Traditionally imaging of prostate cancer has included ultrasound, CT of abdomen and pelvis, and bone scans. These examinations have a limited detection rate for patients with biochemical recurrence and prostate specific antigen (PSA) below 20 ng/mL. In 2016, guidelines by the European Association of Urology (EAU) and National Comprehensive Cancer Network (NCCN) changed and recommend use of radiolabeled choline PET/CT for selected patients with biochemical recurrence. Our review summarized present knowledge reported in 18 articles with 2 213 patients. Mean PSA at the time of the PET/CT was 3.6 ng/mL. Mean radiation activity was 561 MBq for 11C-choline PET/CT and 293 MBq for 18F-fluoro-choline PET/CT. Mean uptake time was 5 min with 11C-choline PET/CT and 29 min with 18F-fluoro-choline PET/CT. Overall, 1219 patients (55%) had positive findings with radiolabeled choline PET/CT. Mean detection rate of metastatic sites was 30% with 11C-choline PET/CT and 39% with 18F-fluoro-choline PET/CT but the difference was not statistically significant. Whereas 11C-choline and 18F-fluoro-choline differed regarding acquisition protocol due to differences in pharmacokinetics, detection rates with the two radiotracers did not differ markedly. In conclusion, radiolabeled choline PET/CT is more sensitive than conventional imaging. Radiolabeled choline PET/CT detected metastatic sites of recurrence in a third of the examined patients. These sites are not covered by standard salvage external beam radiotherapy for the prostate bed (SRT). The finding is an important biological reason for the frequent failure to standard SRT. Therefore, future may lead to a wider global use of PET/CT for restaging of biochemical recurrence.
Authors: Finn Edler von Eyben and Kalevi Kairemo