MR staging of bladder carcinoma: correlation with pathologic findings

Advancements in optical techniques and imaging in the diagnosis and management of bladder cancer

Accurate detection and staging is critical to the appropriate management of urothelial cancer (UC). The use of advanced optical techniques during cystoscopy is becoming more widespread to prevent recurrent nonmuscle invasive bladder cancer. Standard of care for muscle-invasive UC includes the use of computed tomography and/or magnetic resonance imaging, but staging accuracy of these tests remains imperfect. Novel imaging modalities are being developed to improve current test performance. Positron emission tomography/computed tomography has a role in the initial evaluation of select patients with muscle-invasive bladder cancer and in disease recurrence in some cases. Several novel immuno-positron emission tomography tracers are currently in development to address the inadequacy of current imaging modalities for monitoring of tumor response to newer immune-based treatments. This review summaries the current standards and recent advances in optical techniques and imaging modalities in localized and metastatic UC.

MR Imaging with Stir Technique and Air Insufflation for Local Staging of Bladder Neoplasms

Fifty-six patients with bladder carcinoma were studied with MR imaging for the assessment of the local stage, using the inversion recovery pulse sequence with fat suppression (STIR) with air in the bladder. With this technique images of the inner and the outer parts of the bladder wall were obtained, showing high contrast between the latter and the tumor (tumor/muscle contrast 89.9%). Four tumor stages were recognized: superficial neoplasms (Tis, Ta, and T1), partial wall infiltrating neoplasms (T2); total wall infiltrating neoplasms (T3a, T3b), and neoplasms involving other pelvic organs (T4). MR imaging was compared with histopathologic diagnosis obtained at transurethral resection or cystectomy. True-positive diagnosis was obtained in 80.4%; false-positive in 14.3% of cases; false-negative in 5.3%. Despite the relatively high incidence of over-staged neoplasms, STIR technique combined with air in the bladder allowed a good accuracy in local staging.

Comparison of Early Submucosal Enhancement and Tumor Stalk in Staging Bladder Urothelial Carcinoma

OBJECTIVE

The purpose of this study was to compare the efficacy of submucosal enhancement on dynamic contrast-enhanced MRI (DCE-MRI) and detection of a stalk on DWI for differentiating stage T1 from stage T2 bladder urothelial carcinoma.

SUBJECTS AND METHODS

Our prospective study was approved by the institutional medical ethics committee and informed consent was obtained from all patients. Fifty-nine patients (92 tumors in total) with urothelial bladder cancer underwent MRI within 2 weeks before surgery. Two image sets of T2-weighted MRI with DWI and T2-weighted with DCE-MRI were interpreted independently at 2-week intervals by two uroradiologists without any knowledge of the surgical or histologic findings. The tumor was categorized as stage T1 or lower when a stalk was evident at the tumor base on DWI or when continuous linear submucosal enhancement was detected in the early phase of DCE-MRI. Tumors without stalks or with discontinuous linear submucosal enhancement were categorized as stage T2.

RESULTS

Of the 42 tumors with stalks on DWI, 41 showed continuous and one had discontinuous submucosal enhancement on DCE-MRI. In 50 carcinomas without stalks on DWI, submucosal enhancement was absent in 34, continuous in 12, and discontinuous in four. The staging accuracy of DWI (91.3%, 84/92) and DCE-MRI (91.3%, 84/92) was improved to 94.6% (87/92) by combining the interpretations of both DWI and DCE-MRI.

CONCLUSION

Submucosal linear enhancement under the tumor base on DCE-MRI complements tumor stalk detection on DWI for differentiating stage T1 from stage T2 bladder urothelial carcinoma.

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.

Nonmuscle-invasive and Muscle-invasive Urinary Bladder Cancer: Image Quality and Clinical Value of Reduced Field-of-view Versus Conventional Single-shot Echo-planar Imaging DWI

This study compared the imaging quality, diagnostic accuracy, and apparent diffusion coefficient (ADC) values of reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) and full field-of-view (fFOV) single-shot echo-planar imaging with regard to patients with nonmuscle-invasive or muscle-invasive bladder cancer.Thirty-nine patients with 60 bladder tumors underwent rFOV and fFOV DWI in this internal review board-approved study. Pathologic and histologic grades were determined for all tumors. Two observers rated DWI image quality using a 4-point scale. Two radiologists who were blinded to the pathology findings reviewed 3 image sets (T2-weighted alone, T2-weighted plus fFOV DWI, and T2-weighted plus rFOV DWI) and assigned T stages and confidence levels for tumors of stage T2 or higher. The image quality scores for the 2 DWI sequences were assessed using the Wilcoxon signed-rank test. Differences in the diagnostic accuracy, sensitivity, and specificity for each image set were evaluated using the McNemar test. Differences in performance were analyzed by comparing the areas under the receiver-operating characteristic curves (ie, the Az values). A Mann-Whitney U test was used to compare the mean ADCs and the relationship between tumor stage and histologic grade.Image quality scores were significantly higher for rFOV (mean = 3.62) than for fFOV DWI (2.98; P < 0.001). The pooled diagnostic accuracies were 57%, 70%, and 78% for the T2-weighted alone images, the T2-weighted plus fFOV DWI images, and the T2-weighted plus rFOV DWI images, respectively. The overall accuracy, specificity, and Az for diagnosing T2 or higher stages were significantly improved by adding rFOV DWI (P < 0.05). The mean ADC values of the muscle-invasive and G3 grade bladder cancers were significantly lower than those of the nonmuscle-invasive tumors and G1 grade cancers, regardless of DWI sequence (P < 0.01).rFOV DWI is superior to fFOV DWI with respect to image quality and diagnostic accuracy. ADC values might be useful for distinguishing nonmuscle-invasive from muscle-invasive cancers, and G1 from G3 grade lesions.

