Staging bladder cancer

Intravesical Contrast-Enhanced MRI: A Potential Tool for Bladder Cancer Surveillance and Staging

This review article gives an overview of the current state of the art of bladder cancer imaging and then discusses in depth the scientific and technical merit of a novel imaging approach, tracing its evolution from murine cancer models to cancer patients. While the poor resolution of soft tissue obtained by widely available imaging options such as abdominal sonography and radiation-based CT leaves them only suitable for measuring the gross tumor volume and bladder wall thickening, dynamic contrast-enhanced magnetic resolution imaging (DCE MRI) is demonstrably superior in resolving muscle invasion. However, major barriers still exist in its adoption. Instead of injection for DCE-MRI, intravesical contrast-enhanced MRI (ICE-MRI) instills Gadolinium chelate (Gadobutrol) together with trace amounts of superparamagnetic agents for measurement of tumor volume, depth, and aggressiveness. ICE-MRI leverages leaky tight junctions to accelerate passive paracellular diffusion of Gadobutrol (604.71 Daltons) by treading the paracellular ingress pathway of fluorescein sodium and of mitomycin (<400 Daltons) into bladder tumor. The soaring cost of diagnosis and care of bladder cancer could be mitigated by reducing the use of expensive operating room resources with a potential non-surgical imaging option for cancer surveillance, thereby reducing over-diagnosis and over-treatment and increasing organ preservation.

Role of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Staging of Bladder Cancer

INTRODUCTION

Dynamic Contrast Enhanced (DCE)-Magnetic Resonance Imaging (MRI) is a useful technique in which rapid enhancement of tumour by uptake of the contrast agent compared to bladder wall.

AIM

To evaluate the accuracy of dynamic gadolinium-enhanced MRI in staging of bladder cancer through differentiating superficial tumours from invasive tumours and organ-confined tumours from non-organ-confined tumours. In addition, the benefits of DCE-MRI in diagnosis of tumour progression steps were investigated.

MATERIALS AND METHODS

This was a quasi-experimental study in which 45 patients (95.55% men and 4.45% women) were enrolled. Patients with confirmed transitional cell carcinoma by histopathology findings were imaged using 1.5 Tesla MRI systems. Pathology results were considered as the standard reference. Tumour stage was determined by imaging findings and compared with pathologic findings after radical cystectomy. Data were analysed by SPSS version 16 and the level of significance in all tests was considered p<0.001.

RESULTS

The most common stage that was seen in pathology and MRI findings was T3b. Kappa agreement coefficient between MRI and pathology was 0.7 (p<0.001). The accuracy of MRI in differentiating superficial tumours (≤T1) from invasive tumours (≥ T2a), and organ-confined tumours (≤T2b) from non-organ-confined tumours (≥T3b) was 0.97 and 0.84, respectively. The overall accuracy of MRI was 0.77 (p<0.001). Totally, 10 cases of disagreement between MRI and pathological staging were found, eight (80%) of which were overestimated and two cases (20%) underestimated. MRI detection rate was 0% in stage Ta, 100% in stage T1, 66.7% in stage T2, 86.7% in stage T3, and 100% in stage T4. The sensitivity and specificity of MRI in differentiating superficial tumours from invasive tumours were 0.97 and 1, respectively, and in differentiating organ-confined tumours from non-organ-confined tumours were 0.94 and 0.77, respectively. The Spearman's correlation coefficient between the signal enhancement slope of time-intensity curves and tumour stages was 0.88 (p<0.001).

CONCLUSION

Gadolinium-enhanced MRI is an appropriate and useful modality with a high accuracy in determining the stage of the bladder cancer. In addition, this method shows extension and progression of tumour and tumour invasion depth.

A new parameter for staging bladder carcinoma: ultrasonographic contact length and height-to-length ratio

OBJECTIVE

The purpose of this study was to investigate the value of tumor-bladder wall contact length (CL), tumor height (H), and height-to-length ratio (H/CL) for preoperative staging of bladder carcinoma.

METHODS

Fifty-seven patients with bladder tumors underwent suprapubic ultrasonography preoperatively, and the CL of the tumor with the bladder wall and H in the bladder lumen were measured. The CL, H, and H/CL values were correlated with the wall invasion determined by histopathologic analysis of the cystectomy material. Invasion was staged according to the TNM classification system.

