Fluoride-18F PET/CT to evaluate effectiveness of treatment of metastatic prostate cancer with Ra-223

Abstract

Bone metastases from patients with prostate cancer are the greatest cause of death, reduction of quality of life and elevated treatment costs. Radium-223 dichloride or Ra223Cl2 is an alpha-emitting radioisotope (95%) of approximately 28 MeV. This radiotracer mimics calcium, which is an integral part of bone metabolism. Therapy with Ra223Cl2 (Ra-223) in patients with metastatic prostate cancer has demonstrated increased survival. However, a significant number of patients do not respond to treatment and the early identification of these patients is important to avoid inefficient and morbid therapies at elevated costs. Molecular whole-body bone imaging with 18F-fluoride PET/CT (F-18 PET/CT) is a highly sensitive method in identifying osteoblastic metastatic lesions in prostate cancer patients. Objective: Evaluate which patients most benefit from treatment with Ra-223 by using whole-body bone imaging with F-18 PET/CT. Methods: Patients with prostate cancer metastatic to bones and without visceral lesions will be submitted to treatment with Ra-223. All patients will perform F-18 PET/CT images. These images will be undertaken at 3 different time intervals: before, during and 6 months after the end of treatment with Ra-223. The clinical criteria such as pain relief, quality of life and survival (according to the form provided by the Institution) will be correlated to the F-18 PET/CT images. It is expected that F-18 PET/CT is capable of identifying which patients most benefit from this treatment. This study has not been described in the literature as of today. (AU)