OBJECTIVE: To determine whether to use 18F FDG PET scans in the preoperative staging of bladder cancer.
PATIENTS AND METHODS: All patients (N=233) with muscle invasive (MIBC) or high risk non-muscle invasive (NMIBC) bladder cancer being considered for radical surgery between 2005 and 2011 had FDG-PET and CT scan chest, abdomen and pelvis to assess for pelvic nodal involvement or distant metastases. Sensitivity and specificity for detecting pelvic lymph nodal involvement was determined by comparing the results of the scans to the histopathology reports in patients undergoing radical cystectomy. These parameters for distant metastases were determined from biopsy results or follow up imaging. In patients who did not undergo surgery, follow up imaging was used to evaluate the sensitivity and specificity. Patients were excluded from analysis if they either had neo-adjuvant chemotherapy or had less than 10 nodes removed at lymphadenectomy.
RESULTS: The PET scan was able to detect metastatic disease outside of the pelvis with a sensitivity of 54% compared to 41% for the staging CT (N=207). Both scans had similar specificities of 97% and 98%. There were 13 PET avid lesions not visualised on the corresponding staging CT scans. These proved to be metastatic bladder cancer (n=6), a synchronous primary colonic cancer (n=1), colonic adenomas (n=1), basal cell tumour of the parotid gland (n=1) and inflammatory lesions (n=4). The sensitivity and specificity of the CT scans for pelvic lymph nodal involvement was 45% and 98% respectively (N=93). Using combination of the PET and CT scan, the sensitivity for detecting metastatic disease in nodes increased to 69% with a 3% reduction in specificity to 95%.
CONCLUSIONS: PET scan when used in conjunction with a standard CT scan provides a small improvement in preoperative staging of bladder cancer. However, this advantage is not significant enough to justify the additional cost. Hence we recommend use of dual imaging only in highly selected patients.
Written by:
Goodfellow H, Viney Z, Hughes P, Rankin S, Rottenberg G, Hughes S, Dasgupta P, O'Brien T, Khan MS. Are you the author?
Guy's, King's and St Thomas' Medical school, Kings College London, London, SE1 1UL.
Reference: BJU Int. 2013 Dec 16. Epub ahead of print.
doi: 10.1111/bju.12608
PubMed Abstract
PMID: 24341486
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