Role of consolidative surgical therapy in patients with locally advanced or regionally metastatic bladder cancer

The effect of radical cystectomy and extended pelvic lymph node dissection (RC/PLND) on the survival of patients with locally advanced and/or regionally metastatic bladder cancer is unknown. However, emerging evidence suggests that there may be survival benefit to a subset of select patients with this disease who demonstrate a response to chemotherapy. This article will review the current literature on the role of RC/PLND in the consolidative treatment of locally advanced and regionally metastatic bladder cancer.

Comparison of dynamic contrast-enhanced and diffusion weighted magnetic resonance image in staging and grading of carcinoma bladder with histopathological correlation

BACKGROUND

Bladder cancer is the second most common neoplasm of the urinary tract worldwide. Dynamic contrast-enhanced and diffusion-weighted MRI has been introduced in clinical MRI protocols of bladder cancer because of its accuracy in staging and grading.

AIM

To evaluate and compare accuracy of Dynamic contrast enhanced (DCE) and Diffusion weighted (DW) MRI for preoperative T staging of urinary bladder cancer and find correlation between apparent diffusion coefficient (ADC) and maximum enhancement with histological grade.

MATERIALS AND METHODS

Sixty patients with bladder cancer were included in study. All patients underwent Magnetic Resonance Imaging (MRI) on a 1.5-T scanner with a phased-array pelvic coil. MR images were evaluated and assigned a stage which was compared with the histolopathological staging. ADC value and maximum enhancement curve were used based on previous studies. Subsequently histological grade was compared with MR characteristics.

RESULTS

The extent of agreement between the radiologic staging and histopathological staging was relatively greater with the DW-MRI (κ=0.669) than DCE-MRI (κ=0.619). The sensitivity, specificity, and accuracy are maximum and similar for stage T4 tumors in both DCEMRI (100.0, 96.2 and 96.7) and DW-MRI (100.0, 96.2 and 96.7) while minimum for stage T2 tumors - DCEMRI (83.3, 72.2, and 76.7) and DWI-MRI (91.7, 72.2, and 80).

CONCLUSION

MRI is an effective tool for determining T stage and histological grade of urinary bladder cancers. Stage T2a and T2b can be differentiated only by DCE-MRI. Results were more accurate when both ADC and DCE-MRI were used together and hence a combined approach is suggested.

Neoadjuvant gemcitabine and carboplatin followed by immediate cystectomy may be associated with a survival benefit in patients with clinical T2 bladder cancer

Neoadjuvant cisplatin-based chemotherapy for muscle-invasive bladder cancer (MIBC) is more beneficial for clinical T3/4 than clinical T2 (cT2) disease. The aim of this study was to assess whether neoadjuvant GCarbo has a survival impact on cT2 bladder cancer. We retrospectively reviewed the medical records of 363 consecutive patients who underwent radical cystectomy (RC) between April 1997 and May 2012. We focused on 150 patients with cT2 MIBC. Seventy-nine patients received neoadjuvant GCarbo between March 2005 and April 2013. These patients received two courses of GCarbo and RC, and bilateral pelvic lymph node dissection (PLND) was performed at an interval of 1 month after chemotherapy. The control cohort included 71 patients with cT2 bladder cancer treated with RC and bilateral PLND alone between May 1994 and May 2007. Propensity score matching was used to adjust for potential selection biases associated with the treatment types. The endpoints were overall (OS), disease-specific (DSS), and disease-free survival (DFS). Propensity score-matched analysis resulted in 71 matched pairs from both groups. The 5-year OS rate was 98.6 % for the neoadjuvant GCarbo group and 66.6 % for the RC-alone group (p < 0.0001). The 5-year DSS rate was 100 % for the neoadjuvant GCarbo group and 69.7 % for the RC-alone group (p < 0.0001). The 5-year DFS rate was 94.2 % for the neoadjuvant GCarbo group and 72.7 % for the RC-alone group (p < 0.0001). In cT2 MIBC patients, neoadjuvant GCarbo chemotherapy followed by immediate cystectomy may improve OS and DFS compared to RC alone.

