Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie, Technische Universität München, Ismaninger Str. 22, 81675, München, Germany.
Strahlenther Onkol. 2012 May;188(5):410-6. doi: 10.1007/s00066-012-0081-8. Epub 2012 Feb 26.
The goal of this work was to assess the feasibility of moderately hypofractionated simultaneous integrated-boost intensity-modulated radiotherapy (SIB-IMRT) with helical tomotherapy in patients with localized prostate cancer regarding acute side effects and dose-volume histogram data (DVH data).
Acute side effects and DVH data were evaluated of the first 40 intermediate risk prostate cancer patients treated with a definitive daily image-guided SIB-IMRT protocol via helical tomotherapy in our department. The planning target volume including the prostate and the base of the seminal vesicles with safety margins was treated with 70 Gy in 35 fractions. The boost volume containing the prostate and 3 mm safety margins (5 mm craniocaudal) was treated as SIB to a total dose of 76 Gy (2.17 Gy per fraction). Planning constraints for the anterior rectal wall were set in order not to exceed the dose of 76 Gy prescribed to the boost volume. Acute toxicity was evaluated prospectively using a modified CTCAE (Common Terminology Criteria for Adverse Events) score.
SIB-IMRT allowed good rectal sparing, although the full boost dose was permitted to the anterior rectal wall. Median rectum dose was 38 Gy in all patients and the median volumes receiving at least 65 Gy (V65), 70 Gy (V70), and 75 Gy (V75) were 13.5%, 9%, and 3%, respectively. No grade 4 toxicity was observed. Acute grade 3 toxicity was observed in 20% of patients involving nocturia only. Grade 2 acute intestinal and urological side effects occurred in 25% and 57.5%, respectively. No correlation was found between acute toxicity and the DVH data.
This institutional SIB-IMRT protocol using daily image guidance as a precondition for smaller safety margins allows dose escalation to the prostate without increasing acute toxicity.
本研究旨在评估局部前列腺癌患者采用螺旋断层调强放疗（tomotherapy）实施适度低分割同步推量调强放疗（SIB-IMRT）的可行性，研究内容包括急性副作用和剂量体积直方图（DVH）数据。
本研究回顾性分析了 40 例中危局限性前列腺癌患者的临床资料，所有患者均在本单位采用每日图像引导 SIB-IMRT 方案进行根治性治疗。计划靶区包括前列腺和精囊底部，外放安全边界 3mm（头尾方向外放 5mm），总剂量 70Gy，分割 35 次。将前列腺及外放 3mm（头尾方向外放 5mm）的区域设为推量区，给予 76Gy（2.17Gy/次）的 SIB-IMRT。为避免直肠接受超过 76Gy 的处方剂量，前直肠壁的剂量限制为 76Gy。前瞻性采用改良 CTCAE（常见不良事件术语标准）评估急性毒性。
SIB-IMRT 可实现良好的直肠剂量限制，尽管前直肠壁可以接受全推量。所有患者的直肠中位剂量为 38Gy，V65（接受至少 65Gy 的体积）、V70（接受至少 70Gy 的体积）和 V75（接受至少 75Gy 的体积）的中位值分别为 13.5%、9%和 3%。未观察到 4 级毒性。20%的患者出现急性 3 级毒性，仅表现为夜尿增多。25%的患者出现急性 2 级肠道毒性，57.5%的患者出现急性 2 级泌尿系统毒性。急性毒性与 DVH 数据无相关性。
本单位采用每日图像引导作为小安全边界的前提条件，制定的 SIB-IMRT 方案可以实现前列腺的剂量升级，而不会增加急性毒性。
