Retrograde en bloc resection for non-muscle invasive bladder tumor can reduce the risk of seeding cancer cells into the peripheral circulation

En bloc resection of large bladder tumor: is it feasible and reasonable?

PURPOSE OF REVIEW

Transurethral resection of bladder tumor (TURBT) remains the basis of bladder tumor diagnosis and an effective means of treating nonmuscle invasive bladder cancer (NMIBC). There are several limitations to this procedure: TURBT may cause free floating of malignant cells in the bladder and as a result re-implantation and early recurrence. Also, it does not allow the pathologist to define the correct spatial orientation of the specimen. The development of en bloc resection of bladder tumor (ERBT) has helped overcome the abovementioned key disadvantages of TURBT. However, many urologists doubt whether this approach is feasible for treating larger tumors.

RECENT FINDINGS

In this review, it is shown that ERBT of large bladder tumor (>3 cm) is in fact a feasible and well tolerated method. Although there is a lack of comparative data proving its advantages over TURBT, en bloc in large tumor seems to result in better local cancer control (due to higher prevalence of detrusor specimen, lower need for re-TURBT), lower rate of relapse outside the resection area (due to lower risk of tumor cells circulation), and higher quality of pathology specimen.

SUMMARY

Despite the skepticism of some surgeons, potential difficulties caused by larger tumor size may be overcome easily, and most agree that tumor size should not limit the implementation of the method in their daily practice.

Current opinions regarding the clinical utility of en bloc resection in the treatment of non-muscle invasive bladder cancer-a review of the literature

Non-muscle invasive bladder cancer (NMIBC) is currently mainly treated with the approach of transurethral resection of bladder tumor (TURBT) followed by pathology investigation of the obtained specimens. However, this approach-TURBT-has a few drawbacks, owing to the inherent technical defect-"piecemeal" resection. With development of medical science and surgical techniques, a new kind of surgical operation-"en bloc" resection of bladder tumor (ERBT)-emerged, hoping to completely remove bladder tumor with surrounding normal tissue. The detrusor muscle layer beneath the tumor is removed, and the surgical quality of bladder tumor is enhanced, with a better pathological outcome, reduced intraoperative complications and lower recurrence rate eventually. This paper reviews current literature concerning a brief history of ERBT developing, surgical steps, its indications, advantages on surgical margin, recurrence during follow-up, pathological performance-presence of detrusor muscle, residual tumor and upstage, as well as such issue as "is reTURBT necessary after ERBT?" and the guiding significance of ERBT in substaging of T1 bladder cancer.

Transurethral Resection of Bladder Tumor: Novel Techniques in a New Era

Transurethral resection of bladder tumor (TURBT) serves both diagnostic and therapeutic purposes in the management of bladder cancer. Attaining a high-quality TURBT is not always guaranteed due to various factors. En-bloc resection of bladder tumors (ERBT) holds promise to be a primary technique for removing bladder tumors in most non-muscle invasive bladder cancers. However, so far, no conclusive evidence indicates the superiority of any specific energy source used for ERBT. While laser energy can prevent the activation of obturator nerve reflex during ERBT, it poses challenges such as thermal injury and imprecise controllability. Needle-shaped electrodes offer high-level precision and controllability, without causing tissue deterioration or vaporization. The primary limitation of ERBT at present is the extraction/harvesting of large en-bloc specimens. Effective tools have been developed to overcome this limitation. Enhanced cystoscopy improves the detection of flat and small bladder tumors, allowing for better removal of cancerous tissues and significantly reducing recurrence rates. Advances in medical technology have brought forth a multitude of strategies to address the shortcomings of traditional TURBT. Appliances with large operating channel provide a platform for conducting laparoscopic procedures within the context of pneumocystoscopy, facilitating the execution of super TURBT and conferring comparable advantages to en-bloc resection. Moreover, the utilization of pneumocystoscopy enables the safe and effective performance of transurethral partial cystectomy for localized muscle-invasive bladder cancer. Novel techniques significantly improve the precision of the transurethral surgery and lower the risk of complications.

