Paramètres TEP/TDM à la 18F-Fluorocholine prédictifs de la toxicité hématologique du 223Radium dans les cancers prostatiques métastatiques osseux résistant à la castration

Abstract

Background223RadiumCl2 (223Ra) demonstrated in the study ASLYMPCA an improved median overall survival in patients with bone metastases and castration resistant prostate cancer. This treatment is expensive and carries a risk for hematologic toxicity. The main objective of our work was to study a biomarker on 18F-FCH PET/CT to predict the risk of hematological complications of 223Ra. The impact of 18F-FCH PET/CT on the initial management of 223Ra therapy was also investigated. Materials and MethodsEighteen patients were included in this retrospective study between January 2015 and June 2016. 18F-FCH PET/CT was performed before 223Ra therapy to evaluate contraindications. A new biomarker was developed: RVV (bone tumor volume/total bone volume). ResultsThe initial PET confirmed the possibility of treatment for 67 % of included patients. For the other 33 %, the cause of the exclusion was the presence of visceral metastasis or lymph node(s) (50 %), extensive bone disease (17 %) or both (33 %). Five patients had hematological toxicity, one grade 3, five grade 1–2. RVV was correlated with the decrease in hemoglobin (r=0.88; P=0.004) and to thrombocyte decrease (r=0.68; P=0.06). The best cut-off to prevent hematologic toxicities was RVV=7.1 which means 7.1 % of tumoral bone. ConclusionBaseline 18F-FCH PET/CT allow patient selection for 223Ra. RVV could be an efficient biomarker of hematological toxicity of 223Ra.