BACKGROUND: Current imaging techniques are of limited value for lymph node (LN) staging in bladder cancer (BCa) patients scheduled for radical cystectomy (RC).
OBJECTIVE: Evaluate the diagnostic efficacy of [11C]choline positron emission tomography in combination with computed tomography (PET/CT) for LN staging of patients with BCa scheduled for RC and compare that efficacy with the diagnostic efficacy of CT and the gold standard of histopathologic evaluation.
DESIGN, SETTING, AND PARTICIPANTS: From June 2004 to May 2007, 44 patients with localized BCa were staged with [11C]choline PET with low-dose CT for attenuation correction and simultaneous intravenous and rectal contrast-enhanced diagnostic CT before RC and pelvic lymph node dissection (PLND). LNs were dissected from the internal and external iliac arteries up to the origin of the inferior mesentery artery according to a template with 14 predefined anatomic fields.
INTERVENTION: Diagnostic [11C]choline PET/CT before RC and regional LN dissection.
MEASUREMENTS: Histopathologic findings of resected LN were correlated with the results of [11C]choline PET/CT and CT alone in a patient- and field-based manner. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of [11C]choline PET/CT and CT were assessed.
RESULTS AND LIMITATIONS: LN metastases were found in 12 of 44 patients (27%). On patient-based analysis, sensitivity, specificity, PPV, NPV, and accuracy for [11C]choline PET/CT were calculated as 58%, 66%, 39%, 81%, and 64%, respectively; and for CT the calculated percentages were 75%, 56%, 39%, 86%, and 61%, respectively. Twenty-five of 471 dissected LN fields (5%) showed metastases. On field-based analysis, sensitivity, specificity, PPV, NPV, and accuracy for [11C]choline PET/CT were 28%, 95%, 21%, 96%, and 91%, respectively; for CT, the calculated percentages were 39%, 92%, 20%, 96%, and 90%, respectively. Limitations of this study are small patient number and the fact that not all patients underwent extensive PLND.
CONCLUSIONS: In patients with BCa who were scheduled for RC, preoperative LN staging with [11C]choline PET/CT was not able to improve diagnostic efficacy compared with conventional CT alone.
PURPOSE: 11C-choline was postulated to provide better diagnostic capabilities than other tracers used in positron emission tomography/computerized tomography for staging urothelial carcinoma. We compared the value of using 11C-choline with the well investigated 18F-FDG tracer in this setting.
MATERIALS AND METHODS: The study group included 20 consecutive patients with bladder cancer who underwent evaluation for local and metastatic disease using 11C-choline and 18F-FDG positron emission tomography/computerized tomography. Patients were treated with radical cystectomy with lymph node dissection, radiation therapy or chemotherapy independent of positron emission tomography/computerized tomography results. The histopathological findings (when available), followup positron emission tomography and radiological imaging served as the reference standard. Using the paired t test we compared the maximum standardized uptake and lesion-to-background ratio of the tracers. The positive predictive values were determined.
RESULTS: A total of 51 lesions showed abnormal tracer activity. The positive predictive value for all detected lesions was 84.7% for 11C-choline positron emission tomography/computerized tomography and 90.7% for 18F-FDG positron emission tomography/computerized tomography. The corresponding positive predictive values for extravesical lesions were 79.4% and 88.2%, respectively. Discrepant findings between the tracers were noted at 11 sites. 18F-FDG positron emission tomography/computerized tomography correctly identified 4 extravesical metastases missed by choline positron emission tomography/computerized tomography in the absence of a contrary observation. Mean maximum standardized uptake and lesion-to-background ratio at extravesical sites were significantly higher for FDG.
CONCLUSIONS: Within the limitations of a relatively small number of patients and partial histopathological analysis, 11C-choline positron emission tomography/computerized tomography appears to have no advantage compared to 18F-FDG positron emission tomography/computerized tomography in the detection of metastatic bladder cancer. 18F-FDG positron emission tomography/computerized tomography has a tendency toward greater accuracy.
PURPOSE: Current imaging modalities for preoperative staging of advanced transitional cell carcinoma of the bladder or upper urinary tract are not sensitive for detection of metastases. This study examines the contribution of 11C-choline positron emission tomography/computerized tomography to preoperative staging of transitional cell carcinoma.
MATERIALS AND METHODS: We prospectively evaluated 18 patients with 19 advanced transitional cell carcinomas (17 bladder tumors and 2 upper tract transitional cell carcinomas). All patients had computerized tomography of the chest, abdomen and pelvis negative for metastases. 11C-choline positron emission tomography/computerized tomography was performed on a Discovery ST(R) positron emission tomography/computerized tomography system. Finally 16 patients underwent radical surgery and positron emission tomography/computerized tomography images were compared to histopathological findings. Two patients were not operated on due to the findings on 11C-choline positron emission tomography/computerized tomography.