Clinical value of T2-weighted imaging combined with diffusion-weighted imaging in preoperative T staging of urinary bladder cancer: a large-scale, multiobserver prospective study on 3.0-T MRI

RATIONALE AND OBJECTIVES

To prospectively assess the incremental value of diffusion-weighted imaging (DWI) combined with T2-weighted images (T2WI) in determining the T stage of bladder cancer by using pathologic findings as the reference standard.

MATERIALS AND METHODS

This study is approved by the institutional review board; informed consent was waived. The study includes 362 patients (age range, 48-87 years; mean, 71 years) who underwent 3.0-T magnetic resonance imaging and histologic examination. Three observers with varying experience levels reviewed the T2WI data alone, DWI data alone, and combined T2WI and DWI data. Sensitivity, specificity, accuracy, and area under curve (AUC) were determined with the Z test after adjusting for data clustering.

RESULTS

For differentiating Tis to T1 tumors from T2 to T4 tumors, the AUCs for T2WI and DWI (0.97 for observer 1 and 0.96 for observer 2) were greater than those for the DWI alone (0.92 for observer 1 and 0.90 for observer 2) (P < .05). Observer 3 had similar AUCs for T2WI and DWI compared to DWI alone. The accuracy of T2WI and DWI (observer 1, 98%; observer 2, 96%; observer 3, 92%) was greater than that of DWI alone (observer 1, 92%; observer 2, 90%; observer 3, 87%) for all observers (P < .05). The specificity of T2WI and DWI (observer 1, 100%; observer 2, 98%; observer 3, 93%) was greater than that of DWI alone (observer 1, 92%; observer 2, 90%; observer 3, 87%) for all observers (P < .05). Sensitivity was not improved even when T2WI and DWI were used. For differentiating Tis to T2 Tumors from T3 to T4 Tumors, the overall accuracy, specificity, and AUC for diagnosing T2 or higher stages were not significantly improved by combiningT2WI and DWI.

CONCLUSIONS

T2WI combined with DWI can be a reliable sequence for preoperative evaluation of T stage urinary bladder cancer. It is particularly more useful in differentiating T1 or lower tumors from T2 or higher tumors compared to DWI alone.

Diagnostic performance of diffusion-weighted magnetic resonance imaging in bladder cancer: potential utility of apparent diffusion coefficient values as a biomarker to predict clinical aggressiveness

OBJECTIVES

The diagnostic performance of diffusion-weighted magnetic resonance imaging (DW-MRI) in bladder cancer and the potential role of apparent diffusion coefficient (ADC) values in predicting pathological bladder cancer phenotypes associated with clinical aggressiveness were investigated.

METHODS

One hundred and four bladder cancer patients underwent DW-MRI and T2-weighted magnetic resonance imaging (T2W-MRI) before transurethral resection. The image sets were reviewed by two independent radiologists. ADC values were measured in 121 eligible tumours.

RESULTS

In detecting patients with bladder cancer, DW-MRI exhibited high sensitivity equivalent to that of T2W-MRI (>90%). Interobserver agreement was excellent for DW-MRI (κ score, 0.88) though moderate for T2W-MRI (0.67). ADC values were significantly lower in high-grade (vs. low-grade, P < 0.0001) and high-stage (T2 vs. T1 vs. Ta, P < 0.0001) tumours. At a cut-off ADC value determined by partition analysis, clinically aggressive phenotypes including muscle-invasive bladder cancer (MIBC) and high-grade T1 disease were differentiated from less aggressive phenotypes with a sensitivity of 88%, a specificity of 85% and an accuracy of 87%.

CONCLUSION

DW-MRI exhibits high diagnostic performance in bladder cancer with excellent objectivity. The ADC value could potentially serve as a biomarker to predict clinical aggressiveness in bladder cancer.

Prognostic value of CA 125 in transitional cell carcinoma of the bladder

Recent studies have reported that serum cancer antigen (CA) 125 levels may be associated with pathological and survival outcomes in patients with bladder cancer to an extent that may support further investigation of clinical utility as a prognostic biomarker. The limitations of conventional bladder cancer staging prompted our institution to evaluate the association of CA 125 with pathological stage and tumor recurrence after radical cystectomy. Conventionally utilized for the management of ovarian cancer, the ability to detect CA 125 in transitional cell carcinoma tissue and urine of patients with transitional cell carcinoma raises the possibility that bladder cancer may be another indication for such testing. This article evaluates the current literature supporting the role of CA 125 as a biomarker with potential applications in patients with transitional cell carcinoma of the bladder undergoing radical cystectomy and urinary diversion. This article demonstrates that preoperative serum CA 125 levels may serve as a useful predictor of pathological outcomes above grade and stage in patients undergoing cystectomy for urothelial carcinoma of the bladder. The findings also show the potential use of preoperative CA 125 levels to predict unresectable tumors and clarify which candidates should receive neoadjuvant therapy.

