Value of F-Choline PET/MRI hybrid technique on the therapeutic approach for patients with prostate cancer treated with prostatectomy and rising prostate specific antigen levels below 1 ng/ml.

Objective: To assess the detection rate of F-Choline PET/MRI and subsequent changes in therapy approach for patients with prostate cancer treated by prostatectomy and with rising levels of PSA <1 ng/ml.

Methods: Prospective study with our first 36 patients with prostatectomy for prostate cancer and rising levels of PSA, who were referred for an F-Choline PET/MRI study. A dual-phase study was acquired after intravenous administration of 185±10% MBq of F-Choline: 1) early imaging (immediately after tracer administration) of prostate area (emission PET/Multiparametric MRI). 2) whole-body imaging 1 h after tracer injection (emission PET/MRI: T1, T2, STIR, diffusion). The therapy approach for patients was decided upon the Oncology Committee consensus based on F-Choline PET/MRI findings.

Results: Twenty out of 36 patients (55.6%) were positive for the F-Choline PET/MRI study: 8 (22.2%) within the prostatectomy bed, 7 (19.4%) with infradiaphragmatic lymph nodes, 4 (11.1%) with local recurrence and infradiaphragmatic lymph nodes, and 1 (2.8%) with bone metastasis. Sixteen out of the 36 patients (44.4%) were negative for the F-Choline PET/MRI study. F-Choline PET/MRI findings had an impact on the therapy approach to follow: 15 patients (41.6%) showed oligometastatic disease which was treated by imaging-guided radiotherapy, 5 (13.9%) with multiple metastatic disease were treated by androgen deprivation therapy, 16 (44.4%) negative were under active surveillance.

Conclusion: Hybrid F-Choline PET/MRI procedure showed a high detection rate for recurrence in prostate cancer patients treated with prostatectomy and rising PSA levels <1 ng/ml, and F-Choline PET/MRI findings resulted in a better tailored therapy approach delivered to our patients.