The incidence of bladder cancer is increasing year by year, and surgery is its main treatment strategy. Until today, ERBT technology has been widely accepted by clinicians. In addition, a variety of ERBT technologies have been invented8–9. However, ERBT does not have a definite standard. Moreover, its efficacy with traditional TURBT is also controversial. At present, random comparison of ERBT with needle electrode and traditional TURBT is rare in clinic.
Our approach based on propensity score matching directly compared the therapeutic benefits of ERBT and traditional TURBT. After 1:1 matching, there was no statistically significant difference in the recurrence rate between the two groups (P = 0.226). One study suggested that ERBT can avoid tumor fragmentation, thereby minimize the floating of tumor cells, reducing the risk of recurrence of tumors4. However, we did not find that ERBT showed an advantage in terms of recurrence rate and progression rate. This is consistent with the results of some literature published in recent years. Zhang et al10 compared 90 patients with NMIBC treated by transurethral resection of bladder tumors (40 in the ERBT group and 50 in the traditional TURBT group), and found that there was no difference in the total recurrence rate between the two groups (20% vs 24%, P = 0.650). In addition, a study11 compared ERBT with 1.9 microm vela laser and traditional TURBT, and there was no difference in recurrence rate between the two groups (P > 0.05). However, an randomized controlled trial 12 believes that although the recurrence rate at the same location is similar in the ERBT group and the TURBT group (4.9% vs 7.5%, P > 0.05), the ERBT group has a clear advantage in terms of overall recurrence rate ( 17.1% vs 27.5%, P<0.05). Therefore, in terms of recurrence rate, whether ERBT can achieve better efficacy than the traditional TURBT group requires more experiments to prove. In terms of progression rate, this study found that although the results of the two groups were not statistically different, when the factor of tumor grade was limited, the difference in progression rate between the two groups was significantly reduced. It can be seen that tumor grade seems to be a factor affecting tumor progression.
In terms of surgical effect, we compared the effects of two different surgical methods on operation time, intraoperative hemorrhage, intraoperative complications, postoperative fart time, bladder irrigation time, and catheterization time, etc. The results showed that the ERBT group had an advantage in intraoperative bleeding compared with the traditional TURBT group (P = 0.04). We believe that during the ERBT operation, the tumor is usually removed from the surrounding tumor and advanced to the root of the tumor, so that the blood vessels around the tumor can be cut off and hemostasis can be stopped in time, which allows a better visual field during surgery and bleeding Also less. In the study by Balan et al12, compared with the traditional TURBT group, the ERBT group had a lower drop in hemoglobin (0.28 vs 0.76 g/dL, P < 0.05). It can be seen that ERBT does have an advantage in improving intraoperative bleeding. Some articles reported that ERBT can effectively reduce the time of flushing, catheterization and hospitalization12–14, but in our study, no differences were found between the two groups. In terms of surgery time, some studies believe that ERBT takes less time (13.4 vs 19.7 min, P < 0.05)12, and some studies find that ERBT takes longer surgery time (40.0 vs 19.5 min, P = 0.0002)13. In our opinion, the operation time is mainly related to the experience of the surgeon doctor and the surgical instruments used. In this study, the surgeon doctor has extensive experience in surgery. At the same time, we use needle electrodes as a resection tool, which has a small contact surface with the tissue, which effectively reduces the time spent adjusting the position. Of course, the small contact area will slow the rate of resection, therefore, we did not find a difference in surgical time between the two groups. After PSM matching, we found that there were no surgical complications in the two groups of patients. Analyzing the data before matching, there was no difference in obturator nerve reflex between the two groups. This seems to be contrary to some research results12, 15. However, reading of the relevant literature carefully reveals that the traditional TURBT energy source in this type of research is a plasma monopolar source, while our traditional TURBT group energy source is a plasma bipolar electrode. In theory, the use of bipolar energy can reduce the risk of obturator nerve reflexes. Avallone et al16 compared the safety and efficacy of monopolar and bipolar energy TURBT in the treatment of NMIBC, and found that the use of bipolar energy has a tendency to reduce obturator nerve reflexes (2.6% vs 5.8%).
Research suggests that the presence of detrusor muscles is an important surgical quality control indicator used to indicate complete tumor resection17. The results of Zhang et al10 showed that the presence of detrusor muscle was easier to find in the pathological tissue after ERBT (100% vs 54%, P < 0.01). Another study also recognized the advantages of ERBT in this regard (2.94% vs 20.0%, P = 0.04)18. In this study, we also found that the pathological tissue after ERBT seems to be easier to find the detrusor muscle (100% vs 90.9%), however, statistical analysis did not find a difference between the two groups. In our analysis, this may be due to the fact that the two surgical procedures in this study both excised the tissue from the surgical wound and left it as the base specimen, which can effectively find the detrusor muscle. Comparing the postoperative pathological results of the two groups, ERBT can obtain higher-quality tumor specimens, especially less burn marks on the muscle layer, which is very beneficial for postoperative evaluation of the depth of tumor invasion.
In multivariate analysis, we found that tumor grade and tumor size are risk factors affecting tumor recurrence rate, which may be due to two factors related to postoperative tumor residuals. The EAU guidelines suggest that patients with high-grade bladder cancer have a higher risk of residual tumor after surgery1. Yuk et al19 analyzed the risk factors affecting the residual tumor after TURBT by univariate and multivariate analysis methods. The results showed that the high-grade tumors (1.925 [1.014–3.656], P = 0.045) and tumors ≥ 3 cm (2.56 [1.13–6.04], P = 0.026) were independent risk factors for tumor residuals.
In this study, when performing ERBT on a large bladder tumor, how to completely remove the tumor is a puzzling thing. Most studies currently use 3 cm as the upper limit of ERBT. For tumors that are too large, we divide them 2–3 times and then take them out. Studies have suggested that fragmentation of tumor tissue can affect the pathological results of the tumor and underestimate the stage of the tumor. and in the process of tumors cutting, cancer cells are prone to grow and metastasize, which leads to recurrence4. Hayashida et al20 proposed a new scheme combining endoscopic mucosal resection (EMR) and ERBT. EMR is used to remove the part of the tumor that protrudes from the mucosa, and use ERBT to remove the remaining part. And compare the recurrence rate of this surgical method with traditional TURBT. The results showed that there was no difference in the recurrence rate between the two groups (P = 0.662). In addition, the postoperative pathology of the new surgery can determine the degree of infiltration, while 19.4% of patients in the traditional group cannot determine the degree of infiltration (P = 0.016). Therefore, it seems to be a feasible method to segment tumor samples properly.