RESULTS: 11C-choline uptake was found in all primary transitional cell carcinomas, with a maximum standardized uptake value of 7.3 +/- 3.2 (mean +/- SD). The series included 3 patients with refractory bladder carcinoma in situ, which was visualized in all 3, with a standardized uptake value of 6.9 +/- 5.6. In 6 patients uptake of 11C-choline in lymph nodes as small as 5 mm was visualized (standardized uptake value 3.8 +/- 1.4). Of these patients 4 underwent surgery and histopathology confirmed malignancy in 3 of 4. No additional patients with positive lymph nodes were found on histopathology. Metastases were visualized in bones with normal architecture on computerized tomography in 4 patients (standardized uptake value 5.2 +/- 1.1) and were confirmed by followup computerized tomography.
CONCLUSIONS: In this small series 11C-choline positron emission tomography/computerized tomography was highly sensitive for primary and metastatic transitional cell carcinoma. Carcinoma in situ, lymph node metastases and early bony metastases were visualized. 11C-choline positron emission tomography/computerized tomography is a promising tool for preoperative staging of advanced transitional cell carcinoma.
UNLABELLED: Lymph node involvement is a major prognostic factor in bladder cancer, but the accuracy of conventional imaging modalities for the prediction of regional and distant metastatic diseases is limited. This study was performed to compare the diagnostic accuracies of contrast-enhanced CT and PET with (11)C-choline for the staging of urothelial bladder cancer.
METHODS: Twenty-seven patients (median age, 69.1 y) who had urothelial bladder cancer and who were referred for radical cystectomy and pelvic lymph node dissection (PLND) on the basis of a histologic evaluation after transurethral resection of bladder cancer (TURB) were studied. PET scanning, using 2 multiring whole-body tomographs, was performed 5 min after intravenous injection of approximately 370-500 MBq of (11)C-choline. In addition, conventional bone scintigraphy and contrast-enhanced CT were performed. After imaging, cystectomy and PLND were performed in all patients. Pathologic (11)C-choline uptake that could not be explained by intestinal activity was noted as a positive result. Node positivity was determined by size on CT: nodes measuring more than 1 cm in the long axis were described as being positive for tumor. Histopathologic findings were used as a reference.
RESULTS: The presence of residual bladder cancer (pTa-pT4) was correctly detected in 21 of 25 histologically tumor-positive patients (84%) by CT and in 24 of 25 patients (96%) by (11)C-choline PET. Lymph node involvement was correctly detected in 4 of 8 patients (50%) by CT and in 5 of 8 patients (62%) by (11)C-choline PET. The median size of the 3 nodes with false-negative PET results was 9 mm (range, 6-21 mm), and the median size of the metastatic lesions within the lymph nodes was 3 mm (range, 1-15 mm). CT resulted in 6 (22%) false-positive lymph nodes, whereas none was demonstrated by (11)C-choline PET; these data indicated a significantly higher accuracy of PET than of CT (P < 0.01). Both modalities missed a small peritoneal metastasis verified by histologic evaluation. No positive results were obtained from bone scintigraphy.
CONCLUSION: These preliminary data suggest that (11)C-choline PET is comparable to CT for detecting residual bladder cancer after TURB but appears to be superior to CT for the evaluation of potential additional lymph node metastases. (11)C-choline PET should be further evaluated for staging in patients who have bladder cancer and who are scheduled for radical cystectomy.
Current imaging techniques are of limited value for lymph node (LN) staging in bladder cancer (BCa) patients scheduled for radical cystectomy (RC).
OBJECTIVE:
Evaluate the diagnostic efficacy of [11C]choline positron emission tomography in combination with computed tomography (PET/CT) for LN staging of patients with BCa scheduled for RC and compare that efficacy with the diagnostic efficacy of CT and the gold standard of histopathologic evaluation.
DESIGN, SETTING, AND PARTICIPANTS:
From June 2004 to May 2007, 44 patients with localized BCa were staged with [11C]choline PET with low-dose CT for attenuation correction and simultaneous intravenous and rectal contrast-enhanced diagnostic CT before RC and pelvic lymph node dissection (PLND). LNs were dissected from the internal and external iliac arteries up to the origin of the inferior mesentery artery according to a template with 14 predefined anatomic fields.
INTERVENTION:
Diagnostic [11C]choline PET/CT before RC and regional LN dissection.
MEASUREMENTS:
Histopathologic findings of resected LN were correlated with the results of [11C]choline PET/CT and CT alone in a patient- and field-based manner. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of [11C]choline PET/CT and CT were assessed.
RESULTS AND LIMITATIONS:
LN metastases were found in 12 of 44 patients (27%). On patient-based analysis, sensitivity, specificity, PPV, NPV, and accuracy for [11C]choline PET/CT were calculated as 58%, 66%, 39%, 81%, and 64%, respectively; and for CT the calculated percentages were 75%, 56%, 39%, 86%, and 61%, respectively. Twenty-five of 471 dissected LN fields (5%) showed metastases. On field-based analysis, sensitivity, specificity, PPV, NPV, and accuracy for [11C]choline PET/CT were 28%, 95%, 21%, 96%, and 91%, respectively; for CT, the calculated percentages were 39%, 92%, 20%, 96%, and 90%, respectively. Limitations of this study are small patient number and the fact that not all patients underwent extensive PLND.
CONCLUSIONS:
In patients with BCa who were scheduled for RC, preoperative LN staging with [11C]choline PET/CT was not able to improve diagnostic efficacy compared with conventional CT alone.
