99mTc-PSMA-I&S Biodistribution in Patients With Prostate Cancer

99mTc-PSMA-I&Amp;S in Patients With Prostate Cancer: An Exploratory Biodistribution Study With Histopathology Validation

This exploratory study conducted under the RDRC program studies the biodistribution of 99mTc-PSMA-I&S in patients with prostate cancer who undergo pelvic lymph node dissection. Prostate specific membrane antigen (PSMA)-targeted radio-guided surgery uses the preoperative intravenous administration of a PSMA-ligand called PSMA-imaging and surgery (I&S) labeled with the gamma-emitter radioisotope Technetium-99m (99mTc). Giving 99mTc-PSMA-I&S may detect PSMA-expressing lymph nodes during surgery using a gamma probe and may help guide doctors to detect prostate cancer that has spread to the lymph nodes.

PRIMARY OBJECTIVE: I. To define the biodistribution of 99mTc-based PSMA imaging and surgery agent (99mTc-PSMA-I&S) in normal and malignant tissues of patients with prostate cancer (PCa) with histopathology validation, when available. SECONDARY OBJECTIVES: I. To correlate the 99mTc-PSMA-I&S accumulation within tumor lesions observed by in-vivo single-photon emission computed tomography (SPECT), ex-vivo gamma measurements and level of prostate-specific membrane antigen (PSMA) expression quantified by histopathology, when available. II. To define the best time-point for radio-guided surgery (RGS) with the highest tumor-to-background ratio following 99mTc-PSMA-I&S administration. OUTLINE: The first 5 patients receive an initial dose of 99mTc-PSMA-I&S intravenously (IV) followed by 5 SPECT/CT scans at 3-5, 5-20, 17-21, 25-29, and 40-46 hours later. These 5 patients then receive a second dose of 99mTc-PSMA-I&S IV and then undergo standard of care surgery. All subsequent patients receive one dose of 99mTc-PSMA-I&S IV before surgery.

The first 5 patients receive an initial dose of undergo 99mTc-PSMA-I&S IV followed by 5 SPECT/CT scans at 3-5, 5-20, 17-21, 25-29, and 40-46 hours later. These 5 patients then receive a second dose of 99mTc-PSMA-I&S IV and then undergo standard of care surgery. All subsequent patients receive one dose of 99mTc-PSMA-I&S IV before standard of care surgery.

Medical Imaging, Single Photon Emission Computed Tomography, Single Photon Emission Tomography, single-photon emission computed tomography, SPECT, SPECT imaging, SPECT SCAN, SPET, tomography, emission computed, single photon, Tomography, Emission-Computed, Single-Photon

The biodistribution of 99mTc-PSMA-I&S in normal and malignant tissues of patients with prostate cancer will be measured by average and maximum standardized uptake value (SUVmean and SUVmax)

99mTc-PSMA-I&S accumulation within tumor lesions observed by in-vivo SPECT (SUVmean and SUVmax) will be correlated with ex-vivo gamma measurements (counts/minute) and level of PSMA expression quantified by histopathology (IHC score)

The best time-point for 99mTc-PSMA-I&S radioguided surgery will be determined by the tumor-to-background uptake ratio (TBR) using the time-activity curve function

Inclusion Criteria: Men with PCa (primary or recurrent disease) Men who received a 68Ga-PSMA-11 positron emission tomography (PET)/computed tomography (CT) for staging or restaging Men with evidence of lymph nodes (LNs)-positive disease on 68Ga-PSMA-11 PET/CT Men who are scheduled for pelvic LN dissection (PLND) Men who can provide oral and written informed consent Men who can comply with study procedures Exclusion Criteria: Patients who started any PCa treatment between study enrollment and surgery Technically inaccessible nodal location