Clinicopathological outcomes after radical cystectomy for clinical T2 urothelial carcinoma: further evidence to support the use of neoadjuvant chemotherapy

OBJECTIVE

To evaluate the clinicopathological outcomes for patients with clinical T2 (cT2) urothelial carcinoma treated with radical cystectomy (RC) without neoadjuvant chemotherapy (NC).

PATIENTS AND METHODS

We identified 212 patients with cT2 tumours who underwent RC at our institution without NC. Pathological assessment of RC specimens was correlated with clinical stage. The impact of various clinicopathological factors on the outcome of patients with cT2 disease was analysed.

RESULTS

In total, 153/212 (73.2%) patients with cT2 bladder cancer had either pT3/T4 or pN+ tumours at RC. Moreover, only 58/153 (37.9%) of these patients received adjuvant chemotherapy. The median follow-up was 28 (months 0.6-107.5) (range). The 5-year recurrence-free survival and cancer-specific survival (CSS) was 56.5% and 59.5%, respectively. On multivariate analysis, increasing age (hazard ratio [HR] 1.04; P= 0.04), advanced pathological stage (HR 1.83; P= 0.02), and positive lymph nodes (HR 3.72; P= 0.001) were adversely associated with CSS, while receipt of adjuvant chemotherapy was protective of disease-specific mortality (HR 0.45; P= 0.04).

CONCLUSIONS

Pathological upstaging is prevalent and survival remains modest in patients with cT2 tumours treated with RC without NC. Unfortunately, only 40% of patients that had locally advanced and/or regionally metastatic disease received adjuvant treatment. These data further support the value of NC for patients with muscle-invasive bladder cancer, even in those with apparent clinically organ-confined tumours.

Clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in bladder cancer

PURPOSE

Fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) has been approved for imaging in many malignancies but not for bladder cancer. This study investigated the value of FDG-PET/CT imaging in the management of patients with advanced bladder cancer.

PATIENTS AND METHODS

Between May 2006 and February 2008, 57 patients with bladder cancer at our center underwent FDG-PET/CT after CT (n = 52) or magnetic resonance imaging (MRI; n = 5). The accuracy of FDG-PET/CT was assessed using both organ-based and patient-based analyses. FDG-PET/CT findings were validated by either biopsy or serial CT/MRI. Clinician questionnaires performed before and after FDG-PET/CT assessed whether those scan results affected management.

RESULTS

One hundred thirty-five individual lesions were evaluable in 47 patients for the organ-based analysis. Overall sensitivity and specificity were 87% (95% CI, 76% to 94%) and 88% (95% CI, 78% to 95%), respectively. In the patient-based analysis, malignant disease was correctly diagnosed in 25 of 31 patients, resulting in a sensitivity of 81% (95% CI, 63% to 93%). FDG-PET/CT was negative in 15 of 16 patients without malignant lesions for a specificity of 94% (95% CI, 71% to 100%). Pre- and post-PET surveys revealed that FDG-PET/CT detected more malignant disease than conventional CT/MRI in 40% of patients. Post-PET surveys showed that clinicians changed their planned management in 68% of patients based on the FDG-PET/CT results.

CONCLUSION

FDG-PET/CT has excellent sensitivity and specificity in the detection of metastatic bladder cancer and provides additional diagnostic information that enhances clinical management more than CT/MRI alone. FDG-PET/CT scans may provide better accuracy in clinical information for directing therapy.

Prospective study of [18F]fluorodeoxyglucose positron emission tomography/computed tomography for staging of muscle-invasive bladder carcinoma

PURPOSE

Novel imaging modalities are needed to detect occult metastatic disease in bladder carcinoma. Patients with regional lymphatic spread could be targeted for neoadjuvant chemotherapy, and patients with distant metastatic disease could be spared the unnecessary morbidity of radical cystectomy. Herein, we report a prospective study of positron emission tomography/computed tomography (PET/CT) with [(18)F]fluorodeoxyglucose (FDG) in patients undergoing radical cystectomy for cT2-3N0M0 urothelial carcinoma of the bladder.

METHODS

Forty-three chemotherapy-naïve patients underwent FDG-PET/CT before planned cystectomy. All had negative conventional CT and bone scintigraphy before enrollment. Positive FDG-PET/CT was confirmed by percutaneous biopsy or open surgical exploration, whereas negative FDG-PET/CT was confirmed by complete lymphadenectomy. Recurrence-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) were described using the Kaplan-Meier method and compared using log-rank test.

