloc resection can provide further insight into the effectiveness of this form of treatment [4, 5]. The use of true holmium (Ho:YAG) or thulium (Tm:YAG) lasers has also been reported to be safe, effective, and minimally invasive for treating bladder tumors [6]. The 1470-nm/980-nm dual-wavelength laser technique is a relatively new development that offers a wealth of benefits [7]. Resection and vaporization can be carried out quickly with the 1470-nm section, while hemostasis may be achieved efficiently and without contact via the 980-nm component [8]. As such, this technology is very attractive for medical applications. A study has recently demonstrated that it can also be employed safely and effectively for vascular lesions [9]. A diode laser with a wavelength of 980 nm has demonstrated good results in hemostasis and ablation [10].

This study aimed to explore the safety and feasibility of both single- and dual-wavelength diode lasers (980 nm and 980/1470 nm) in the ablation of bladder tumors of any type followed for minimum of 12 months.

The mean age of 151 (male = 115 and female = 36) patients was 64.72 ± 13.85 years with 65/151 (43%) above age of 75 years. The mean size of the tumors was 4.88 ± 2.16 cm (Table 1). Among 151 patients, 31 (20.52%) had diabetes mellitus, 19 (12.58%) had hypertension, and 49% had tumors on the left lateral wall of the bladder (Figs. 2, 3). Furthermore, 115/151 (76%) and 31/151 (20.5%) patients experienced mild and moderate discomfort postoperatively, respectively, and no blood transfusions were necessary during the procedure in any case. Postoperatively, histopathology showed 92/151 (60.9%) low-grade and 53/151 (35%) high-grade tumors, and 06/151 (4%) were not recognized. The procedure was also a success, with no conversions required to TURBT, as well as an ablation/coagulation time of 1.57 ± 0.73 h, 15.33 ± 3.93 h’s irrigation and 6.58 ± 1.47 days of catheterization in all 151 patients post-surgery. In 3/151 (2.98%) patients, secondary bleeding was reported. After surgery, 09/151 (5.96%) patients' urine color was not clear and they were managed conservatively. There were no cases of recurrence reported at ablation sites in the following 12-month postoperative follow-up in both muscle invasive or non-muscle invasive bladder tumors. However, growths were seen at margins of previously ablated sites in 12/151 (7.94%). Twenty-one out of 151 patients (13.90%) developed urinary tract infections after surgery (Table 2). Overall, diode lasers with ablation technique have proved to be highly beneficial for tumors located in difficult sites including diverticula bladder tumors, with little to no difficulty.

TURBT, the conventional method of treating NMIBCs, is associated with a heightened risk of possible complications, such as obturator nerve reflex and postoperative bleeding, in turn increasing the odds of malignancy and recurrence [11, 12]. The same issue has yet to be addressed using V-LABT. While some reported outcomes suggest that bipolar resection may lessen the complications risk compared with resection of bladder tumors with monopolar, these results are inconclusive [13, 14]. In our cases, we discovered a reduced possibility of recurrence on ablation sites and complications.

Staehler et al. first reported the use of lasers for urological surgery, and since then, it has become popular for prostate and bladder procedures. Tey described a technique of transurethral ablation of bladder tumors using an Nd:YAG laser [15, 16]. A 980-nm diode laser was tested and found to be effective in treating NMIBC in vitro [17]. In clinical practice, other lasers, such as the thulium laser, the holmium laser, the 2-μm laser, and the 1.9-μm vela laser, have all been proved safe and effective [18‐21]. While resecting tumors from the lateral walls of the bladder, an electric current can flow through the obturator nerve, causing a potential bladder perforation and OBR during TURBT [22]. However, in our cases, no obturator reflex was observed, as no current was used directly. With Holmium lasers, cutting is reported to be precise with efficient hemostasis [23]. In our series, we observed that diode lasers have much better hemostatic properties than holmium lasers. Moreover, in cases of brisk bleeding from a spurter, we had to help with the ball electrode. Only one patient with a huge tumor required post-op clot evacuation. It has been suggested that around 30% of individuals cannot receive ERBT due to the size, shape, or location of their tumors [24]. Tumors located at the anterior and posterior bladder walls, bladder neck, or exceeding 3 cm in size are usually avoided in such cases. This was not a factor for exclusion in this study; even though a majority of the tumors were on the lateral walls, there were 35 cases located on the dome and trigone as well as on the bladder neck. Despite this, all tumors were treated successfully with an ablation technique. It has been concluded that TULA with diode laser is a safe and well-tolerated procedure [25].

Currently, there exists a limited amount of research regarding the utilization of 980-nm and 980-/1470-nm diode lasers for the ablation of bladder tumors. However, in this particular study, a total of 151 patients who were diagnosed with bladder tumors of any type underwent an innovative procedure involving the ablation/coagulation of the bladder tumor using either 980-nm or 980-/1470-nm diode lasers. We did our best to avoid complications of heat injury, often beginning by coagulating the tumor stalk first before ablation or coagulation of the rest of its growth. Cases involving large or multiple tumors were ablated as much as possible and then waited for two months before performing another cystoscopy to determine whether fresh tissue had grown or the scab remained adherent to the site of ablation. This process was repeated, depending on the results.

Almost always after ablating/coagulating a tumor, we resect the tumor partially (more safe) and allow the necrotic tissue to shed itself in due course. As a result of the efficient hemostasis achieved by the diode laser, these benefits, namely low postoperative clot formation, reduced bladder irrigation requirements, and less postoperative bladder discomfort, are all related. As a result of its potent hemostatic property, the diode laser provides a bloodless surgical field.

Our study has certain limitations that should be considered. Firstly, its retrospective nature and small sample size reduce the generalizability of our findings. Additionally, our investigation solely focused on patients treated by a single surgeon, which may limit the applicability of our results to a broader population. The method in which patients were enrolled could have introduced selection bias, potentially affecting the validity of our conclusions. Moreover, since all patients' data were grouped together, we were unable to make a direct comparison between single-wavelength and dual-wavelength lasers. Consequently, it is crucial that future research includes a prospective design to address these limitations and provide more comprehensive insights into the topic.

The utilization of both the 980-nm and 980-/1470-nm diode lasers for transurethral ablation of bladder tumors through the ablation technique proves to be effective, efficient, and safe. The findings of using single- and dual-wavelength diode lasers for ablating bladder tumors are encouraging. These lasers demonstrate excellent hemostatic properties and have shown satisfactory postoperative outcomes followed for at least 1 year. This study opens up pathways for further research on the utilization of diode lasers through ablation technique in the future. In order to validate our promising short-term outcomes, it is imperative to conduct prospective randomized controlled trials that incorporate extensive long-term follow-up.