The accuracy of 99mTc-PSMA imaging in the re-staging and response monitoring in patients with metastatic prostate cancer

Concurrent 99mTc-HYNIC-PSMA-SPECT/CT and PSMA-PET baseline studies will be performed. Follow up studies will be performed at the time of standard of care restaging or whenever deemed necessary by the investigator. Standard clinical monitoring will continue during the study, as per the supervising medical oncologist direction. Routine tests would include PSA level at baseline and follow up visit at 12-14 weeks post study enrolment. Results obtained from both radiologic assessments would be compared for concordance and overall accuracy in determining treatment response. This will be compared against the overall clinical impression by the treating clinician based on all available data (including serum PSA). This is a pilot, single arm, comparative trial. Twenty men with prostate carcinoma who will be referred to our center for PSMA imaging will be included in the study. The indications for imaging will be recurrence evaluation or restaging. All patients will be fully informed about the procedures and probable use of data for research project and will sign a written consent. The study will be approved by local ethics committee. All patients will undergo 18F-DCFPyL PET/CT and 99mTc-HYNIC-PSMA SPECT/CT scans in a reasonably short time interval (< 1 week, whenever possible). In the day of the SPECT/CT scan a single administration of 740 +/- 111 MBq 99mTc(CO3)-HYNIC-PSMA will be given intravenously. Introduction of radiotracer may be followed by IV saline to flush the line and ensure complete dose is administered to patient. Three to four hours post-injection a SPECT/CT scan of the chest, abdomen and pelvis will be acquired. In the day of the PET/CT scan participants will be injected intravenously with 18F-DCFPyL and a scan will be perfomed 120-min following uptake period. Images will be reviewed separately and anonymously by two experienced nuclear physicians and will be categorized as normal or abnormal. Any non-physiologic uptake will be considered as abnormal finding. Any suspicious finding will be further evaluated by delayed imaging and post void images. In case of discrepancy between readers, consensus will be obtained by consulting with a third expert. Furthermore, the locations of abnormal uptake will be fully described in both sets of images with special attention on prostate bed, local or regional lymph nodes and skeletal system. Patients will remain in the trial from the time of the baseline 18F-DCFPyL PET/CT and 99mTc-HYNIC-PSMA SPECT/CT scans and until the time of restaging after 12-14 weeks from baseline Response assessment of 99mTc-HYNIC-PSMA SPECT/CT will be compared to F18-DCFPyL PET/CT, PSA levels and clinical assessment Clinical assessment, if appropriate, will be undertaken at baseline and over the entire study period as per standard of care follow-up by treating physicians. This will include checking for any signs of allergic reaction in addition to basic vital signs (blood pressure, heart rate, respiratory rate and temperature). Physical examinations may include the examination of the following: general appearance, eyes, ears, nose, throat, chest/cardiovascular/respiratory, gastrointestinal, musculoskeletal, thyroid/neck, lymph nodes, and neurological The trial investigators will permit trial-related monitoring, audits, and regulatory inspections, providing direct access to source data/documents. This may include, but not limited to, Human Research Ethics Committees and Institutional Governance Review Bodies. External monitoring will not be planned. However, the researchers will assess the data quality after 2 months from study start, to ensure that any major deficiencies are identified early in the study and rectified so as not to compromise the outcome of the study. The trial will be conducted in compliance with the protocol, Good Clinical Practice and regulatory requirements.