Radio-guided Surgery With DROP-IN Beta Probe for 68Ga-PSMA, in High-risk Prostate Cancer Patients Eligible for Robotic-assisted Radical Prostatectomy.

PSMA Radio-Guided Lymph Node Dissection With Beta-Probe, in High-risk Prostate Cancer Patients.

The goal of this observational study is to evaluate the diagnostic efficacy and the safety of the combined approach with β-probe and 68Ga-PSMA-11 PET/CT in the correct identification of lymph node metastases, in high-risk prostate cancer patients undergoing radical prostatectomy and pelvic lymph node dissection.

Study Phase: Phase II

Primary Objective:

To evaluate the diagnostic accuracy of the combined approach with β-probe and 68Ga-PSMA-11 PET/CT in the correct identification of lymph node metastases, in high-risk prostate cancer patients undergoing radical prostatectomy and pelvic lymph node dissection. The histopathological analysis of the surgical specimens will be considered the standard of reference and diagnostic accuracy will be evaluated in terms of sensitivity and specificity.

Secondary Objectives:

• the identification of the most appropriate tumor-to-background ratio (TBR) able to correctly locate the signal emitted by PSMA-positive lymph nodes compared with the signal derived by the background rumor.
• safety and toxicity analysis regarding the intraoperative application of the β-probe.
• the comparison between the signal detected by the β-probe and 68Ga-PSMA-11 PET/CT images.
• the correlation of the signal detected by the β-probe with the PSMA expression (PSMA staining) in lymph node metastases assessed by immuno-histochemical analysis on the surgical specimens

Drug Dosage, Formulation, Administration: Intravenous administration of 1.1 MBq/Kg of 68Ga-PSMA-11.

Primary Endpoint: Primary: sensitivity and specificity in a per-region analysis.

Secondary Endpoints:

• comparison of β-probe intra-operatory measurements with ex-vivo ones.
• comparison of β-probe measurements and 68Ga-PSMA-11 semi-quantitative parameters (SUVmax and PSMA-TV).
• comparison of β-probe measurements and PSMA expression assessed by IHC (PSMA staining).

Inclusion Criteria:

• Histologically proven prostate cancer
• High-risk prostate cancer (T>T2c and/or PSA>20 and/or ISUP>3)
• Patients suitable for radical prostatectomy + pelvic lymph node dissection
• 68Ga-PSMA-11 PET/CT performed within 4 weeks prior to surgery
• PSMA positive pelvic lymph nodes detected at 68Ga-PSMA-11 PET/CT
• Age >18 years old
• Willing to sign informed consent

Exclusion Criteria:

• Patient unfit for surgery
• M1 stage (any M) detected at 68Ga-PSMA-11 PET/CT or other imaging modalities performed during diagnostic wok-up evaluation
• Unable to tolerate PET scan