Utilization of imaging for staging in bladder cancer: is there a role for MRI or PET-computed tomography?

FDG-PET/CT for lymph node staging prior to radical cystectomy

BACKGROUND

¹⁸F-Fluorodeoxyglucose positron emission combined with computed tomography (FDG-PET/CT) has been proposed to improve preoperative staging in patients with bladder cancer subjected to radical cystectomy (RC).

OBJECTIVE

Our aim was to assess the accuracy of FDG-PET/CT for lymph node staging ascertained at the multidisciplinary tumour board compared to lymph node status in the surgical lymphadenectomy specimen obtained at RC, and to explore potential factors associated with false-positive FDG-PET/CT results.

DESIGN, SETTING AND PARTICIPANTS

Consecutive patients with bladder cancer undergoing RC with extended lymph node dissection between 2011 and 2019 without preoperative chemotherapy in a tertial referral cystectomy unit were included in the study.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSES

Sensitivity, specificity, positive and negative predictive values and likelihood ratios were calculated. Potential factors investigated for association with false-positive FDG-PET/CT were; bacteriuria within four weeks prior to FDG-PET/CT, Bacillus Calmette-Guerin (BCG) treatment within 12 months prior to FDG-PET/CT and transurethral resection of bladder tumour (TURB) within four weeks prior to FDG-PET/CT.

RESULTS

Among 157 patients included for analysis, 44 (28%) were clinically node positive according to FDG-PET/CT. The sensitivity and specificity for detection of lymph node metastasis were 50% and 84%, respectively, and the corresponding positive predictive and negative predictive values were 61% and 76%. Positive and negative likelihood ratios were 3.0 and 0.6, respectively. No association was found between bacteriuria, previous BCG treatment or TURB within 28 days and false-positive FDG-PET/CT results.

CONCLUSIONS

Preoperative FDG-PET/CT prior to RC had a clinically meaningful high specificity (84%) but lower sensitivity (50%) for detection of lymph node metastases compared to lymph node status in an extended pelvic lymphadenectomy template. We could not identify any factors associated with false-positive FDG-PET/CT outcomes.

The Safety and Efficacy of Vela Laser En-Bloc Endoscopic Resection versus Conventional Transurethral Resection of Bladder Tumor-A Single Center Experience

(1) Background: The current gold standard treatment of bladder cancer is conventional transurethral resection of the bladder tumor (CTURBT) using monopolar or bipolar resectoscopes. Laser en-bloc resection of the bladder tumor (LERBT) could achieve a higher quality of the specimen, reduce perioperative complications, and decrease the recurrence rate. Here, we compare the efficacy and safety of en-bloc Vela laser resection versus the conventional monopolar/bipolar resection; (2) Methods: A total of 100 clinically cT1-2 patients with bladder cancer were retrospectively reviewed in this study. Among these patients, 50 patients received LERBT, and 50 patients received CTURBT. The baseline characteristics, operation variables, and clinical outcomes were collected. The primary performance was the presence of muscle layer in the specimen. Perioperative complications and recurrence-free survival (RFS) were also compared. Independent t-test, Chi-square test, Kaplan–Meier curves, and the Cox-regression model were used in the analysis; (3) Results: The median age of the patients in the laser and resectoscope groups was 69.2 and 68.0 years old, respectively. The statistical difference in the presence of the detrusor muscle was 92.0% in the laser group and 70.0% in the CTURBT group (p = 0.005). A lower incidence of bladder perforation (p = 0.041) and major surgical complications (p = 0.046) in the LEBRT group was observed. We found no differences in operation duration, catheterization time, and hospitalization time after adjustment. Additionally, there was no statistical difference in RFS after a median follow-up time of 25 months; (4) Conclusions: Endoscopic laser en-bloc resection of bladder tumor with Vela laser is an effective method with higher muscle inclusion rate and fewer complications.

Advances in Transversal Topics Applicable to the Care of Bladder Cancer Patients in the Real-World Setting

Simple Summary

There are a number of scientific questions that are novel or controversial, which are clinically relevant in the real-world setting for patients diagnosed with bladder cancer, independently of the stage of disease or the histological type and grade of the tumors. These transversal topics have been discussed by a panel of expert specialists who participated in the Genitourinary Alliance Project, aimed to develop actions focused on the integration of relevant information into clinical practice. Advances in radiological imaging techniques have the potential of improving accuracy of staging methods, resulting in a more personalized planning and therapeutic option. The use of liquid biopsy will undoubtedly contribute to an increase in the efficiency of the evaluation of the clinical response and outcome of the disease. It is important to consider specific conditions of elderly people with bladder cancer, as well as the implementation of appropriate measures to enhance safe drug administration.

Abstract

Recommendations regarding transversal topics applicable to bladder cancer patients independent of tumor grade and stage were established by members of the Spanish Oncology Genitourinary Multidisciplinary Working Group (SOGUG). Liquid biopsy in urine and blood samples is useful in the surveillance of non-muscle-invasive and muscle-invasive bladder cancer, respectively. Multiparametric MRI is an accurate, faster and non-invasive staging method overcoming the understaging risk of other procedures. The combination of FDG-PET/MRI could improve diagnostic reliability, but definite criteria for imaging interpretation are still unclear. Hospital oncology pharmacists as members of tumor committees improve the safety of drug use. Additionally, safety recommendations during BCG preparation should be strictly followed. The initial evaluation of patients with bladder cancer should include a multidimensional geriatric assessment. Orthotopic neobladder reconstruction should be offered to motivated patients with full information of self-care requirements. Bladder-sparing protocols, including chemoradiation therapy and immune checkpoints inhibitors (ICIs), should be implemented in centers with well-coordinated multidisciplinary teams and offered to selected patients. The optimal strategy of treatment with ICIs should be defined from the initial diagnostic phase with indications based on scientific evidence. Centralized protocols combined with the experience of professional groups are needed for the integral care of bladder cancer patients.

Endoscopic Molecular Imaging plus Photoimmunotherapy: A New Strategy for Monitoring and Treatment of Bladder Cancer

Due to the high recurrence and progression rate of non-muscle invasive bladder cancer after transurethral resection of bladder tumor, some new optical imaging technologies have arisen as auxiliary imaging modes for white light cystoscopy to improve the detection rate of small or occult tumor lesions, such as photodynamic diagnosis, narrow-band imaging, and molecular imaging. White light cystoscopy is inadequate and imperfect for bladder cancer detection, and thus residual tumors or coexisting flat malignant lesions, especially carcinoma in situ, would be ignored during conventional resection. The bladder, a hollow organ with high compliance, provides an ideal closed operation darkroom for endoscopic molecular imaging free from interference of external light sources. Also, intravesical instillation of a molecular fluorescent tracer is simple and convenient before surgery through the urethra. Molecular fluorescent tracer has high sensitivity and specificity to tumor cells, and its mediated molecular imaging allows small or occult tumor lesion detection while minimizing false-positive results. Meanwhile, endoscopic molecular imaging provides a real-time and dynamic image during surgery, which helps urologists to perform high-quality and complete tumor resection through accurate judgment of tumor boundaries and depth of invasion. Photoimmunotherapy is a novel molecular targeted therapeutic pattern of photodynamic therapy that kills malignant cells selectively and minimizes the cytotoxicity to normal tissues. The combination of endoscopic molecular imaging and photoimmunotherapy used in initial treatment may avoid the need of repeat transurethral resection in strictly selected patients and improve oncological outcomes such as recurrence-free survival and overall survival after operation.