Prostatectomy

Biology

Prostate cancer

Urology

Radiation therapy

Paleontology

Stage (stratigraphy)

Biochemical recurrence

Internal medicine

Prospective cohort study

Medicine

Nuclear medicine

Cancer

Journal of Nuclear Medicine

1566 null Aim: null null A complete biochemical response immediately after radical prostatectomy (RP) is an indicator of optimal prostate cancer (PCa) control. However, patients with persistent high PSA levels after RP showed less favourable cancer control and survival rates over time. Thus, the precise localization of residual disease after RP is crucial for improving patients’ outcome.The primary aim of this study was to assess the role of 68Ga-PSMA-11 PET/CT for detecting PCa location(s) in patients with biochemical persistence (BCP) after RP. Secondary aim was to evaluate its impact on adjuvant radiotherapy (ART) or salvage radiotherapy (SRT) planning. null Methods: null null 68Ga-PSMA-11 PET/CT is performed in our institution through a prospective, single-center, open-label study approved by local ethical committee (prot. P-5315). Two hundred-eleven PCa patients were referred to our center from November 2016 to December 2018. We performed a retrospective sub-analysis in BCP patients matching these inclusion criteria: 1) RP as primary therapy; 2) PSA-nadir >0.1 ng/mL at 8 weeks after RP; 3) No adjuvant/salvage therapy or hormonal-therapy (ADT) performed after RP; 4) PET scan performed within 12 months from RP.Twenty-one patients matched these criteria and were considered in this analysis (median age 69.6 years; range 52-80). Patients presented with International Society of Urological Pathology (ISUP) grade null =4 (n=13/21), stage >=pT3a (n=11/21), pN1 (n=3/21) and R1 disease (n=9/21), respectively. Median/mean PSA-nadir were 0.2/0.5 +- 0.7 ng/mL (range 0.1-3.3); median/mean PSA doubling time were 3.1/4.7 +- 4.7 months (range 0.6-19.4); median/mean PSA velocity were 0.8/6.5 +- 11.8 ng/mL/year (range 0-30.2). null Results: null null 68Ga-PSMA-11 PET/CT detection rate was 52.3% (CI95% 32.4%-71.7%). Median/mean PSA at the time of PET scan were 0.5/1.3 +- 2.1 ng/mL (range 0.21-8.9). Locally confined disease only (prostate bed) was detected in 4.7% of cases, pelvic nodes were detected in 14.3%, while at least one distant lesion (extra-pelvic nodes and/or bone lesions) was detected in 33.3%. ART/SRT in prostate bed was the intended treatment before PET scan in all cases.ART/SRT plan was reviewed in a tumor board integrating 68Ga-PSMA-11 PET/CT results. ART/SRT planning was confirmed as intended before PET scan in 11/21 patients (10 PET negative and 1 PET positive with prostate bed relapse). 3/21 performed ART/SRT in prostate bed and additional stereotactic radiotherapy on PET positive findings. ART/SRT was aborted in 3/21 patients and ADT was administrated instead of ART/SRT. In 1/21 case ART/SRT was aborted and pelvic lymph-node dissection was performed. In 3/21 cases ART/SRT planned target volume was modified including only PET positive pelvic nodes withouth standard radiotherapy in prostate bed. null Conclusions: null null In this patient-series, 68Ga-PSMA-11 PET/CT proved its role in BCP setting detecting disease outside prostate bed in 47.6% of cases. In these patients adjuvant/salvage therapy plan was modified due to the integration of 68Ga-PSMA-11 PET/CT results into the decision-making process. These data may suggest the presence of extended disease not detected by conventional imaging prior to surgery and highlight the importance of PET imaging in BCP setting.

68Ga-PSMA-11 PET/CT in prostate cancer patients with biochemical persitence after radical prostatectomy. Detection of cancer locations and impact on subsequent therapy.