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Use of [11C]choline PET/CT in prostate cancer (CaP) imaging has demonstrated mixed results. The usefulness of labeled choline in cancer imaging is based upon the fact that the rate limiting enzyme choline kinase and the specific choline transporter are upregulated to support increased cell proliferation and concomitant membrane forming with major components being various phospholipids. Dr. Ludwig Rinnab and associates reported their experience with [11C]choline PET/CT staging of CaP in the online edition of the World Journal of Urology.

A retrospective study of 41 patients without evidence of lymph node or distant metastasis was performed. Mean age was 64.9 years and all had a rising PSA after radical prostatectomy (RP). Nine had received adjuvant radiotherapy and were identified by 3 consecutive rises in the PSA level. All patients had PSA measured on the day of [11C]choline PET/CT imaging and the mean was 2.8ng/ml. Imaging assessment was performed in a blinded fashion. TRUS was also performed in all patients.

In patients with pathological [11C]choline PET/CT uptake, PSA was 3.1ng/ml, and in those with a negative scan it was 0.86ng/ml. In 6 of 12 men with a PSA <1.5ng/ml, [11C]choline PET/CT showed a pathological uptake and a positive histology was found in 6/12 of these patients. In patients with a PSA between 1.5 and 2.5ng/ml, [11C]choline PET/CT showed a pathologic pattern in 16/16 and a positive histology was found in 12/16. In patients with a PSA between 2.5 and 5ng/ml, [11C]choline PET/CT showed a pathologic pattern in 8/8 and a positive histology was found in 7/8. In patients with a PSA greater than 5ng/ml, [11C]choline PET/CT showed a pathologic pattern in 5/5 and a positive histology was found in all. The sensitivity was 93% and the positive predictive value was 80%. The overall accuracy was 78%. The sensitivity for a PSA level <2/5ng/ml was 89%, with a specificity of 40%. Five patients had no [11C]choline PET/CT uptake and in 2 of these TRUS guided biopsy showed cancer. TRUS was suspicious in 26 patients and 20 had positive histology. Eleven other patients had a negative TRUS and 8 of them had a positive histology.

Source: UroToday