[18F]Florastamin PET/CT Imaging Examination in Patients With Suspected Recurrent or Metastatic Prostate Cancer

In this study, the diagnostic efficacy of \[18F\]Florastamin PET/CT imaging at detecting recurrent or metastatic prostate cancer will be evaluated according to the histopathology truth standard in prostate cancer patients whose recurrent or metastatic lesions have been confirmed with the conventional imaging. Patients who meet the inclusion/exclusion criteria of the clinical study protocol will be enrolled, who then will undergo a biopsy or pelvic lymph node dissection (PLND) for one or more lesion locations confirmed with the conventional imaging within 28 days from \[18F\]Florastamin PET/CT scanning. After the biopsy or PLND, follow-up will be carried out for 2 weeks. However, if necessary, based on the judgment of the principal investigator, additional visits may be made. 1. Baseline Procedures At the baseline visit, the conventional imaging will be performed. The results of whole-body bone scan and gadolinium-enhanced MRI (for the chest, abdomen or pelvis) within 6 weeks prior to \[18F\]Florastamin PET/CT scanning will be collected. All conventional imaging examinations will be evaluated by the study site. At the time of whole-body bone scanning, examinations will be performed 2 hours after the contrast agent 99mTc-HDP 20 to 30 mCi is administered intravenously. At the time of gadolinium-enhanced MRI scanning (for the chest, abdomen or pelvis), the gadolinium contrast agent (Gadobrix 1 cc/kg) will be administered intravenously. 2. Biopsy and PLND Images collected through the conventional imaging during the baseline visit can be selectively used for images to guide a biopsy, and images to decide on biopsy sites will be read by the study site. If more than one legions are identified through the image reading, an intermediary radiology specialist will choose a lesion for which to perform a biopsy; however, among the lesions identified, the one determined to be safe for the subject in the investigator's judgment will be preferred as a site on which to perform a biopsy or PLND, and the final biopsy site will be decided after checking its justification through consultation with the intermediary Department of Radiology. A biopsy can be performed while hospitalized, if necessary. Pelvic lymph node dissection (PLND) is surgery to remove the lymph nodes from the pelvis, which is part of a radical prostatectomy, so it is typically performed with hospitalization. 3. Florastamin PET imaging (PSMA-PET Imaging) Uptake values of \[18F\]Florastamin in the region of interest (ROI) of Florastamin PET imaging are evaluated by an independent evaluator. The independent evaluator records all uptake values observed in the lesion, and analyzes uptake values in the lesion where the biopsy has been performed during analysis of efficacy evaluation. 4. Biopsy and Histopathology Tissues removed through a biopsy or PLND are delivered to the Department of Pathology in accordance with the guidelines of the study site and slides by biopsy or PLND site are produced. A pathologist at the study site performs histopathological evaluation of the slides produced with blinded to results of \[18F\]Florastamin PET/CT examinations. An area on which a biopsy or PLND has been performed and histopathological results thereof are collected in the eCRF. 5. Histopathology truth standard Tissues removed with a standard method in more than one lesion locations confirmed by the conventional imaging performed prior to \[18F\]Florastamin PET/CT scanning are evaluated in terms of whether there is prostate cancer, there are any other tumors, it is impossible to read, etc. In addition, the positive/negative result of \[18F\]Florastamin PET/CT imaging in the applicable location is evaluated by an independent evaluator.