Yeo Inhwan, Goughenour Alexander, Cernica George, Nie Wei, Joo Mindy, Wang Peng, Fan Jiajin, Parniani Ashkan, Kanani Samir
Department of Advanced Radiation and Proton Therapy, INOVA Schar Cancer Institute, Fairfax, VA, USA.
Int J Part Ther. 2024 Nov 1;14:100635. doi: 10.1016/j.ijpt.2024.100635. eCollection 2024 Dec.
To compare intensity-modulated proton therapy with CyberKnife (CK) therapy for hypo-fractionated treatments of prostate with focal boost, as a first planning study for prostate with dose escalation to a dominant intraprostatic lesion (DIL).
Ten patients who possess one DIL in their prostate and their CK plans that were used to treat the planning target volume of prostate were chosen. Six of the plans were further escalated to DIL. Intensity-modulated proton therapy plans were created for the patients with robust optimization, accounting for setup and range uncertainties for the clinical target volume (CTV) of prostate. The CK plans were then compared with the proton plans.
In the worst scenario of the robust evaluation, the proton plans reasonably met all objectives and constraints used in CK planning for both CTV coverage and organs-at-risk (OAR) sparing. Under the nominal scenario of the robust optimization, the proton plans produced dosimetric values comparable to those by the CK plans for both CTV and DIL coverage. The average dose to CTV, outside DIL and urethra, was found lower in the proton plans than in the CK plans due to the uncertainties. A similar trend was observed for the dose conformity to CTV. These two findings, however, were not planning objectives. Regarding organs-at-risk sparing, the proton plans in the nominal scenario were comparable to the CK plans for doses >18.125 Gy; for doses below it, the proton performed better. This study offers a basis for a clinical trial of treatment of prostate cancer by proton that may be transferred from the CK system in our center.
The dosimetric objectives and constraints used in the CK plans were achieved with the proton plans.
作为对前列腺中主要前列腺内病变（DIL）进行剂量递增的前列腺分割治疗的首次规划研究，比较调强质子治疗与射波刀（CK）治疗用于前列腺局部加量的低分割治疗效果。
选择10例前列腺中有一个DIL且其CK计划用于治疗前列腺计划靶区的患者。其中6个计划进一步递增至DIL。为患者创建了调强质子治疗计划，并进行了稳健优化，考虑了前列腺临床靶区（CTV）的摆位和射程不确定性。然后将CK计划与质子计划进行比较。
在稳健评估的最差情况下，质子计划在CTV覆盖和危及器官（OAR）保护方面合理地满足了CK计划中使用的所有目标和约束。在稳健优化的标称情况下，质子计划在CTV和DIL覆盖方面产生的剂量学值与CK计划相当。由于不确定性，发现质子计划中CTV、DIL外和尿道外的平均剂量低于CK计划。在CTV剂量适形性方面也观察到类似趋势。然而，这两个发现并非规划目标。关于危及器官保护，标称情况下质子计划对于剂量>18.125 Gy与CK计划相当；对于低于该剂量的情况，质子计划表现更好。本研究为在我们中心可能从CK系统转换的质子治疗前列腺癌的临床试验提供了基础。
质子计划实现了CK计划中使用的剂量学目标和约束。