RESULTS

Median follow-up was 14.9 months (range, 0.4 to 46.1 months). One patient who did not undergo lymphadenectomy was excluded from the pathology data analysis (n = 42), whereas another patient who failed to return for follow-up was excluded from survival analysis (n = 42). FDG-PET/CT demonstrated a positive predictive value of 78% (seven of nine), a negative predictive value of 91% (30 of 33), sensitivity of 70% (seven of 10), and specificity of 94% (30 of 32). RFS, DSS, and OS were all significantly poorer in the patients with positive FDG-PET/CT than in those with negative FDG-PET/CT.

CONCLUSION

FDG-PET/CT detected occult metastatic disease in seven of 42 patients with negative conventional preoperative evaluations. PET findings were strongly correlated with survival. As such, FDG-PET/CT may help in making treatment decisions before radical cystectomy.

Urinary bladder cancer: diffusion-weighted MR imaging--accuracy for diagnosing T stage and estimating histologic grade

PURPOSE

To prospectively evaluate the ability of diffusion-weighted (DW) magnetic resonance (MR) imaging to be used to determine the T stage of bladder cancer and to measure the correlation between the apparent diffusion coefficient (ADC) and histologic grade.

MATERIALS AND METHODS

This study was approved by the local institutional review board. All patients gave written informed consent. Forty patients with a total of 52 bladder tumors underwent MR imaging that included DW imaging. Histologic grade was determined for all tumors. Two radiologists interpreted four image sets (ie, T2-weighted images alone, T2-weighted plus DW images, T2-weighted plus dynamic contrast agent-enhanced images, all three image types together). Conventional criteria were used for interpreting T2-weighted and contrast-enhanced images. For DW images, new staging criterion developed on the basis of the hypothesis that tumors, submucosal tissue, and muscles show high, low, and intermediate signal intensity, respectively, was used. The McNemar test was used to examine differences in accuracy, sensitivity, and specificity. Differences in the performance were analyzed by comparing the areas under the receiver operating characteristic curves (A(z) values). To compare ADCs between three histologic grades, analysis of variance was used.

RESULTS

The overall accuracy of T stage diagnosis was 67% for T2-weighted images alone, 88% for T2-weighted plus DW images, 79% for T2-weighted plus contrast-enhanced images, and 92% for all three image types together. The overall accuracy, specificity, and A(z) for diagnosing T2 or higher stages were significantly improved by adding DW images (P < .01). The mean ADC of G3 tumors was significantly lower than that of G1 and G2 tumors (P < .01).

CONCLUSION

DW images provided useful information for evaluating the T stage of bladder cancer, particularly in differentiating T1 or lower tumors from T2 or higher tumors. The ADC may in part predict the histologic grade of bladder cancer.

Clinical use of serum CA-125 levels in patients undergoing radical cystectomy for transitional cell carcinoma of the bladder

PURPOSE

It has recently been reported that serum CA-125 levels may serve as a prognostic indicator of extravesical disease in patients with bladder cancer. This study evaluated the role of CA-125 as a prognostic marker in patients with transitional cell carcinoma of the bladder undergoing radical cystectomy and urinary diversion.

METHODS

Ninety-two consecutive patients underwent planned radical cystectomy and urinary diversion with curative intent (2005-2006). Serum CA-125 levels were obtained in all patients and correlations were made to clinical and operative findings and pathological outcomes. Outcomes were evaluated with regard to normal vs. abnormal CA-125 values and with regard to absolute values of CA-125 levels. Results were also stratified by short-term recurrence rates.

RESULTS

Mean CA-125 values varied significantly by pathological stage and by resectability. No patient (0/56) with organ-confined disease (<or= pT2N0) had an abnormal CA-125, and only 1 patient (1/75 = 1.3%) with <or= pT3N0 disease had an abnormal value. Conversely, 35% of patients with regionally-advanced disease (pT4 or N+) had an elevated CA-125, and all patients with unresectable disease (5/5) had an elevated value. In addition, patients with abnormal values of CA-125 (i.e., <35 U/ml) had a significantly higher upstaging rate compared to non-upstaged patients (18.8% vs. 3.5%, respectively; P = 0.0233). As well, patients with CA-125 levels <15 U/ml had a significantly higher upstaging rate compared with non-upstaged patients (53.1% vs. 15.8%, respectively; P = 0.0005). At a mean follow-up of 15 months (median = 14 months), patients with T2/T3N0 disease who recurred had a higher mean value than patients with pT2/T3 disease who did not recur (20.1 vs. 10.8 U/ml).

CONCLUSIONS

Serum CA-125 levels may serve as a useful predictor of pathological outcomes in patients undergoing cystectomy for urothelial carcinoma of the bladder. Further studies will be carried out to determine the predictability of CA-125 on long-term recurrence and survival rates, and to evaluate the utility of CA-125 as a marker for disease response in patients with recurrent or advanced disease undergoing systemic therapy.

Imaging of Bladder Cancer

Bladder cancer is a heterogeneous and frequently multifocal disease with a variable clinical course. The management of bladder cancer is therefore challenging and complicated. CT and MR imaging have replaced the traditional excretory urography and are emerging as the imaging modalities of choice for work-up of patients who have bladder cancer. Imaging provides essential diagnostic information for detection, staging, and post-treatment follow-up of bladder cancer.