RESULTS

Statistically significant differences were found for CL (P < .001) and H/CL (P = .001) between the superficial and invasive tumor groups. These parameters were also effective for differentiating superficial or deep muscle invasion. A CL of greater than 41.5 mm and an H/CL of less than 0.605 were calculated as cutoff values for differentiating superficial and invasive tumors. Height had no value for determining invasion.

CONCLUSIONS

The ultrasonographic measurements of CL of the tumor with the bladder wall and H/CL may be useful for staging bladder carcinoma by verification of these findings in larger groups of patients.

Bladder Cancer: Analysis of Multi–Detector Row Helical CT Enhancement Pattern and Accuracy in Tumor Detection and Perivesical Staging

PURPOSE

To evaluate the enhancement pattern of bladder cancer and the accuracy of multi-detector row helical computed tomography (CT) in the detection and staging of bladder cancer.

MATERIALS AND METHODS

In 20 patients, the attenuation value of bladder cancer was measured on dynamic contrast material-enhanced multiphasic CT images obtained with scanning delays of 40, 60, 80, and 100 seconds. In 67 patients, CT data were obtained with a 60-second scanning delay that covered the bladder (section thickness, 2.5 mm; beam pitch, 1.5) and a 180-second scanning delay that covered the abdomen (section thickness, 5 mm; beam pitch, 1.5). We prospectively evaluated CT images and compared findings at CT with findings at histologic examination. We evaluated cancer detection rate, positive predictive value of cancer detection, and sensitivity and specificity in the diagnosis of perivesical invasion.

RESULTS

The attenuation value of bladder cancers was significantly higher on 60- (105 HU +/- 16) and 80-second (97 HU +/- 15) delayed CT images than on the other images (P <.05). The cancer detection rate and positive predictive value for cancer detection were 97% and 95%, respectively, in 67 patients and increased to 100% and 100%, respectively, in 44 patients with a time interval of 7 or more days between transurethral resection of the bladder (TURB) and CT examination. Sensitivity and specificity in the diagnosis of perivesical invasion were 89% and 95%, respectively, in 67 patients and increased to 92% and 98%, respectively, in 44 patients with a time interval of 7 or more days between TURB and CT examination.

CONCLUSION

Bladder cancer tends to show peak enhancement with the 60-second scanning delay. Multi-detector row helical CT is useful in the detection and staging of bladder cancer.

MR imaging of the bladder

MR imaging of the bladder can now be routinely and easily performed with consistent quality. The latest techniques provide high-resolution images of the soft tissue contrast and the ability to perform dynamic contrast imaging and functional pelvic floor studies. MR imaging fits in as a complimentary tool to cystoscopy and to conventional pelvic floor dynamic studies and can provide a unique imaging perspective of the bladder. It is important, however, to remain cognizant of the limitations of its use in tumor detection and discrimination.

MR evaluation of normal retroperitoneal and pelvic lymph nodes

PURPOSE

To establish guidelines for normal retroperitoneal and pelvic lymph node size at magnetic resonance imaging (MRI) by correlation with computed tomographic (CT) and lymphangiographic (LAG) data.

MATERIALS AND METHODS

Twelve patients previously studied with pre- and post-LAG CT to determine normal pelvic lymph node size [ 1 ] were examined with MRI. All were on surveillance for stage I testicular tumour (minimum follow-up 10 years). Three observers recorded blind the site, size and number of nodes in the retroperitoneum and pelvis at 11 sites. The results were validated with previous CT imaging.

RESULTS

Eight hundred and fifteen nodes in 12 patients were visible on the MRI initially, and a further 44 nodes were identified after comparison with post-LAG CT. More nodes were seen on MRI than on CT. The 95th centile values for maximum short axis diameter (MSAD) of pelvic lymph nodes were common iliac and obturator 4 mm, external and internal iliac 5 mm and hypogastric 6 mm. In the retroperitoneum the 95th centile MSAD values were retrocrural, high left para-aortic, paracaval and interaortocaval 3 mm, post-caval 4 mm and low left para-aortic 5 mm.

CONCLUSION

MRI criteria for normal retroperitoneal and pelvic lymph node size are defined. Adoption of these recommendations may improve the sensitivity of MRI for the detection of nodal metastases.

