#0611

Assessing Biochemical Recurrence After Prostatectomy in Prostate Cancer Patients Using F-18-PSMA-1007 PET: Insights from Our Institute

Y. Huang¹, E. Huang¹, T. Wei¹, W. Huang¹, Y. Chang¹, H. Chung¹, T. Lin¹, C. Lin¹, T. Huang¹, W. Chen¹

¹Taipei Veterans General Hosptial, Urology, Taipei, Taiwan

Introduction:

Biochemical recurrence (BCR) in post-prostatectomy prostate cancer patients is often difficult to detect recurrent lesions using conventional imaging techniques such as CT or MRI. The use of PSMA PET has emerged as a novel diagnostic tool for identifying BCR. By utilizing F-18-PSMA-1007 PET, our institute has aimed to improve detection rates and better inform treatment strategies. In this presentation, we will share our experiences and insights gained from implementing this imaging technique.

Material and methods:

89 post-prostatectomy prostate cancer patients who experienced BCR or persistent prostate-specific antigen (PSA) from 2021 to 2022 were involved. All patients underwent conventional MRI and F-18-PSMA-1007 PET/MR scans to identify suspected recurrent lesions. We collected data from pathological reports of prostatectomy. Comparisons were made between the findings from conventional MRI and those from PSMA PET. Additionally, we gathered data on salvage treatments administered, and progression-free survival (PFS), defined as the absence of new recurrent lesions or PSA elevation after treatment. We also analyzed androgen deprivation therapy-free survival (ADT-FS) using life-table survival analysis.

Results:

The average time from prostatectomy to BCR was 28.53 months, and the PSA doubling time (PSADT) was 13.24 months. Pathological T stages were distributed as follows: T2 (31.5%, 28/88), T3a (42.7%, 38/88), and T3b (24.7%, 22/88). Pathological N stages were N0 (92%, 81/88) and N1 (8%, 7/88), with 34.1% (30/88) of patients having positive surgical margins (pT2:4, pT3a:15, pT3b:11). According to the European Association of Urology (EAU) criteria, 76.1% (67/88) of patients were classified as high-risk BCR cases. Conventional MRI positive results was 14.6% (13/89) and PSMA PET positive results was 76.4% (68/89). PSMA PET results were consistent with MRI findings in 9% (8/89) of patients, while PSMA PET detected more patients with positive findings than MRI in 67.4% (60/89) of cases. Patients received various salvage treatments: radiotherapy (RT) only (14.6%, 13/89), androgen deprivation therapy (ADT) only (15.7%, 14/89) with mean ADT duration of 23.57 months, and RT combined with concurrent ADT (60.7%, 54/89) with mean ADT duration of 11.54 months. The 1-year PFS was 99%, 2-year PFS was 94%, and 3-year PFS was 69%. The 1-year ADT-FS was 51%, 2-year ADT-FS was 33%, and 3-year ADT-FS was 13%.