Nuclear Medicine Studies of the Prostate, Testes, and Bladder

During the last decade, there has been a significant advancement in imaging of urologic diseases. Transrectal ultrasound (TRUS), computerized tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and positron emission tomography (PET) are still experiencing new developments in urology. Despite these many technological advances, the initial diagnostic procedure for a patient with suspected prostate cancer (PC) is multiple site blind prostate biopsies. There is a need for a noninvasive metabolic imaging modality to direct the site of biopsy to decrease the sampling error. MRS seems promising but as it is a costly and more time-consuming test, further studies are needed to evaluate its clinical utility. Currently, PET does not play any role to direct biopsy. Acetate and choline appear to be better tracers than FDG for the detection of a prostate lesion, however, further well-organized studies are needed before any of these agents can be used clinically. Incidental detection of intense focal uptake in the prostate during whole body PET scanning should be evaluated with prostate-specific antigen (PSA) and TRUS-guided biopsy. Although FDG is inferior to other tracers for primary staging, it may be useful in selected patients with suspected high-grade cancer. The role of ProstaScint scan is still controversial for detection of recurrent PC. This study may be helpful for evaluating nodal metastases when PSA is elevated and bone scan is negative. Bone scan remains the study of choice when bone metastases are suspected (PSA>15-20 ng/mL+/-bone pain). Acetate and choline provide better accuracy than FDG in the detection of local soft tissue disease, nodal involvement, and distant metastases. High FDG uptake may be indicative of more aggressive and possibly androgen-independent disease. PET/CT with any of the above PET tracers will most likely be preferred to the PET scan alone due to better localization of a hot lesion in PET/CT. Nuclear medicine studies also have been used to evaluate acute scrotum and testicular neoplasms. Scrotal scintigraphy has lost its popularity to Doppler ultrasound in the evaluation of the acute scrotum. In testicular tumors, FDG-PET appears to be superior to conventional imaging modalities in initial staging, detection of residual/recurrence, and monitoring treatment response. Tumor markers after treatment occasionally are elevated and cannot locate the site of recurrence, FDG-PET can play a very important role in this regard. Nuclear medicine studies also have been used to evaluate diseases of the urinary bladder. Radionuclide cystography is more sensitive and has less than 1/20 the radiation exposure of the conventional contrast enhanced micturating cystourethrogram (MCU). However, the utility of FDG-PET in the evaluation of bladder cancer seems to be limited to the evaluation of distant metastases. 11C-Methionine and choline may be a better option for local and nodal disease due to their negligible excretion in the urine.

Dynamic MRI of bladder cancer: evaluation of staging accuracy

OBJECTIVE

The purpose of this study was to evaluate the accuracy of gadoliniumenhanced MRI in staging bladder cancer in a series of patients with surgically proven bladder cancer.

MATERIALS AND METHODS

Seventy-one patients with biopsy-proven bladder cancer underwent MRI on a 1.5-T scanner with a phased-array pelvic coil. Conventional T1-weighted spin-echo, T2-weighted spin-echo, and unenhanced and enhanced (0.1 mmol/kg gadolinium) fast spoiled gradient-echo images with fat suppression were obtained. Two blinded reviewers evaluated the MR images and assigned a stage that was compared with the pathologic stage (n = 67) or with clinical follow-up for at least 2 years after MRI (n = 4).

RESULTS

Agreement among the reviewers was good in assigning a radiologic stage for bladder cancer (kappa = 0.80). On a stage-by-stage basis, MRI accuracy was 62%, and overstaging was the most common error (32%). Staging accuracy improved to 85% and 82% in differentiating superficial from invasive tumors and organ-confined from non-organ-confined tumors, respectively. The time interval between MRI and transurethral resection (</= 60 days and >/=61 days) was not a statistically significant factor in differentiating superficial from invasive and organ-confined from non-organ-confined tumors (p > 0.05). MRI accuracy in staging transitional cell carcinoma was not significantly different from that obtained in staging non-transitional cell carcinoma (p > 0.05).

CONCLUSION

MRI shows good reproducibility between reviewers for staging bladder cancer. Although overall staging accuracy was only moderate, the accuracy for differentiating superficial versus invasive disease and organ-confined versus non-organ-confined disease was high.

MR imaging of the bladder

MR imaging is a useful modality for evaluating diseases of the bladder. MR imaging can detect and stage bladder cancer by determining the presence and depth of muscle invasion. Direct multiplanar imaging and superb soft-tissue contrast make MR imaging an ideal modality for evaluating less common neoplastic diseases of the bladder, such as urachal carcinoma, and tumors that develop within bladder diverticula. Dynamic breath-held fast T2-weighted imaging can evaluate for cystocele and other components of pelvic floor relaxation.

