LAUSR

Introduction Positron Emission Tomography (PET-CT) with 18F-choline is an important tool in diagnosis and visualisation of prostate cancer metastases (PCM). However, the diagnostic value of quantitative PET parameters, including Standardised Uptake Values (SUVmax) in patients with PCM is uncertain. The purpose of our study was to access the possible differences in SUVmax between subgroup of patients with prostate cancer with metastases in various locations. Material and methods A retrospective analysis of 172 consecutive patients with diagnosed prostate cancer with metastases undergoing a control PET-CT study was performed. PET-CT was performed using Discovery IQ scanner (GE Healthcare), 3 and 20 min after injection of 18F-choline (3 MBq/kg). Metastases locations were assessed by visual estimation during PET-CT scan, SUVmax was calculated in most metabolically active regions and analysed together with PSA levels and PSA change per month. Data are given as median values (quartiles), p values as assessed by Kruskal-Wallis ANOVA. Results and discussions Out of the cohort study, in 84 patients metastases were found in lymph nodes only (group A), in 38 in bones only (group B) and in 50 in both lymph nodes and bones (group C). No statistically significant differences between the groups were observed in Prostate Specific Antigen (PSA) levels at the time of diagnosis: 21,40 (10,61;45,80) ng/ml; 33,58 (7,00;790,00) ng/ml and 29, 10 (12,90;116,50) ng/ml, at the time of PET-CT scan: 4,07 (1,94;12,12) ng/ml; 5,62 (1,27;22,08) ng/ml and 8,71 (3,00;27,30) ng/ml, as well as at its change per month: 0,37 (0,07;1,78) ng/ml/month; 0,17 (0,03;1,95) and 0,91 (0,08; 3,77) ng/ml/month, for groups A, B and C, respectively. However, the SUVmax was significantly higher in patients with multiple metastases localizations (groups C) as compared to groups A and B: 5,70 (4,20;8,30) ng/ml vs 3,75 (2,40;5,64) ng/ml and 3,80 (2,50;6,80) ng/ml. Conclusion In patients with widely-spread prostate cancer (metastases to lymph nodes and bones) SUVmax levels are higher than in patients with metastases to lymph nodes only or to bones only, despite similar PSA and its change in time.