Reproducibility and repeatability of semiquantitative (18)F-fluorodihydrotestosterone uptake metrics in castration-resistant prostate cancer metastases: A prospective multicenter study Journal Article


Authors: Vargas, H. A.; Kramer, G. M.; Scott, A. M.; Weickhardt, A.; Meier, A. A.; Parada, N.; Beattie, B. J.; Humm, J. L.; Staton, K. D.; Zanzonico, P. B.; Lyashchenko, S. K.; Lewis, J. S.; Yaqub, M.; Sosa, R. E.; van den Eertwegh, A. J.; Davis, I. D.; Ackermann, U.; Pathmaraj, K.; Schuit, R. C.; Windhorst, A. D.; Chua, S.; Weber, W. A.; Larson, S. M.; Scher, H. I.; Lammertsma, A. A.; Hoekstra, O. S.; Morris, M. J.
Article Title: Reproducibility and repeatability of semiquantitative (18)F-fluorodihydrotestosterone uptake metrics in castration-resistant prostate cancer metastases: A prospective multicenter study
Abstract: 18F-fluorodihydrotestosterone (18F-FDHT) is a radiolabeled analog of the androgen receptor's primary ligand that is currently being credentialed as a biomarker for prognosis, response, and pharmacodynamic effects of new therapeutics. As part of the biomarker qualification process, we prospectively assessed its reproducibility and repeatability in men with metastatic castration-resistant prostate cancer. Methods: We conducted a prospective multiinstitutional study of metastatic castration-resistant prostate cancer patients undergoing 2 (test/retest) 18F-FDHT PET/CT scans on 2 consecutive days. Two independent readers evaluated all examinations and recorded SUVs, androgen receptor-positive tumor volumes, and total lesion uptake for the most avid lesion detected in each of 32 predefined anatomic regions. The relative absolute difference and reproducibility coefficient (RC) of each metric were calculated between the test and retest scans. Linear regression analyses, intraclass correlation coefficients (ICCs), and Bland-Altman plots were used to evaluate repeatability of 18F-FDHT metrics. The coefficient of variation and ICC were used to assess interobserver reproducibility. Results: Twenty-seven patients with 140 18FFDHT- avid regions were included. The best repeatability among 18F-FDHT uptake metrics was found for SUV metrics (SUVmax, SUVmean, and SUVpeak), with no significant differences in repeatability among them. Correlations between the test and retest scans were strong for all SUV metrics (R2 ≥ 0.92; ICC $ 0.97). The RCs of the SUV metrics ranged from 21.3% (SUVpeak) to 24.6%(SUVmax). The test and retest androgen receptor-positive tumor volumes and TLU, respectively, were highly correlated (R2 and ICC ≥ 0.97), although variability was significantly higher than that for SUV (RCs > 46.4%). The prostate-specific antigen levels, Gleason score, weight, and age did not affect repeatability, nor did total injected activity, uptake measurement time, or differences in uptake time between the 2 scans. Including the most avid lesion per patient, the 5 most avid lesions per patient, only lesions 4.2 mL or more, only lesions with an SUV of 4 g/mL or more, or normalizing of SUV to area under the parent plasma activity concentration-time curve did not significantly affect repeatability. All metrics showed high interobserver reproducibility (ICC > 0.98; coefficient of variation < 0.2%-10.8%). Conclusion: Uptake metrics derived from 18F-FDHT PET/CT show high repeatability and interobserver reproducibility. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging.
Keywords: reproducibility; prostate cancer; pet; fdht; repeatability
Journal Title: Journal of Nuclear Medicine
Volume: 59
Issue: 10
ISSN: 0161-5505
Publisher: Society of Nuclear Medicine  
Date Published: 2018-10-01
Start Page: 1516
End Page: 1523
Language: English
DOI: 10.2967/jnumed.117.206490
PUBMED: 29626121
PROVIDER: scopus
PMCID: PMC6167532
DOI/URL:
Notes: Article -- Export Date: 1 November 2018 -- Source: Scopus
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MSK Authors
  1. Michael Morris
    256 Morris
  2. John Laurence Humm
    337 Humm
  3. Pat B Zanzonico
    244 Zanzonico
  4. Jason S Lewis
    239 Lewis
  5. Steven M Larson
    736 Larson
  6. Howard Scher
    784 Scher
  7. Bradley Beattie
    105 Beattie
  8. Wolfgang Andreas Weber
    145 Weber
  9. Ramon Elias Sosa
    16 Sosa
  10. Kevin David Staton
    6 Staton
  11. Nicole Andrea Parada
    3 Parada
  12. Andreas Alexander Meier
    4 Meier