Intensity-modulated radiotherapy in nasopharyngeal carcinoma: Dosimetric advantage over conventional plans and feasibility of dose escalation
Intensity-modulated radiotherapy in nasopharyngeal carcinoma: Dosimetric advantage over conventional plans and feasibility of dose escalation
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DOI：
10.1016/s0360-3016(03)00075-0
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发表时间：
2003-05-01
影响因子：
7
通讯作者：
Teo, PML
中科院分区：
文献类型：
--
作者：
Kam, MKM;Chau, RMC;Teo, PML
目的：比较调强放疗（IMRT）与二维放疗（2D-RT）和三维适形放疗（3D-CRT）在鼻咽癌不同阶段的治疗计划，探讨局部晚期鼻咽癌剂量递增的可行性。三个不同阶段的病人选择T1 N 0 M0、T2 bN 2 M0伴茎突后延长和T4 N2 M0三种不同的治疗方法，对每一个患者制定了IMRT治疗计划（66戈伊），并比较了靶区覆盖率、正常组织保留率和肿瘤控制概率/正常组织并发症概率值。在T2 b期和T4期患者中，IMRT 66-戈伊计划与使用3 mm微型多叶准直器的3D-CRT 14-戈伊boost计划相结合，并将总和计划的剂量体积直方图与其相应的66-戈伊2D-RT计划进行比较。在2D-RT、3D-CRT和IMRT治疗计划的剂量学比较中，T1 N 0 M0患者IMRT对腮腺和颞下颌关节的保留较好（剂量为50%腮腺体积，分别为57戈伊、50戈伊和31戈伊）。在T2 bN 2 M0患者中，计划靶体积的95%体积的剂量从2D-RT的57.5戈伊提高到3D-CRT的64.8戈伊和IMRT的68戈伊。在T4 N2 M0患者中，IMRT计划在靶区覆盖和脑干/颞叶保留方面均有所改善。在局部晚期疾病的剂量递增研究中，IMRT 66戈伊加14戈伊3D-CRT boost通过向靶区提供更高的剂量而使正常器官低于最大耐受剂量，从而实现了治疗比的提高。结论：IMRT由于其剂量学优势，可用于治疗所有阶段的非转移性鼻咽癌。在疾病早期，它提供了更好的腮腺保护。在局部晚期疾病中，IMRT提供了更好的肿瘤覆盖和正常器官保留，并允许剂量递增的空间。(C)2003年爱思唯尔公司
Purpose: To compare intensity-modulated radiotherapy (IMRT) with two-dimensional RT (2D-RT) and three-dimensional conformal radiotherapy (3D-CRT) treatment plans in different stages of nasopharyngeal carcinoma and to explore the feasibility of dose escalation in locally advanced disease.Methods and Materials: Three patients with different stages (T1N0M0, T2bN2M0 with retrostyloid extension, and T4N2M0) were selected, and 2D-RT, 3D-CRT, and IMRT treatment plans (66 Gy) were made for each of them and compared with respect to target coverage, normal tissue sparing, and tumor control probability/normal tissue complication probability values. In the Stage T2b and T4 patients, the IMRT 66-Gy plan was combined with a 3D-CRT 14-Gy boost plan using a 3-mm micromultileaf collimator, and the dose-volume histograms of the summed plans were compared with their corresponding 66-Gy 2D-RT plans.Results: In the dosimetric comparison of 2D-RT, 3D-CRT, and IMRT treatment plans, the T1N0M0 patient had better sparing of the parotid glands and temporomandibular joints with IMRT (dose to 50% parotid volume, 57 Gy, 50 Gy, and 31 Gy, respectively). In the T2bN2M0 patient, the dose to 95% volume of the planning target volume improved from 57.5 Gy in 2D-RT to 64.8 Gy in 3D-CRT and 68 Gy in IMRT. In the T4N2M0 patient, improvement in both target coverage and brainstem/temporal lobe sparing was seen with IMRT planning. In the dose-escalation study for locally advanced disease, IMRT 66 Gy plus 14 Gy 3D-CRT boost achieved an improvement in the therapeutic ratio by delivering a higher dose to the target while keeping the normal organs below the maximal tolerance dose.Conclusion: IMRT is useful in treating all stages of nonmetastatic nasopharyngeal carcinoma because of its dosimetric advantages. In early-stage disease, it provides better parotid gland sparing. In locally advanced disease, IMRT offers better tumor coverage and normal organ sparing and allows room for dose escalation. (C) 2003 Elsevier Inc.