[Comparison with dose-volume histograms of two conformal irradiation techniques used for the treatment of T2N0M0 nasopharyngeal cancer, one with association of photons and protons and another with photons alone].
[Comparison with dose-volume histograms of two conformal irradiation techniques used for the treatment of T2N0M0 nasopharyngeal cancer, one with association of photons and protons and another with photons alone].
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DOI：
10.1016/s1278-3218(02)00222-6
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发表时间：
2002-12-01
期刊：
影响因子：
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通讯作者：
Mazeron, J J
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作者：
Noel, G;Boisserie, G;Mazeron, J J
目的-鼻咽癌的局部控制率与肿瘤体积内的总剂量之间存在关系。相反，剂量和照射体积与并发症风险之间的关系尚未明确定义。这就是为什么，在局部晚期鼻咽癌患者中，我们比较了从两种3D适形照射技术获得的照射组织的剂量体积分布。患者和方法-2000年1月至2001年6月，5例患者，3名男性和2名女性，中位年龄为32岁，并提出了T4N0M0鼻咽癌接受放化疗。放射治疗结合光子和质子束和铂为基础的化疗在三个静脉注射在第1，22，43天的照射。为了计算剂量，对所有患者进行CT扫描和MRI。根据图像勾画大体肿瘤体积（GTV），定义三个临床肿瘤体积，CTV1为GTV和整个鼻咽，CTV2为CTV加上10 mm边缘，CTV3为CTV2和淋巴结区域（颈部和锁骨下）。淋巴结区预防剂量为44戈伊。CTV2和GTV或CTV1内的处方剂量分别为54戈伊/CGE（钴戈伊当量，EBR = 1，1）和70戈伊/CGE。照射剂量为1.8或2.0戈伊/CGE，光子剂量为44戈伊或54戈伊，质子剂量为16或26 CGE。根据质子和光子剂量学计划和单独光子理论剂量学获得的剂量-体积直方图，针对不同的感兴趣体积、GTV、CTV2和危险器官，（视神经，视交叉，内耳，脑干，颞叶），我们比较了最大值的平均值，最小和平均剂量以及不同等剂量所包含的感兴趣器官体积的平均值。结果-计算的最小，在GTV内输送的最大和平均剂量对于组合光子和质子的治疗优于单独光子的治疗。70戈伊/CGE等剂量所包含的平均GTV与单独的光子相比大65%。构象比（95%等剂量所包含的组织体积/95%等剂量所包含的GTV）为3.1，与之相比，单独使用光子时为5.7。对于CTV2，根据两种照射技术，不同标准无差异。对于关键的放射敏感器官，大多数标准的比较都有利于质子和光子的结合。总体而言，78%的标准是赞成的association.Conclusion-对于局部晚期鼻咽癌没有临床淋巴结肿大，照射光子和质子增加了肿瘤体积照射在规定的剂量和减少的体积或关键器官照射和总剂量内交付。
Purpose- There is a relationship between the local control rate of the nasopharyngeal cancer and the total dose delivered within the tumoral volume. In contrast, the relation between the dose and the irradiated volume and the risk of complication is not clearly defined. That is why, in patients presenting with a locally advanced nasopharyngeal cancer, we compared the dose-volume distribution of irradiated tissues, obtained from two 3D conformal irradiation techniques. Patients and methods- Between January 2000 and June 2001, 5 patients, 3 males and 2 females, with a median age of 32 years and presenting with a T4N0M0 nasopharyngeal cancer received a chemoradiotherapy. Radiotherapy combined photons and protons beams and the platin-based chemotherapy was delivered in three intravenous injections at d1, 22, 43 of the irradiation. To calculate the dosimetry, a CT scan and a MRI were performed in all the patients. The gross tumor volume (GTV) was delineated from the imagery, three clinical tumor volumes were defined, the CTV1 was the GTV and the whole nasopharynx, the CTV2 was the CTV plus a 10 mm-margin and the CTV3 was the CTV2 and the nodes areas (cervical and subclavicular). Prophylactic dose within node areas was 44 Gy. Prescribed doses within CTV2 and GTV or CTV1 were 54 Gy/CGE (Cobalt Gy Equivalent, for an EBR = 1,1) and 70 Gy/CGE, respectively. Irradiation was delivered with fractions of 1.8 or 2.0 Gy/CGE, with 44 Gy or 54 Gy by photons and with 16 or 26 CGE by protons. According to dose-volume histograms obtained from the dosimetry planning by protons and photons and from the theoretical dosimetry by photons lonely, for the different volumes of interest, GTV, CTV2, and organs at risk (optic nerves, chiasm, internal ears, brainstem, temporal lobes), we compared the averages of the maximum, minimum and mean doses and the averages of the volumes of organs of interest encompassed by different isodoses.Results- Calculated averages of minimum, maximum and mean doses delivered within GTV were superior for the treatment with combined photons and protons than with photons alone. The average GTV encompassed by the 70 Gy/CGE isodose was larger by 65% with the association compared to photons alone. The conformation ratio (tissue volume encompassed by the 95% isodose/GTV encompassed by the 95% isodose) was 3.1 with the association compared to 5.7 with photons alone. For the CTV2, there were no differences in different criteria according to the both irradiation techniques. For the critical, radiosensitive organs, the comparison of the majority of the criteria was in favour of the association of protons and photons. Overall, 78% of the criteria were in favour of the association.Conclusion- For locally advanced nasopharyngeal cancer without clinical adenopathy, irradiation by photons and protons increases the tumor volume irradiated at the prescribed dose and decreases the volume or critical organs irradiated and the total dose delivered within them.