Usefulness of 18F-fluoride PET/CT in Breast Cancer Patients with Osteosclerotic Bone Metastases

Bone metastasis is an important factor for the treatment and prognosis of breast cancer patients. Whole-body bone scintigraphy (WBBS) can evaluate skeletal metastases, and 18F-FDG PET/CT seems to exhibit high specificity and accuracy in detecting bone metastases. However, there is a limitation of 18F-FDG PET in assessing sclerotic bone metastases because some lesions may be undetectable. Recent studies showed that 18F-fluoride PET/CT is more sensitive than WBBS in detecting bone metastases. This study aims to evaluate the usefulness of 18F-fluoride PET/CT by comparing it with WBBS and 18F-FDG PET/CT in breast cancer patients with osteosclerotic skeletal metastases.Nine breast cancer patients with suspected bone metastases (9 females; mean age ± SD, 55.6 ± 10.0 years) underwent 99mTc-MDP WBBS, 18F-FDG PET/CT and 18F-fluoride PET/CT. Lesion-based analysis of five regions of the skeletons (skull, vertebral column, thoracic cage, pelvic bones and long bones of extremities) and patient-based analysis were performed.18F-fluoride PET/CT, 18F-FDG PET/CT and WBBS detected 49, 20 and 25 true metastases, respectively. Sensitivity, specificity, positive predictive value and negative predictive value of 18F-fluoride PET/CT were 94.2 %, 46.3 %, 57.7 % and 91.2 %, respectively. Most true metastatic lesions on 18F-fluoride PET/CT had osteosclerotic change (45/49, 91.8 %), and only four lesions showed osteolytic change. Most lesions on 18F-FDG PET/CT also demonstrated osteosclerotic change (17/20, 85.0 %) with three osteolytic lesions. All true metastatic lesions detected on WBBS and 18F-FDG PET/CT were identified on 18F-fluoride PET/CT.18F-fluoride PET/CT is superior to WBBS or 18F-FDG PET/CT in detecting osteosclerotic metastatic lesions. 18F-fluoride PET/CT might be useful in evaluating osteosclerotic metastases in breast cancer patients.