engleski

The positivity rates of 18F-fluciclovine and 18F- choline PET/CT in men with recurrent prostate cancer

Prostate cancer recurrence detection is increasing due to improvement in positron emission tomography/computed tomography (PET/CT) imaging utilizing new tracers such as 18F-choline and 18F- fluciclovine. In Europe choline PET/CT has changed the management of prostate cancer, while in the USA fluciclovine PET/CT has shown promising results. The objective of this study is to evaluate the positivity rates of choline and fluciclovine for detecting prostate cancer recurrence in patients with similar levels of prostate-specific antigen (PSA). Subjects and Methods: We retrospectively assessed 111 18F- choline PET/CT scans and 147 18F-fluciclovine PET/CT scans of patients with suspected recurrent prostate cancer after initial treatment, obtained from two different academic institutions, one from Europe and the other from the USA. Patients were grouped according to their PSA levels, as follows: G1 (PSA<0.5), G2 (PSA≥0.5- 1), G3 (PSA≥1-2), G4 (PSA≥2-5), and G5 (PSA≥5). The positivity rates of both tracers were calculated for extraprostatic locations (overall and in bones only) in each group. Positivity rates for local recurrence were evaluated only for patients with prior prostatectomy. Evaluation of prostate cancer local recurrence in patients with preserved prostate was omitted, due to known high nonspecific tracer uptake and potential interpretation bias. A chi- square test was used to compare all positivity rates. Results: The overall extraprostatic positivity rates were 30% (G1, n=3/10), 27% (G2, n=3/11), 50% (G3, n=8/16), 56% (G4, n=19/34) and 80% (G5, n=32/40) for choline, and 39% (G1, n=14/36), 37% (G2, n=7/19), 60% (G3, n=9/15), 64% (G4, n=25/39) and 66% (G5, n=25/38), for fluciclovine. Positive bone lesions were found in 0% (G1, n=0/10), 0% (G2, n=0/11), 19% (G3, n=3/16), 24% (G4, n=8/34) and 50% (G5, n=20/40) of choline scans and in 11% (G1, n=4/36), 16% (G2, n=3/19), 33% (G3, n=5/15), 23% (G4, n=9/39) and 34% (G5, n=13/38) of fluciclovine scans. No significant difference in extraprostatic positivity rates was found between the two tracers (p>0.05). The local recurrence positivity rates among patient who underwent prostatectomy were 11% (G1, n=1/9), 0% (G2, n=0/9), 13% (G3, n=2/15), 25% (G4, n=4/16) and 11% (G5, n=2/19) for choline and 34% (G1, n=11/32), 22% (G2, n=4/18), 45% (G3, n=5/11), 53% (G4, n=10/19) and 50% (G5, n=6/12) for fluciclovine. Significant difference was found only in group G5, with higher positivity rates for fluciclovine scans (p=0.014). Conclusion: Both 18F-choline and 18F-fluciclovine PET/CT have high positivity rates for detecting extraprostatic lesions, with direct correlation of positivity rates and PSA levels. Overall, no significant difference between the two tracer positivity rates was found. However, population bias may have affected these data. Further intrapatient analysis should be performed

F-18-choline ; F-18-fluciclovine ; prostate cancer

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