Intraindividual comparison of 11C-choline and 11C-acetate PET/CT in bladder TCC

Objectives ¹¹C-choline (Chol) and ¹¹C-acetate (Acet) PET/CT have been shown to contribute to pre-operative staging of bladder TCC (BTCC). We compared the performance of both tracers in the same patients (pts).

Methods Eight male patients (age: 52-91) with biopsy proven BTCC were prospectively evaluated with Chol and Acet PET/CT scans before radical cystectomy. ROI's were defined around the vesical tumor (8 pts), foci in the prostate (4) and 10 lymph nodes (LNs). Background ROIs for the BTCC and prostate were drawn in the bladder and for the LNs in the sub-cutaneous fat . Range and mean of maximum SUVs and target-to-background ratios (T/Bkg) were calculated for both tracers and correlated with histopathology in 7/8 pts. In the 8th pt, PET/CT showed an omental cake.

Results Uptake and contrast resolution expressed by SUV and T/Bkg, respectively, is consistly higher with Chol than with Acet for BTCC, prostate involved by tumor and all LNs (Table). Although there was increased uptake of both tracers in all LNs, metastatic involvement was proven only in 1 LN. BTCC invaded the prostate in 2 pts and additional prostate carcinoma was seen in 2 other BTCC pts.

Conclusions Chol is a better tracer than Acet for PET/CT pre-operative evaluation and staging of BTCC, due to its higher uptake and contrast resolution. Further studies are required to assess the specificity of both tracers in LNs.