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.

Positron emission tomography in urologic oncology

BACKGROUND

Positron emission tomography (PET) is an emerging imaging modality that is being investigated for use in urologic oncology. PET scanning using the radioactive glucose analog FDG has proven to be a highly accurate imaging test for diagnosing and staging a variety of non-urologic cancer types. This review was performed to determine the role of PET imaging in genitourinary malignancies.

METHODS

A review of the literature focusing on PET and urologic oncology was performed. The role of PET imaging was reviewed in prostate, bladder, renal, and testicular cancer.

RESULTS

In testicular cancer, PET has a higher diagnostic accuracy than computed tomography (CT) for both staging and re-staging and should be the test of choice for the assessment of a CT-visualized residual mass following chemotherapy. In prostate, renal, and bladder cancer, the current role of PET is still being defined, but it has a high positive predictive value and can be used for problem solving in patients with indeterminate findings on conventional imaging. Its role in the diagnosis and staging of prostate cancer is hampered by the generally low glycolytic rate of most prostate tumors and their metastases. It has shown promise for staging and re-staging patients with advanced-stage disease and aggressive tumors suspected by a high tumor grade and high prostate-specific antigen velocity. PET has also demonstrated success when applied to renal cell carcinoma in classifying indeterminate renal masses as well as residual renal fossa masses following nephrectomy, gauging response to therapy, and staging and re-staging patients with a known diagnosis of renal cell carcinoma.

CONCLUSIONS

PET imaging has demonstrated great potential in certain applications, but further investigations are necessary to determine its eventual place as an imaging modality in genitourinary malignancies.

Positron emission tomography in urological malignancy

Positron emission tomography is a unique imaging modality with the capability of studying regional metabolism. The major clinical applications of positron emission tomography have been in the detection of brain, breast, cardiac, lung and colorectal tumours, as well as the evaluation of coronary artery disease by imaging the metabolism of heart muscle. In the field of urology, positron emission tomography has been evaluated in the relevant malignancies with promising results in certain areas and disappointing results in others. This article attempts to summarize recent advances in positron emission tomography scanning with regards to urological malignancy. At this stage positron emission tomography scanning is capable of visualizing urological tumours and associated lymph nodes and distal metastatic sites. However, its use is severely limited by the excretion of the most commonly used radioisotope via the urinary tract, making pelvic imaging particularly unrewarding. It is, however, undoubtedly capable of diagnosing malignancy in soft tissue masses or lymph nodes before these changes become apparent on conventional cross-sectional imaging modalities (computerized tomography or magnetic resonance imaging). Larger studies are required before it can be advocated for clinical use in the field of urology.

Current concepts in assessment and treatment of bladder cancer

Transitional cell carcinoma of the bladder is comprised of a variety of cancer diatheses that manifest a spectrum of distinct biologic potentials. The challenge is to control superficial disease recurrence and progression and to identify invasive carcinoma at an earlier stage, when it may be more amenable to cure.

Histopathological analysis of a bladder cancer stalk observed on MRI

Papillary transitional cell carcinoma of the bladder has a loose connective tissue stalk. For staging of bladder cancer on magnetic resonance imaging (MRI), it is important to clearly separate the cancer from the bladder wall. It is possible to distinguish a stalk from the cancer by the difference of intensity on the using MRI. Sixteen stalks of 20 polypoid bladder tumors on any of the T(2)W(I), dynamic images and delayed enhanced images were demonstrated. Most of the stalks show lower signal intensity than the tumors on T(2)W(I), less enhancement on dynamic images and stronger enhancement on delayed enhanced images. The stalk consisted of fibrous connective tissue, capillary blood vessels, inflammatory cell infiltration and edema. This stalk extended from the bladder wall to the center of the tumor. Some of the superficial muscular bundles were pulled into the stalk. These histopathological findings were compatible with the patterns of signal intensities on MRI. The identification of the stalk of a polypoid tumor may be an important observation to exclude bladder wall invasion by tumor.

Magnetic resonance imaging of urinary bladder cancer

The treatment and prognosis of urinary bladder cancer are largely determined by the tumour stage and the presence or not of metastases. Magnetic resonance imaging and clinical staging complement each other. Magnetic resonance imaging is the most accurate technique for differentiating the various stages of deep tumour infiltration and for detecting metastases, whereas clinical staging is the best technique for differentiating between post-biopsy effects and the various stages of superficial tumours. The role played by magnetic resonance imaging in the staging of this disease and the monitoring of therapy is reviewed and illustrated. Finally, the authors present an overview of the current and future applications of this technique.

MR imaging of the prostate and bladder

Magnetic resonance imaging has become an important imaging modality for the male pelvis. Its unparalleled ability to depict soft tissue structures and highlight pathology have made it the best method for determining the extent of many disease processes. This article reviews the use of MR to evaluate diseases of the prostate gland and bladder. In both, the major indication for imaging is the local staging of cancer, and MR is currently the best imaging modality. This article will discuss the critical clinical issues concerning prostate cancer and neoplasms of the bladder, and the contribution of MR imaging.

