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

Abstract

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.