Department of Radiation and Clinical Oncology, Multiscan Pardubice, Pardubice, Czech Republic.
Int J Radiat Oncol Biol Phys. 2013 Jul 15;86(4):769-76. doi: 10.1016/j.ijrobp.2013.03.018. Epub 2013 Apr 26.
The study aimed to analyze the dose-volume profiles of 3-dimensional radiation therapy (3D-CRT) and intensity modulated RT (IMRT) in the treatment of prostate carcinoma and to specify the profiles responsible for the development of gastrointestinal (GI) toxicity.
In the period 1997 to 2007, 483 patients with prostate carcinoma in stage T1-3 N0 (pN0) M0 were treated with definitive RT. Two groups of patients were defined for the analysis: the 3D-CRT group (n=305 patients) and the IMRT group (n=178 patients). In the entire cohort of 483 patients, the median follow-up time reached 4.4 years (range, 2.0-11.7 years). The cumulative absolute and relative volumes of irradiated rectum exposed to a given dose (area under the dose-volume curve, AUC) were estimated. The receiver operating characteristic analysis was then used to search for the optimal dose and volume cutoff points with the potential to distinguish patients with enhanced or escalated toxicity.
Despite the application of high doses (78-82 Gy) in the IMRT group, GI toxicity was lower in that group than in the group treated by 3D-CRT with prescribed doses of 70 to 74 Gy. Both RT methods showed specific rectal dose-volume distribution curves. The total AUC values for IMRT were significantly lower than those for 3D-CRT. Furthermore, IMRT significantly decreased the rectal volume receiving low to intermediate radiation doses in comparison with 3D-CRT; specific cutoff limits predictable for the level of GI toxicity are presented and defined in our work.
Total area under the dose-volume profiles and specific cutoff points in low and intermediate dose levels have significant predictive potential toward the RT GI toxicity. In treatment planning, it seems that it is valuable to take into consideration the entire dose-volume primary distribution.
本研究旨在分析三维适形放疗（3D-CRT）和调强放疗（IMRT）治疗前列腺癌的剂量-体积曲线，并确定导致胃肠道（GI）毒性的剂量-体积曲线特征。
1997 年至 2007 年期间，对 483 例 T1-3N0（pN0）M0 期前列腺癌患者进行了根治性放疗。为分析将患者分为 3D-CRT 组（n=305 例）和 IMRT 组（n=178 例）。在整个 483 例患者队列中，中位随访时间达到 4.4 年（范围，2.0-11.7 年）。估计了接受特定剂量照射的直肠的累积绝对和相对体积（剂量-体积曲线下面积，AUC）。然后，使用接收者操作特征分析寻找具有潜在区分增强或升级毒性的最佳剂量和体积截止点。
尽管 IMRT 组应用了高剂量（78-82 Gy），但 GI 毒性仍低于 3D-CRT 组（70-74 Gy 处方剂量）。两种放疗方法均显示出特定的直肠剂量-体积分布曲线。IMRT 的总 AUC 值明显低于 3D-CRT。此外，与 3D-CRT 相比，IMRT 显著降低了直肠接受低至中等辐射剂量的体积；本文提出并定义了可预测 GI 毒性水平的特定截止限制。
剂量-体积曲线的总 AUC 值和低、中剂量水平的特定截止点对放疗 GI 毒性具有显著的预测潜力。在治疗计划中，考虑整个剂量-体积初始分布似乎是有价值的。
