Multiparametic MRI may be beneficial for the detection, staging and follow-up of bladder cancer, according to an article published in the June issue of the American Journal of Roentgenology.
Although local and regional disease spread are the best predictors of treatment success in cases of urinary bladder cancer, a large discrepancy between preoperative clinical staging and final pathologic staging is common. “Clinical understaging occurs frequently, with higher risk of disease recurrence or death in this group of patients,” wrote the study’s lead author, Robbert J. de Haas, of the Radboud University Medical Center Nijmegen in the Netherlands, and colleagues. “Therefore, there is a need for advanced imaging tools, such as MRI, to optimize pre-operative staging and thereby improve treatment outcome.”
MRI is superior for the depiction of bladder cancer, as it clearly differentiates between muscle-invasive and muscle-noninvasive disease, a vital component of treatment planning. Recent advances in MRI technology hold even more promise for the diagnosis, local staging and posttreatment follow-up of urinary bladder cancer.
Multiparametric MRI, the combination of T1- and T2-weighted anatomic and functional sequences, could allow for better diagnosis of bladder cancer. However, the role of these techniques in detecting, localizing and staging has not yet been determined.
Several imaging modalities are currently used for the evaluation of bladder cancer. While ultrasound isn’t routinely used for this purpose, it is important in the initial analysis of hematuria. Ultrasound allows for the visualization of bladder tumors, but negative results don’t mean that bladder cancer is not present.
CT with urography is powerful in detecting upper and lower urinary tract lesions, and has been widely accepted as the preferred technique for staging urinary bladder cancer.
While 18F-FDG PET isn’t involved in the initial diagnosis of bladder cancer, it does play a role in staging and monitoring chemotherapy response. Because neoadjuvant chemotherapy is considered to be valuable in the treatment of urinary bladder cancer, restaging during and after chemotherapy is complete is increasingly important. FDG PET can evaluate metabolically active disease, but it doesn’t come without its issues. Urinary excretion of the radiotracer can interfere with staging and the impact of radiotherapy, endoscopic intervention and intravesical chemotherapy on FDG PET interpretation is unknown.
Cystoscopy is also used in patients with hematuria to evaluate the urinary bladder and urethral mucosa. Biopsy of suspicious bladder lesions is possible during cystoscopy and superficial bladder tumors can be resected during it as well.
At the present time, MRI is the best method for local and nodal staging of bladder cancer, according to the authors. Its main advantage comes from its ability to provide superior soft-tissue contrast without using radiation. The advent of multiparametric MRI shows promise, and its additional prognostic information could help guide effective treatment decisions.
“However, more adequately powered studies are needed to define the exact place of multiparametric MRI in bladder cancer patients,” wrote de Haas and colleagues.