Ultrasonographic analysis of bladder tumors

To analyze the ultrasonographic features of bladder tumors during transabdominal ultrasonography. Ultrasonograms of consecutive patients diagnosed to have bladder tumors from August 1992 to May 1999 were reviewed retrospectively and correlated with the final histological diagnoses. Various features, including the location, size, multiplicity, shape, surface and presence of calcification, of the bladder tumors were analyzed. Of 109 patients reviewed, 104 had transitional cell carcinoma, 3 adenocarcinoma, 1 carcinosarcoma and 1 prostatic carcinoma. A total of 130 tumors (including 13 multifocal tumors) were detected with 30 (27.5%) patients having more than one tumor in the bladder. Tumor size ranged from 0.5 to 9.7 cm (mean 2.7 cm). The tumor involved the trigone (63, 48.5%), lateral wall (32, 24.6%), posterior wall (17, 13.1%), anterior wall (5, 3.8%) or was multifocal (13, 10%). Sixty-seven (51.5%) tumors were polypoidal, 47 (36.2%) were sessile and 16 (12.3%) plaque-like. The surface was regular in 50 (38.5%) tumors and irregular in 80 (61.5%) tumors. Calcified foci were noted in 54 (41.5%) tumors. There was no statistically significant correlation between ultrasonographic features. The most common appearance is a polypoid lesion arising from the trigone, but there was much variation in the ultrasonographic features of bladder tumors.

MR imaging of carcinoma within urinary bladder diverticulum

Cystoendoscopic examination and standard radiological techniques occasionally fail to correctly establish that a pelvic mass is due to carcinoma arising within a urinary bladder diverticulum. MR imaging in oblique planes can facilitate the diagnosis in such cases by demonstrating the neck of the diverticulum. Also, T2-weighted images allow differentiation between tumor within a diverticulum and a necrotic extravesical mass.

Evaluation of effect of treatment for invasive bladder cancer by ultrasonography with intra-arterial infusion of carbon dioxide microbubbles

RATIONALE AND OBJECTIVES

The purpose of this study was to evaluate the diagnostic usefulness of the ultrasonography with intra-arterial infusion of carbon dioxide microbubbles (CO2) for invasive bladder cancer.

METHODS

Twelve patients with muscle-invading bladder cancer who were treated by concurrent radiotherapy and intra-arterial infusion of daily low dose of cisplatin using an implanted infusion port were included. A total of 30 studies was performed during the treatment to evaluate the visualization of the tumor and effect of the treatment compared with conventional ultrasonography, computed tomography, or cystoscopy.

RESULTS

Satisfactory visualization of the tumor in CO2 ultrasonography was obtained in all patients, in particular in those with flat tumor or prostatic invasion. The enhancement effect of CO2 on the tumor, which was maintained well in the late period of the treatment, made possible evaluation of the therapeutic effect. With respect to the evaluation of local response, disagreement between clinical response and the evaluation of CO2 ultrasonography was observed in two patients with definite differentiation between wall edema and residual tumor after treatment being difficult.

CONCLUSIONS

Carbon dioxide ultrasonography is easy to perform in patients treated with arterial infusion therapy using an implanted infusion port and provides practical information in evaluating therapeutic effect.

Staging of bladder cancer

The definitive diagnosis of bladder cancer is established at cystoscopic examination and confirmed by means of a transurethral biopsy. A careful bimanual palpation of the bladder under anesthesia is an integral part of the initial assessment of each patient. The most important part of the assessment of patients with bladder cancer is a thorough pathologic examination of the biopsy material establishing the histologic type of tumor, histologic grade, tumor configuration, depth of invasion of the bladder wall, and depth of the bladder wall available for assessment. If possible, the size of the tumor and the presence of associated carcinoma in situ should also be reported. Imaging studies play a smaller role in the clinical staging of bladder cancer. However, when initial staging procedures point to invasion of the muscularis propria, chest X-ray, bone scan, and computed tomography scan of the abdomen and pelvis may provide valuable information about possible metastases. Whereas the clinical staging is essential to select and evaluate therapy, the pathologic stage (pTNM) provides the most precise data with which to estimate prognosis and calculate end results. The pathologic assessment entails resection of the primary tumor or a biopsy adequate to evaluate the highest pT category, removal of lymph nodes adequate to validate the absence of regional lymph node metastasis, as well as biopsy and microscopic examination for assessment of distant metastases. Although numerous factors have an impact on the behaviour of the malignancy, in bladder cancer the anatomic extent of disease reflected in the current staging classification remains the most powerful indicator of outcome.