Endocrine Abstracts

Aim: To evaluate the use of PET/CT with ⁶⁴CuCl₂ in recurring prostate cancer after surgery in patients with low PSA level (<2).

Introduction: Previous works* demonstrated as ⁶⁴CuCl₂ is a PET probe in prostate cancer in mice with xenografts of prostate cancer.Moreover, it was described** in seven patients the role of ⁶⁴CuCl₂ PET/CT in staging of prostate cancer.

Method: 32 Patients with low PSA level (<2) in recurring prostate post-surgical cancer were studied with ⁶⁴CuCl₂ PET/CT executed at 1, 3 and 24 h after injection of 200–400 MBq (medium activity 4 MBq/kg). A dosimetric analysis was done with manual VOI on various organs (Liver, Kidneys, Spleen, lumbar spine L4-L5 and Prostate as target). Coregistered imaging with CT to calculate VOIs, specific activity (Bq/ml) and SUVmax were executed. We analyzed time/activity curve with Olinda/EXM software to calculate absorbed dose. All patients had a control of PSA 10 days after PET/CT scan.

Results: The PSA value was 1.1 ng/ml (0.4–1.9 ng/ml). All patients showed lesions with an uptake of ⁶⁴CuCl₂ with a ratio lesion/background grate than 10. The positive lesions (n=63) had a medium dimension of 5.2 mm (3–9 mm) in linfonodes (n=46), Prostatic lodge (n=13) and Bone (n=4). After 10 days all patients presented a reduction of PSA with a medium of 0.3 ng/ml (0.1–0.5). Sensibility 90%.

Conclusion: PET/CT scan with ⁶⁴CuCl₂ is a high sensitivity method to detect early recurring prostate cancer after surgery. The possibility to see the lesions in early stage and in low dimensions (3–9 mm) opens a new possibility for theranostic application. The reduction value of PSA after 10 days could be related to the therapeutic effect of ⁶⁴CuCl₂. When the lesions are very small, a diagnostic dose could be also therapeutic. Further studies are necessary, but this could be a new approach in theranostic application.

*F.Peng et al. – J.Nucl.Med. 2006; **E.Capasso et al. – Ann.Nucl.Med. 2015