Role of 18F-Choline PET/CT in Biochemically Relapsed Prostate Cancer After Radical Prostatectomy: Correlation With Trigger PSA, PSA Velocity, PSA Doubling Time, and Metastatic Distribution

Purpose The aim of this study was to evaluate the efficacy of 18F-choline PET/CT (18FCH-PET/CT) in restaging patients previously treated by radical prostatectomy for a prostate cancer, presenting with biochemical relapse during follow-up (FU). Patients and Methods Three hundred thirty-one patients referred to us from January 2009 to April 2011 to perform 18FCH PET/CT were evaluated: 233 of them (mean age 69.7 years) met the inclusion criteria of the study: (1) biochemical relapse after radical prostatectomy (trigger PSA >0.2 ng/mL) (n = 224) and (2) high risk for relapse (elevated Gleason score ≥8) in spite PSA <0.1 ng/mL during FU (n = 9). Trigger PSA was available for all patients (mean 8 ng/mL) and in 44 of them also PSA kinetic (PSA velocity—PSAvel; PSA doubling time—PSAdt). Correlation between 18FCH PET/CT detection rate and trigger PSA, PSAvel, PSAdt, and tumoral spread distribution were evaluated by univariate and multivariate analysis. Subsequent minimum FU was 1 year (mean 26 months, range 12–40). Results Overall detection rate of 18FCH PET/CT was 54%, which significantly increased when the trigger PSA increases (P < 0.001). PET-positive patients presented a “fast” PSA kinetic (mean PSAdt = 6 months and mean PSAvel = 9.3 ng/mL/yr), while PET-negative patients presented a “slow” PSA kinetic (mean PSAdt = 15.4 months and mean PSAvel = 0.9 ng/mL/yr). Disease relapse was local in 17% of cases, distant in 66%, and combined in 17%. Conclusions Overall 18FCH PET/CT detection rate was 54% (ie, similar to that reported in literature with 11C-choline), which increases with the increase in trigger PSA: this condition was particularly true in patients with accelerated PSA kinetic. In about 20% of patients, 18FCH PET/CT demonstrated local relapses early enough to offer locoregional radiation therapy.