PETによる前立腺癌の評価

Abstract

前立腺癌症例54例および前立腺肥大症6症例を対照群とし, FDG-PETを施行した.FDG-PETによる前立腺癌病巣の検出率は, 原発巣において70%であり, 又, 転移巣の検出精度も従来の画像診断法を凌駕するものではなかった.前立腺癌の早期発見や転移巣の検出目的ではその有用性は低いと考えられるが, 前立腺原発巣におけるFDGの集積を定量的に評価・解析すると, その測定値(SUV)は, 組織学的悪性度・臨床病期・PSA等の臨床病理学的パラメーターと相関を示した.又, 内分泌治療後のFDG-PETでは, 細胞増殖活性の低下を反映してSUVの有意な減少を認めた.更にSUVが高値の症例は治療後の再発・再燃の可能性が高いことも示唆された.以上の結果から, FDG-PETにより前立腺癌の生物学的悪性度を評価することが可能と考えられ, 予後予測因子としての有用性が示唆された

The clinical usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was examined in 54 patients with prostate cancer. FDG accumulation was positive in 38 of 54 the prostates (70%), 3 of 8 the lymph node metastases (38%) and 10 of 16 the bone metastases (63%), which suggested that FDG-PET is not superior to other conventional imaging methods as a tool for tumor detection. On the other hand, a quantitative value for FDG uptake in the prostate, expressed as a standardized uptake value (SUV), significantly correlated to the histological grade, clinical stage and serum PSA of the patients. A decrease of SUV was observed in all the patients who responded to endocrine treatment, and the patients with high pre-treatment SUV were shown to be at the risk for disease progression after initial treatment. The present results indicated that FDG-PET could provide us with useful prognostic information for the patients with prostate cancer by evaluating the malignant potential of the tumor.