The ability of 18F-choline PET/CT to identify local recurrence of prostate cancer

Abdom Imaging. 2015 Oct;40(8):3230-7. doi: 10.1007/s00261-015-0547-0.

Abstract

Purpose: To determine when 18F-choline PET/CT can truly identify local recurrence of prostate cancer.

Methods: 1031 patients from 3 European centers underwent (18)F-choline PET/CT (FCH PET/CT) for recurrent disease; 131 subjects (12.7%) showed a positive FCH uptake in the prostatic gland or prostatic fossa. Median age was 72 years (range 48-87 years), and the median PSA level at the time of FCH PET/CT scan was 4.41 ng/mL (0.22-18.13 ng/mL). 45 patients (34.4%) had a Gleason score (GS) >7, and the residual subjects had a GS ≤ 7. The assessment of true or false-positive FCH PET/CT findings was made by magnetic resonance imaging (n = 34) and/or biopsy in 75/131 cases. A χ (2) test and a Z Kolmogorov-Smirnov test were used to assess the correlation between clinical variables (age, PSA, GS, type of therapy) and FCH PET/CT findings.

Results: FCH PET/CT resulted truly positive (TP) for recurrent disease in the prostatic gland/fossa in 59/75 patients (79%) and falsely positive (FP) in 16 subjects (21%). The median value of PSA at the time of FCH PET/CT scan was higher in TP as compared to FP, although not statistically significant (4.76 vs. 3.04 ng/mL p > 0.05). Similarly, median age, GS categories, and the type of therapy were similar between the two groups (p > 0.05). However, when matching GS categories and PSA values, we found that the number of patients with TP findings were higher in the case of a PSA > 2 ng/mL, independently from the GS (ranging between 74% and 92%). Conversely, FP rate ranged between 50% and 65% in patients with a PSA ≤ 2 ng/mL, especially in the case of GS ≤ 7, whereas FP was around 25% in those with a GS >7 and PSA > 2 ng/mL.

Conclusions: FCH PET/CT has a limited role in evaluation of prostatic gland/fossa recurrence, due to the physiological biodistribution of the radiopharmaceutical agent. However, in 70-90% of patients with a PSA >2 ng/mL, independently from GS, a focal FCH uptake is compatible with a true local recurrence.

Keywords: 18F-choline PET/CT; False positive; Prostate cancer recurrence; Salvage treatments; True positive.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Choline / analogs & derivatives*
  • Humans
  • Male
  • Middle Aged
  • Multimodal Imaging*
  • Neoplasm Recurrence, Local / diagnosis*
  • Positron-Emission Tomography*
  • Prostate / diagnostic imaging
  • Prostatic Neoplasms / diagnosis*
  • Radiopharmaceuticals
  • Reproducibility of Results
  • Retrospective Studies
  • Tomography, X-Ray Computed*

Substances

  • Radiopharmaceuticals
  • fluoromethylcholine
  • Choline