Good concordance between 11C-Choline PET-CT and bone scintigraphy for the detection of bone metastases from prostate cancer

38 Objectives To assess concordance between 11C-Choline PET-CT and Bone Scan(BS) for the detection of bone metastases(BM) in prostate cancer(PC) patients. Methods Sixty-two patients with PC were retrospectively evaluated. All underwent 11C-Choline PET-CT for initial staging(n=17;PSA:2.11-23.75ng/mL) or biochemical recurrence after radical treatment(surgery/radiation) in PC(n=45;PSA:1,6-25,0ng/mL). All patients underwent a BS with 99mTc-HDP within 30 days of the PET-CT. Eventual osseous uptake with 11C-Choline was analyzed, as well as skeletal morphological findings on CT, which were compared to BS findings. BM were defined by histopathological or clinical/radiological follow-up or demonstration of multifocal/bone marrow involvement. Results Fifty-eight studies with 11C-Choline and BS were concordant(93,6%). 43 studies were both negative. In six of them, BS detected benign lesions:1 osteoma,1 non-ossifying fibroma and 4 patients with Paget. None of them presented 11C-Choline uptake. 15 studies were both positive(bone uptake by BS and PET); however, no bone metastatic disease could be confirmed in 4 studies(no biopsy; inconclusive follow-up; no multifocal/bone marrow involvement). 4 of these 15 studies showed more BM in PET than in BS. 11C-Choline PET-CT identified BM which were not depicted by BS in 3 patients(4,8%), confirmed by follow-up in two patients and histology in the remaining patient. On the contrary, only in one patient(1,6%) with one solitary BM on distal tibia was depicted by BS, which was histopathologically confirmed, but was not shown on the PET-CT diagnostic field. All of bone lesions suspected to be metastases on CT had 11C-Choline and/or 99mTc-HDP uptake. Conclusions In our patient series with BM due to PC, a good concordance rate(93,6%) was observed between 11C-Choline PET-CT and BS, with 11C-Choline detecting more sites of metastatic bone involvement than BS and BS detecting more benign lesions than PET-CT