RT Journal Article SR Electronic T1 Feasibility of use of the xSPECT-QUANT® tool for therapeutic response assessment of bone metastatic prostate cancer. JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1791 OP 1791 VO 56 IS supplement 3 A1 Romain De Laroche A1 Philippe Robin A1 Pierre-Yves Le Roux A1 Solene Querellou A1 David Bourhis A1 Jean Malhaire A1 Pierre Salaun A1 Ronan Abgral YR 2015 UL http://jnm.snmjournals.org/content/56/supplement_3/1791.abstract AB 1791 Objectives Therapeutic response assessment is a major challenge in patients with bone metastatic prostate carcinoma (BMPC). BMPC progression criteria (PCWG 2, 2007) take into account serum PSA level changes or appearance of 2 or more new bone scan lesions. However, interpretation with visual analysis on SPECT-CT limits its performance, making difficult an objective response evaluation. The aim of this prospective study is to assess the feasibility to use a SPECT-CT quantification method for BMPC response evaluation.Methods Patients with castrate-resistant BMPC treated by abiraterone (Zytiga®) were included. All patients underwent 2 SPECT-CT (Symbia, Intevo, Siemens®): baseline (M0) and at 3 months of treatment (M3). SUVmax and SUVpeak quantification were performed using the xSPECT-QUANT® tool on the highest uptake target lesions (maximum of 5). Criteria used for response evaluation were arbitrarily the same used in PET-CT for solid cancers (EORTC99 and PERCIST1.0). Results were compared with serum PSA level changes.Results Seven patients aged of 72,4 +/- 8,7 years were included from April to October 2014. 2Two patients died before M3. The mean delay between the 2 SPECT-CT was 3,7 +/- 0,5 months. The mean SUVmax and SUVpeak on target lesions were respectively 29,0 and 25,1 on M0 and 15,5 and 13,4 on M3. Two, 2 and 1 patients were respectively in partial response (PR), stable disease (SD) and progressive disease (PD) according to EORTC99. One, 3 and 1 patients were respectively in PR, SD and PD according to PERCIST1.0. Three and 2 response evaluations according to EORTC99 and PERCIST1.0 were respectively matched with serum PSA level changes.Conclusions These preliminary results show the feasibility to use the xSPECT QUANT® tool in bone scan for the response evaluation of BMPC treated by Zytiga®.