Initial clinical experience of radioactive iodine-125 permanent interstitial implantation for prostate cancer was presented. We reviewed dose volume histogram (DVH) data and prostate specific antigen (PSA) data, and adverse events of 53 patients who were treated by brachytherapy from October 2005 to March 2007. Twelve patients were treated with combined therapy of external body radiotherapy of 45 Gy because of intermediate risk (EBRT group), and 41 were treated only with brachytherapy (monotherapy group). Mean V100 was 93.1 %, D90 was 158.2 Gy in the monotherapy group, and 91.6 %, 115.6 Gy in the EBRT group. Migration of iodine-125 occurred in 21 patients (39.6%). DVH data of patients with migration were lower than that without migration (V100: 90.8 %, D90; 149.4 Gy vs. V100: 94.0%, D90: 161.5 Gy, respectively) (p<0.05), No severe early adverse event occurred. Serum PSA level in all patients began to decrease by 3 months after the implantation of the iodine. Our initial data of iodine-125 brachytherapy for prostate cancer is satisfactory, but longer follow up is required for further confirmation.

2005年10月,当院は山陰で初めて前立腺癌のヨウ素125密封小線源永久挿入療法を導入した。2007年3月までに53例(単独治療41例,外照射併用12例)を経験したので初期成績を報告する。Dose volume histogram(DVH)のうちV100, D90の平均値は単独治療群93.1% 158.2Gy, 併用治療群91.6%, 115.6Gyだった。21例(39.6%)で線源の前立腺外移動が見られた。線源移動群のDVHデータ(V100: 90.8%, D90: 149.4Gy)は移動なし群(V100: 94.0%, D90: 161.5 Gy)に比べ不良であった(p<0.05)。重篤な急性期有害事象は認めず.前立腺特異抗原は全例低下を認めた。DVHデータおよび臨床データは満足できる結果であった。今後.線源移動の発生要因の検討に加え,さらに症例を重ねて長期成績を検討することが必要である。