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Impact of 18F-DCFPyL PET on staging and treatment of unfavorable intermediate or high-risk prostate cancer

  • Adriano Basso Dias,
  • Antonio Finelli,
  • Glenn Bauman,
  • Patrick Veit-Haibach,
  • Alejandro Berlin,
  • Claudia Ortega,
  • Lisa Avery,
  • Ur Metser

Publication: Radiology, May 2022

Abstract

For primary staging of unfavorable intermediate or high-risk prostate cancer, 18F-DCFPyL PET helped to detect more nodal, distant metastases than did conventional imaging (bone scan, CT, and optional multiparametric MRI), altering treatment.

Background

Data regarding 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine 3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL) PET in primary staging of prostate cancer (PCa) are limited.

Purpose

To compare the performance of 18F-DCFPyL PET/CT or PET/MRI (PET) with bone scan and CT with or without multiparametric MRI (hereafter, referred to as conventional imaging) in the initial staging of men with unfavorable intermediate or high-risk PCa and to assess treatment change after PET.

Materials and Methods

This prospective study evaluated men with biopsy-proven, untreated, unfavorable intermediate or high-risk PCa with 0 to four metastases or equivocal for extensive metastases (more than four) who underwent PET between May 2018 and December 2020. The diagnostic performance of PET in detecting pelvic nodal and distant metastases was compared with conventional imaging alone. Metastatic sites at conventional imaging and PET were compared with a composite reference standard including histopathologic analysis, correlative imaging, and/or clinical and biochemical follow-up. The intended treatment before PET was compared with the treatment plan established after performing PET. Detection rate, sensitivity, and specificity of conventional imaging and PET were compared by using McNemar exact test on paired proportions.

Results

The study consisted of 108 men (median age, 66 years; IQR, 61–73 years) with no metastases (n = 84), with oligometastases (four or fewer metastases; 22 men), or with equivocal findings for extensive metastases (n = 2). Detection rates at PET and conventional imaging for nodal metastases were 34% (37 of 108) and 11% (12 of 108) (P < .001), respectively, and those for distant metastases were 22% (24 of 108) and 10% (11 of 108) (P = .02), respectively. PET altered stage in 43 of 108 (40%) and treatment in 24 of 108 (22%) men. The most frequent treatment change was from systemic to local-regional therapy in 10 of 108 (9%) and from local-regional to systemic therapy in nine of 108 (8%) men. Equivocal findings were encountered less frequently with PET (one of 108; 1%) than with conventional imaging (29 of 108; 27%).

Conclusion

Initial staging with 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine 3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL) PET after conventional imaging (bone scan and CT with or without multiparametric MRI) helped to detect more nodal and distant metastases than conventional imaging alone and changed treatment in 22% of men.
Clinical trial registration no. NCT03535831, NCT03718260