Intensity-modulated radiation therapy (IMRT) reduces small bowel, rectum, and bladder doses in patients with cervical cancer receiving pelvic and para-aortic irradiation
Intensity-modulated radiation therapy (IMRT) reduces small bowel, rectum, and bladder doses in patients with cervical cancer receiving pelvic and para-aortic irradiation
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DOI：
10.1016/s0360-3016(01)01664-9
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发表时间：
2001-09-01
影响因子：
7
通讯作者：
Low, D
中科院分区：
文献类型：
--
作者：
Portelance, L;Chao, KSC;Low, D
目的：新兴使用联合疗法（化疗和放射疗法）治疗宫颈癌患者与显着的胃肠道和泌尿生殖系统毒性相关。调强放射治疗（IMRT）有可能向目标结构提供足够的剂量，同时不影响正常器官，还可以在不增加胃肠道/泌尿生殖系统并发症的情况下，对骨盆或主动脉旁区域明显增大的转移性淋巴结进行剂量递增。我们进行了剂量分析，以确定调强放射治疗 (IMRT) 是否能够满足宫颈癌治疗的这些目标。方法和材料：检索 10 名宫颈癌患者的计算机断层扫描研究，并将其用作规划的解剖学参考。完成目标和关键结构勾画后，成像和轮廓数据被传输到 IMRT 规划系统（Corvus、Nomos）和三维规划系统（Focus、CMS），在此基础上导出 IMRT 以及采用两视野和四视野技术的传统规划。治疗计划是在这两个系统上按照统一的处方进行的，45 Gy 分 25 次照射到子宫、子宫颈、盆腔和主动脉旁淋巴结。对所有 IMRT 计划进行标准化，以获得具有 95% 等剂量曲线的子宫颈完全覆盖。获得所有计划的剂量体积直方图。进行Student's t检验以计算统计显着性。结果：接受IMRT技术规定剂量（45Gy）的小肠体积如下：四个视野，11.01+/-5.67%；七个字段，15.05 +/- 6.76%；和九个字段，13.56 +/- 5.30%。这些均明显优于两视野 (35.58 ± 13.84%) 和四视野 (34.24 +/- 17.82%) 传统技术 (p < 0.05)。接受大于处方剂量的剂量的直肠体积分数如下：四个视野，8.55+/-4.64%；七个字段，6.37 +/- 5.19%；九个字段，3.34 +/- 3.0%；相比之下，两视野传统技术为 84.01 +/- 18.37%，四视野传统技术为 46.37 +/- 24.97% (p < 0.001)。接受规定剂量及更高剂量的膀胱体积分数如下：四个视野，30.29+/-4.64%；七个字段，31.66 +/- 8.26%；和九个字段，26.91 +/- 5.57%。两视野 (92.89 +/- 35.26%) 和四视野 (60.48 +/- 31.80%) 技术的效果明显更差 (p < 0.05)。结论：在这项剂量学研究中，我们证明，在相似的靶区覆盖范围下，IMRT 治疗宫颈癌时，正常组织的保留优于 IMRT。 (C) 2001 爱思唯尔科学公司。
Purpose: The emergent use of combined modality approach (chemotherapy and radiation therapy) for the treatment of patients with cervical cancer is associated with significant gastrointestinal and genitourinary toxicity. Intensity-modulated radiation therapy (IMRT) has the potential to deliver adequate dose to the target structures while sparing the normal organs and could also allow for dose escalation to grossly enlarged metastatic lymph node in pelvic or para-aortic area without increasing gastrointestinal/genitourinary complications. We conducted a dosimetric analysis to determine if IMRT can meet these objectives in the treatment of cervical cancer.Methods and Materials: Computed tomography scan studies of 10 patients with cervical cancer were retrieved and used as anatomic references for planning. Upon the completion of target and critical structure delineation, the imaging and contour data were transferred to both an IMRT planning system (Corvus, Nomos) and a three-dimensional planning system (Focus, CMS) on which IMRT as well as conventional planning with two- and four-field techniques were derived. Treatment planning was done on these two systems with uniform prescription, 45 Gy in 25 fractions to the uterus, the cervix, and the pelvic and para-aortic lymph nodes. Normalization was done to all IMRT plans to obtain a full coverage of the cervix with the 95% isodose curve. Dose-volume histograms were obtained for all the plans. A Student's t test was performed to compute the statistical significance.Results: The volume of small bowel receiving the prescribed dose (45 Gy) with IMRT technique was as follows: four fields, 11.01 +/- 5.67%; seven fields, 15.05 +/- 6.76%; and nine fields, 13.56 +/- 5.30%. These were all significantly better than with two-field (35.58 13.84%) and four-field (34.24 +/- 17.82%) conventional techniques (p < 0.05). The fraction of rectal volume receiving a dose greater than the prescribed dose was as follows: four fields, 8.55 +/- 4.64%; seven fields, 6.37 +/- 5.19%; nine fields, 3.34 +/- 3.0%; in contrast to 84.01 +/- 18.37% with two-field and 46.37 +/- 24.97% with four-field conventional technique (p < 0.001). The fractional volume of bladder receiving the prescribed dose and higher was as follows: four fields, 30.29 +/- 4.64%; seven fields, 31.66 +/- 8.26%; and nine fields, 26.91 +/- 5.57%. It was significantly worse with the two-field (92.89 +/- 35.26%) and with the four-field (60.48 +/- 31.80%) techniques (p < 0.05).Conclusion: In this dosimetric study, we demonstrated that with similar target coverage, normal tissue sparing is superior with IMRT in the treatment of cervical cancer. (C) 2001 Elsevier Science Inc.