Zelefsky M J, Fuks Z, Happersett L, Lee H J, Ling C C, Burman C M, Hunt M, Wolfe T, Venkatraman E S, Jackson A, Skwarchuk M, Leibel S A
Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA.
Radiother Oncol. 2000 Jun;55(3):241-9. doi: 10.1016/s0167-8140(99)00100-0.
To compare acute and late toxicities of high-dose radiation for prostate cancer delivered by either conventional three-dimensional conformal radiation therapy (3D-CRT) or intensity modulated radiation therapy (IMRT).
Between September 1992 and February 1998, 61 patients with clinical stage T1c- T3 prostate cancer were treated with 3D-CRT and 171 with IMRT to a prescribed dose of 81 Gy. To quantitatively evaluate the differences between conventional 3D-CRT and IMRT, 20 randomly selected patients were planned concomitantly by both techniques and the resulting treatment plans were compared. Acute and late radiation-induced morbidity was evaluated in all patients and graded according to the Radiation Therapy Oncology Group toxicity scale.
Compared with conventional 3D-CRT, IMRT improved the coverage of the clinical target volume (CTV) by the prescription dose and reduced the volumes of the rectal and bladder walls carried to high dose levels (P<0.01), indicating improved conformality with IMRT. Acute and late urinary toxicities were not significantly different for the two methods. However, the combined rates of acute grade 1 and 2 rectal toxicities and the risk of late grade 2 rectal bleeding were significantly lower in the IMRT patients. The 2-year actuarial risk of grade 2 bleeding was 2% for IMRT and 10% for conventional 3D-CRT (P<0.001).
The data demonstrate the feasibility and safety of high-dose IMRT for patients with localized prostate cancer and provide a proof-of-principle that this method improves dose conformality relative to tumor coverage and exposure to normal tissues.
比较传统三维适形放射治疗（3D-CRT）与调强放射治疗（IMRT）对前列腺癌进行高剂量放射治疗时的急性和晚期毒性。
1992年9月至1998年2月期间，61例临床分期为T1c - T3期的前列腺癌患者接受了3D-CRT治疗，171例患者接受了IMRT治疗，处方剂量均为81 Gy。为了定量评估传统3D-CRT与IMRT之间的差异，随机选择20例患者同时采用两种技术进行治疗计划制定，并对所得治疗计划进行比较。对所有患者评估急性和晚期放射诱发的发病率，并根据放射肿瘤学组毒性量表进行分级。
与传统3D-CRT相比，IMRT提高了临床靶区（CTV）的处方剂量覆盖范围，并减少了直肠和膀胱壁接受高剂量水平照射的体积（P<0.01），表明IMRT的适形性更好。两种方法的急性和晚期泌尿毒性无显著差异。然而，IMRT患者急性1级和2级直肠毒性的合并发生率以及晚期2级直肠出血的风险显著更低。IMRT患者2级出血的2年精算风险为2%，传统3D-CRT为10%（P<0.001）。
数据表明高剂量IMRT对局限性前列腺癌患者具有可行性和安全性，并提供了一个原理证明，即该方法相对于肿瘤覆盖和正常组织暴露而言，改善了剂量适形性。