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.

Distant metastasis without regional progression in non-muscle invasive bladder cancer: case report and pooled analysis of literature

Background

Non-muscle invasive bladder cancer (NMIBC) represents the majority of bladder neoplasms. It is unusual for NMIBC metastasizing distantly without regional progression, namely metastatic NMIBC (mNMIBC), which is still poorly understood and easily omitted based on current management policies. So far, description of mNMIBC is limited to a few case reports.

Methods

We reported a 70-year-old man with NMIBC who suffered from cervical metastasis without pelvic recurrence at 41 months after initial diagnosis. Then we performed a collective analysis of this case together with published mNMIBC cases searched from PubMed, Embase, and Web of Science, aiming to illustrate baseline clinicopathologic parameters, metastatic patterns, and treatment outcomes of these patients and analyze associated influencing factors.

Results

After scrupulous review, 45 cases previous reported and the one from our center were incorporated into the aggregated cohort of mNMIBC, including 34 males and 12 females. Primary tumors from 46.7% of patients were high-grade (HG) or grade 3 (G3) and 65.1% had T1 lesions. Aberrant biomarker expression was found in tumors of some cases. Most (40/46) metastases of mNMIBC occurred at a single site, mainly in lung, bone and lymph nodes. Apart from three cases of de novo mNMIBC, the mean metastasis-free survival (MFS) interval of metachronous mNMIBC was 42.5 months, which was obviously longer than conventional metastatic bladder cancer. Shortened MFS interval was associated with old age, T1 or HG/G3 primary tumors, and non-lung metastases. Systemic chemotherapy and metastasectomy or radiotherapy for oligometastatic lesion were main therapeutic approaches of mNMIBC, and immunotherapy was adopted for the case from our center. Lung and bone metastases correlated with relatively favorable and unfavorable survival outcomes, respectively. Compared with monotherapy, chemotherapy, or immunotherapy combined with local cytoreduction got more favorable outcomes.

Conclusion

Although rare, mNMIBC occurs more in tumors with high-risk features. Usually, mNMIBC metastasizes later than conventional metastatic bladder cancer and manifests as solitary lesion. Outcomes of mNMIBC would be influenced by metastatic site and post-metastatic treatment. Systemic treatment combined with local cytoreduction may render survival benefit in selected patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02664-5.

En Bloc Resection of Bladder Tumor-Is It the Way Forward?

Transurethral resection of bladder tumors (TURBT) represents the cornerstone in diagnosis and treatment of bladder cancer but recurrence is observed in up to 80% and over- or understaging with TURBT is common. A more recent development to overcome these limitations represents en-bloc resection of bladder tumors (ERBT) which offers several advantages over TURBT. In this report, we briefly review studies assessing outcomes of bladder cancer patients undergoing ERBT. Most randomized and non-randomized trial demonstrate improvement in clinical outcomes for ERBT over TURBT, however more pathological and translational studies are warranted.

Systemic dissemination of tumor cells during transurethral resection in patients with bladder tumor and its clinical relevance: A follow up study

OBJECTIVE

Tumor cells are shed during transurethral resection of bladder tumor (TURBT) and form the basis for use of single dose immediate chemotherapy instillation to reduce recurrences. Systemic dissemination of these cells along with the irrigation fluid is also possible but not consistently proven. In this study, we evaluated such dissemination of tumor cells into the circulation during TURBT and its clinical impact.

METHODS

Patients with primary presentation of bladder tumor who underwent TURBT were included. Peripheral venous blood samples before and after TURBT were analyzed for circulating tumor cells (CTCs) using flow-cytometry. A CD45 negative cell with positive expression of cytokeratin 18, 19, and EpCam was defined as CTC. The CTC counts, pre and post TURBT, were compared and correlated with final histopathology. The patients were also followed up for any local and/or systemic recurrences.

