Hyperfractionated intensity‐modulated proton therapy for pharyngeal cancer with variable relative biological effectiveness: A simulation study
Hyperfractionated intensity‐modulated proton therapy for pharyngeal cancer with variable relative biological effectiveness: A simulation study
复制标题
具有可变相对生物有效性的超分割调强质子治疗咽癌：一项模拟研究
DOI：
10.1002/mp.16064
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发表时间：
2022
期刊：
影响因子：
3.8
通讯作者：
Aoyama Hidefumi
中科院分区：
文献类型：
--
作者：
Kasamatsu Koki;Matsuura Taeko;Yasuda Koichi;Miyazaki Koichi;Takao Seishin;Tamura Masaya;Otsuka Manami;Uchinami Yusuke;Aoyama Hidefumi
背景质子的相对生物学效应（RBE）被认为与生物学参数和剂量分数有关。虽然超分割光子治疗是有效的治疗头颈部肿瘤的患者，其影响下的可变RBE的强度调制质子治疗（IMPT）还没有详细investigated.PurposeTo研究的影响可变RBE的超分割IMPT治疗咽癌。我们研究了生物有效剂量（BED），以确定理论上有效的超分割治疗方案。方法采用3例咽癌患者的治疗计划，定义临床靶体积（CTV）和软组织（急性和迟发反应）的ΔBED为可变RBE的改变方案与恒定RBE的常规方案的BED之差。综合计算了几种参数组合（治疗天数、分次次数和处方剂量）的ΔBED。在候选时间表中，通常给出CTV的较高ΔBED的时间表被选择作为结果时间表。BED体积直方图被用来比较变量RBE和fractionation.ResultsIn常规的时间表的影响，与恒定的RBE相比，变量RBE导致在一个平均2.6和2.7戈伊的BEDmeanfor CTV和软组织（急性反应）的三个计划，分别减少。此外，软组织（晚期反应）的BED平均值增加了7.4戈伊，表明RBE增加的潜在风险。综合计算ΔBED，超分割方案为80.52戈伊（RBE = 1.1）/66次，6.5周。当使用可变RBE时，与常规方案相比，超分割方案使CTV的平均BED增加了7.6戈伊;然而，这与软组织（急性反应）的7.8戈伊增加有关。软组织（晚期反应）的BED平均值下降了2.4戈伊.ConclusionThe结果表明，可变RBE对IMPT咽癌的潜在影响，但超分割的可能性可能超过这种影响。尽管生物学上的不确定性要求保守使用所得到的时间表，但超分割预计是咽癌IMPT的有效策略。
BackgroundThe relative biological effectiveness (RBE) of proton is considered to be dependent on biological parameters and fractional dose. While hyperfractionated photon therapy was effective in the treatment of patients with head and neck cancers, its effect in intensity‐modulated proton therapy (IMPT) under the variable RBE has not been investigated in detail.PurposeTo study the effect of variable RBE on hyperfractionated IMPT for the treatment of pharyngeal cancer. We investigated the biologically effective dose (BED) to determine the theoretical effective hyperfractionated schedule.MethodsThe treatment plans of three pharyngeal cancer patients were used to define the ΔBED for the clinical target volume (CTV) and soft tissue (acute and late reaction) as the difference between the BED for the altered schedule with variable RBE and conventional schedule with constant RBE. The ΔBED with several combinations of parameters (treatment days, number of fractions, and prescribed dose) was comprehensively calculated. Of the candidate schedules, the one that commonly gave a higher ΔBED for CTV was selected as the resultant schedule. The BED volume histogram was used to compare the influence of variable RBE and fractionation.ResultsIn the conventional schedule, compared with the constant RBE, the variable RBE resulted in a mean 2.6 and 2.7 Gy reduction of BEDmeanfor the CTV and soft tissue (acute reaction) of the three plans, respectively. Moreover, the BEDmeanfor soft tissue (late reaction) increased by 7.4 Gy, indicating a potential risk of increased RBE. Comprehensive calculation of the ΔBED resulted in the hyperfractionated schedule of 80.52 Gy (RBE = 1.1)/66 fractions in 6.5 weeks. When variable RBE was used, compared with the conventional schedule, the hyperfractionated schedule increased the BEDmeanfor CTV by 7.6 Gy; however, this was associated with a 7.8 Gy increase for soft tissue (acute reaction). The BEDmeanfor soft tissue (late reaction) decreased by 2.4 Gy.ConclusionThe results indicated a potential effect of the variable RBE on IMPT for pharyngeal cancer but with the possibility that hyperfractionation could outweigh this effect. Although biological uncertainties require conservative use of the resultant schedule, hyperfractionation is expected to be an effective strategy in IMPT for pharyngeal cancer.