Normal bladder wall morphology in Gd-DTPA-enhanced clinical MR imaging using an endorectal surface coil and histological assessment of submucosal linear enhancement using [14C]Gd-DOTA autoradiography in an animal model

OBJECTIVE

The purpose of this study was to investigate normal bladder wall morphology in gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance (MR) imaging using an endorectal surface coil and to perform histological assessment of submucosal linear enhancement with experimental [14C]-gadolinium-tetraazacyclododecane-tetraacetic acid (Gd-DOTA) autoradiography.

METHODS AND MATERIAL

MR imaging of the bladder was performed using an endorectal coil in 13 consecutive patients with bladder carcinoma and T1-, T2-, and Gd-DTPA-enhanced spin-echo images of the bladder wall were compared. After injection of [14C]Gd-DOTA into a hamster, autoradiograms of the bladder wall were obtained and compared with serial histological sections.

RESULTS

The normal bladder wall appeared as a homogeneous layer of intermediate intensity on T1-weighted images. After administration of Gd-DTPA, the bladder wall was visualized as three layers: an inner thin layer of low intensity, a middle layer of marked enhancement, and a thick outer layer of intermediate intensity. The autoradiograms demonstrated dense accumulation of [14C]Gd-DOTA in the submucosal layer. Thus, the inner, middle, and outer layers corresponded to the mucosa, submucosa, and muscularis propria, respectively. The thickness of the bladder wall demonstrated on T2-weighted images was almost equal to that of the outer layer on enhanced T1-weighted images. Thus, T2-weighted images revealed only the muscle layer as an intermediate-intensity band. In the preliminary clinical study, MR imaging invariably showed accurate stages of the bladder carcinoma in 13 patients.

CONCLUSION

In MR imaging of the normal bladder wall, the submucosa was strikingly enhanced after Gd-DTPA administration, separating the bladder wall into three layers. This may have a potential role in the staging of bladder tumors.

What is new in bladder cancer imaging

Treatment and prognosis of urinary bladder cancer largely are determined by the tumor stage and presence of metastases. MR imaging and clinical staging complement each other. MR imaging is the most accurate technique for differentiating the various stages of deep tumor infiltration and detection of metastases, whereas clinical staging is the best technique for differentiating between postbiopsy effects and the various stages of superficial tumors. The role of MR imaging in staging of this disease and monitoring of therapy is reviewed and illustrated. Finally, the authors present an overview of current and future applications of this technique.

Preliminary assessment of fluorine-18 fluorodeoxyglucose positron emission tomography in patients with bladder cancer

The purpose of this study was to assess the feasibility of imaging of bladder cancer with fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scanning. We studied 12 patients with histologically proven bladder cancer who had undergone surgical procedures and/or radiotherapy. Retrograde irrigation of the urinary bladder with 1000-3710 ml saline was performed during nine of the studies. Dynamic and static PET images were obtained, and standardized uptake value images were reconstructed. FDG-PET scanning was true-positive in eight patients (66.7%), but false-negative in four (33.3%). Of 20 organs with tumor mass lesions confirmed pathologically or clinically, 16 (80%) were detected by FDG-PET scanning. FDG-PET scanning detected all of 17 distant metastatic lesions and two of three proven regional lymph node metastases. FDG-PET was also capable of differentiating viable recurrent bladder cancer from radiation-induced alterations in two patients. In conclusion, these preliminary data indicate the feasibility of FDG-PET imaging in patients with bladder cancer, although a major remaining pitfall is intense FDG accumulation in the urine.

The use of dynamic magnetic resonance imaging to evaluate orthotopic continent urinary diversion

OBJECTIVES

The purpose of this study was to evaluate a dynamic magnetic resonance (MR) examination in patients after radical cystoprostatectomy with a neobladder.

METHODS

All 12 subjects were studied with the injection of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) and showed normal renal enhancement patterns and upper urinary tracts, except 1 patient who had mild right hydronephrosis. All neobladders were also visualized with gadolinium and 9 of 11 patients were able to void on command. There was close agreement in all cases with the MR findings and other imaging studies.

RESULTS

A static and dynamic Gd-DTPA contrast medium MR did image the entire urinary system, similar to a computed tomographic scan or intravenous urogram. Renal function data, similar to a renal radioisotope scan, was obtained from the Gd-DTPA scans. A dynamic voiding study provided visualization of the lower genitourinary tract similar to a conventional voiding cystourethrogram.

CONCLUSIONS

We conclude that this single MR technique may provide information similar to that obtained from multiple standard imaging studies in the postoperative assessment of the radical cystectomy patient with a neobladder. It may be especially helpful in the presence of azotemia or contrast allergy.