Prospective Evaluation of 18 F-DCFPyL PET/CT in Biochemically Recurrent Prostate Cancer in an Academic Center: A Focus on Disease Localization and Changes in Management.

¹⁸ F-DCFPyL (2-(3-{1-carboxy-5-[(6- ¹⁸ F-fluoropyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid) is a promising PET radiopharmaceutical targeting prostate-specific membrane antigen (PSMA). We present our experience with this single-academic-center prospective study evaluating the positivity rate of ¹⁸ F-DCFPyL PET/CT in patients with biochemical recurrence (BCR) of prostate cancer (PC). Methods: We prospectively enrolled 72 men (52-91 y old; mean ± SD, 71.5 ± 7.2) with BCR after primary definitive treatment with prostatectomy ( n = 42) or radiotherapy ( n = 30). The presence of lesions compatible with PC was evaluated by 2 independent readers. Fifty-nine patients had scans concurrent with at least one other conventional scan: bone scanning (24), CT (21), MR (20), ¹⁸ F-fluciclovine PET/CT (18), or ¹⁸ F-NaF PET (14). Findings from ¹⁸ F-DCFPyL PET/CT were compared with those from other modalities. Impact on patient management based on ¹⁸ F-DCFPyL PET/CT was recorded from clinical chart review. Results: ¹⁸ F-DCFPyL PET/CT had an overall positivity rate of 85%, which increased with higher prostate-specific antigen (PSA) levels (ng/mL): 50% (PSA < 0.5), 69% (0.5 ≤ PSA < 1), 100% (1 ≤ PSA < 2), 91% (2 ≤ PSA < 5), and 96% (PSA ≥ 5). ¹⁸ F-DCFPyL PET detected more lesions than conventional imaging. For anatomic imaging, 20 of 41 (49%) CT or MRI scans had findings congruent with ¹⁸ F-DCFPyL, whereas ¹⁸ F-DCFPyL PET was positive in 17 of 41 (41%) cases with negative CT or MRI findings. For bone imaging, 26 of 38 (68%) bone or ¹⁸ F-NaF PET scans were congruent with ¹⁸ F-DCFPyL PET, whereas ¹⁸ F-DCFPyL PET localized bone lesions in 8 of 38 (21%) patients with negative results on bone or ¹⁸ F-NaF PET scans. In 8 of 18 (44%) patients, ¹⁸ F-fluciclovine PET had located the same lesions as did ¹⁸ F-DCFPyL PET, whereas 5 of 18 (28%) patients with negative ¹⁸ F-fluciclovine findings had positive ¹⁸ F-DCFPyL PET findings and 1 of 18 (6%) patients with negative ¹⁸ F-DCFPyL findings had uptake in the prostate bed on ¹⁸ F-fluciclovine PET. In the remaining 4 of 18 (22%) patients, ¹⁸ F-DCFPyL and ¹⁸ F-fluciclovine scans showed different lesions. Lastly, 43 of 72 (60%) patients had treatment changes after ¹⁸ F-DCFPyL PET and, most noticeably, 17 of these patients (24% total) had lesion localization only on ¹⁸ F-DCFPyL PET, despite negative results on conventional imaging. Conclusion: ¹⁸ F-DCFPyL PET/CT is a promising diagnostic tool in the work-up of biochemically recurrent PC, given the high positivity rate as compared with Food and Drug Administration-approved currently available imaging modalities and its impact on clinical management in 60% of patients.
(© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)