目的：評估中高風險度攝護腺癌病人接受螺旋刀或銳速刀之影像導引強度調控放射治療的生化 無復發率及治療副作用之初步結果。 材料與方法：2008 年 4 月至 2012 年 10 月，共 72 位有中高風險度攝護腺癌且無遠端轉移之病 患於本科接受影像導引強度調控放射治療。年齡範圍介於 58 至 89 歲，平均年齡為 73 歲。23 位為中風險度，49 位為高風險度。分別有 51 位接受螺旋刀治療，21 位接受銳速刀治療。病人 接受治療的平均劑量為 74 Gy。20 位只接受放射線治療而有 52 位接受放射線合併賀爾蒙治療。 生物化學失敗的臨床定義是採用血液中測得的攝護腺特異抗原值大於最低值加 2 ng/mL。治療後 攝護腺特異抗原最低值以 0.2 ng/mL 為閾值或以出現暫時性反升前最低值為標準。治療副作用依 照常見不良事件評價標準第三版（CTCAE v.3.0）來評估。 結果：平均追蹤時間 28 個月。4 位病患有生物化學失敗。在只接受放射線治療及接受放射線 合併賀爾蒙治療的兩群病患中，放射治療後到達最低攝護腺特異抗原值的時間分別為 15.58 及 5.73 個月（p = 0.001）。所有病患的放射線療程皆無中斷。43 位病人（59.7%）產生急性第一 級泌尿道症狀，4 位病人（5.6%）產生急性第二級泌尿道症狀，無病人有急性第三級以上泌尿 道症狀。25 位病人（34.7%）產生急性第一級腸胃道症狀，無病人有急性第二級以上腸胃道症 狀。兩位病患在放射治療 20 個月後左右被診斷出有放射治療後直腸炎。 結論：影像導引強度調控放射治療針對中高風險度攝護腺癌病人為一種有效且易接受的治療。 而我們也觀察到放射線合併賀爾蒙治療的這群病患中，有比只接受放射線治療更好的生物化學 控制率。然而尚須要更長的追蹤時間以比較結果。

Purpose : To evaluate the preliminary outcome of curative image-guided radiotherapy (IGRT) with Helical Tomotherapy or RapidArc for patients with intermediate- to highrisk prostate cancer. Materials and Methods : Between April 2008 and October 2012, 72 patients with pathologically proven prostate adenocarcinoma were included. Age ranged from 58 to 89 with mean age of 73 years. Twenty-three patients were intermediate-risk group and 49 were high-risk group. Fifty-one and 21 patients were treated with Helical Tomotherapy and RapidArc respectively. The mean radiation dose was 74 Gy. Twenty patients were treated with external beam radiation therapy alone (EBRT-only group) and 52 were treated with EBRT plus androgen deprivation therapy (EBRT-ADT group). The biochemical failure was defined by a rise of 2 ng/mL or more above the nadir prostate specific antigen (PSA). The nadir was defined as lowest PSA value preceding a given threshold of 0.2 ng/mL or as absolutely lowest PSA before the transient bounce. Toxicities were assessed and documented in agreement with the Common Terminology Criteria for Adverse Events version 3 (CTCAE v.3.0). Results : With the mean follow-up period of 28 months, four patients (5%, 4/72) had biochemical failure. The mean time interval to achieve the nadir PSA (TnPSA) in the EBRT-only group and EBRT-ADT group were 15.58 months and 5.73 months respectively (p = 0.001). All patients tolerated IGRT without any interruption. The patients exhibited grades 1 and 2 levels of acute genitourinary toxicities at 59.7% (43/72) and 5.6% (4/72). Grade 1 acute gastrointestinal toxicity was 34.7% (25/72). As for late toxicity, two patients developed grade 2 radiation proctitis 20 months after EBRT. Conclusion : IGRT for patients with intermediate- to high-risk prostate cancer was an effective and well-tolerated treatment. The EBRT-ADT group had better biochemical control than the EBRT-only group. Longer follow-up period was necessary.