RESULTS

Nine (16.98%) out of 53 patients developed a measurable rise in CTCs after TURBT. All of these patients had high grade and muscle invasive disease. Overall, a measurable rise in CTCs was seen in 9 out of 17 (52.94%) patients with muscle invasive disease. There was no difference in the clinico-pathological stage or the status of cystectomy and/or chemotherapy between those who did or did not show a rise in CTCs. On follow up, 7 patients with muscle invasive disease developed local and/or systemic recurrences and the rise in CTCs was not found to be associated with adverse oncological outcomes.

CONCLUSIONS

This study confirms the hypothesis of inadvertent dissemination of tumor cells into the circulation during TURBT, especially in patients with high grade and muscle invasive disease. The long-term oncological impact of such dissemination remains to be confirmed.

En Bloc Tumor Resection, Optical Molecular Imaging, and the Potential Synergy of the Combination of the Two Techniques in Bladder Cancer

Although transurethral resection of bladder tumor is the golden standard for the treatment of non-muscle invasive bladder cancer, this surgical procedure still has some serious drawbacks. For example, piecemeal resection of tumor tissue results in exfoliated tumor cells dissemination and implantation, and fragmented tumor specimens make it difficult for pathologists to accurately assess the pathological stage and histologic grade. En bloc tumor resection follows the basic principle of oncological surgery and provides an intact tumor specimen containing detrusor muscle for pathologists to make accurate histopathological assessment. However, there is no robust clinical evidence that en bloc tumor resection is superior to conventional resection in terms of oncological outcomes. Considering the high recurrence rate, small or occult tumor lesions may be overlooked and incomplete tumor resection may occur during white light cystoscopy-assisted transurethral resection. Molecular fluorescent tracers have the ability to bind tumor cells with high sensitivity and specificity. Optical molecular imaging mediated by it can detect small or occult malignant lesions while minimizing the occurrence of false-positive results. Meanwhile, optical molecular imaging can provide dynamic and real-time image guidance in the surgical procedure, which helps urologists to accurately determine the boundary and depth of tumor invasion, so as to perform complete and high-quality transurethral tumor resection. Integrating the advantages of these two technologies, optical molecular imaging-assisted en bloc tumor resection shows the potential to improve the positive detection rate of small or occult tumor lesions and the quality of transurethral resection, resulting in high recurrence-free and progression-free survival rates.

Transurethral en bloc resection with monopolar current for non-muscle invasive bladder cancer based on TNM system

Background

To evaluate the surgical safety and quality of transurethral en bloc resection with monopolar current for non-muscle invasive bladder cancer (NMIBC) based on the tumour, node, metastasis (TNM) classification system, and report the midterm oncological outcome.

Methods

From October 2015 to June 2017, en bloc resection of bladder tumor (ERBT) and transurethral resection of bladder tumor (TURBT) were performed in 96 and 87 patients clinically diagnosed with NMIBC in the prospective case-control trial, respectively. Operative details, intraoperative and postoperative complications regarded as safety outcomes were documented. The quality of ERBT was judged by the histopathological examination of tumor specimens from initial resection and second TURBT, random bladder biopsy and follow-up recurrence rate.

Results

Operative time, obturator nerve reflex, irrigation and catheterization time were similar in the two groups. Bladder perforation was occurred in 2 patients during ERBT and 9 patients during TURBT (2/96 vs. 9/87, P=0.019). Compared with TURBT group, the ratio of detrusor muscle (DM) identified in pathologic T1 tumor specimens was higher (P=0.024), but lower in pathologic Ta tumor specimens in ERBT group (P<0.001). The residual tumor identified in ERBT group was lower than that in TURBT group during second TURBT (2/28 vs. 10/32, P=0.020). The recurrence-free survival rate did not differ significantly between the two groups after 24 months follow-up.

Conclusions

ERBT based on TNM system is a safe and feasible technique to treat patients with NMIBC. Besides, ERBT may reduce the proportion of bladder perforation and residual tumor during initial resection.