a Applied Radiation Therapy Trinity, Discipline of Radiation Therapy , Trinity College , Dublin , Ireland.
Acta Oncol. 2018 May;57(5):566-573. doi: 10.1080/0284186X.2017.1420908. Epub 2018 Jan 4.
Large variations in the shape and size of the bladder volume are commonly observed in bladder cancer radiotherapy (RT). The clinical target volume (CTV) is therefore frequently inadequately treated and large isotropic margins are inappropriate in terms of dose to organs at risk (OAR); thereby making adaptive radiotherapy (ART) attractive for this tumour site. There are various methods of ART delivery, however, for bladder cancer, plan libraries are frequently used.
A review of published studies on plan libraries for bladder cancer using four databases (Pubmed, Science Direct, Embase and Cochrane Library) was conducted. The endpoints selected were accuracy and feasibility of initiation of a plan library strategy into a RT department.
Twenty-four articles were included in this review. The majority of studies reported improvement in accuracy with 10 studies showing an improvement in planning target volume (PTV) and CTV coverage with plan libraries, some by up to 24%. Seventeen studies showed a dose reduction to OARs, particularly the small bowel V45Gy, V40Gy, V30Gy and V10Gy, and the rectal V30Gy. However, the occurrence of no suitable plan was reported in six studies, with three studies showing no significant difference between adaptive and non-adaptive strategies in terms of target coverage. In addition, inter-observer variability in plan selection appears to remain problematic. The additional resources, education and technology required for the initiation of plan library selection for bladder cancer may hinder its routine clinical implementation, with eight studies illustrating increased treatment time required.
While there is a growing body of evidence in support of plan libraries for bladder RT, many studies differed in their delivery approach. The advent of the clinical use of the MRI-linear accelerator will provide RT departments with the opportunity to consider daily online adaption for bladder cancer as an alternate to plan library approaches.
膀胱癌放射治疗（RT）中常观察到膀胱容积的形状和大小存在较大差异。因此，临床靶区（CTV）经常不能得到充分治疗，对于危及器官（OAR）而言，各向同性边界过大不合适；从而使自适应放疗（ART）对该肿瘤部位具有吸引力。ART 有多种实施方法，但对于膀胱癌，通常使用计划库。
对使用四个数据库（Pubmed、Science Direct、Embase 和 Cochrane Library）发表的膀胱癌计划库研究进行了综述。选择的终点是将计划库策略引入 RT 部门的准确性和可行性。
本综述共纳入 24 篇文章。大多数研究报告计划库的准确性有所提高，有 10 项研究表明计划库可提高 PTV 和 CTV 的覆盖范围，有些提高了 24%。17 项研究显示 OAR 剂量降低，特别是小肠 V45Gy、V40Gy、V30Gy 和 V10Gy，以及直肠 V30Gy。然而，有 6 项研究报告没有合适的计划，有 3 项研究表明在靶区覆盖方面，自适应策略与非自适应策略之间没有显著差异。此外，计划选择的观察者间变异性似乎仍然是一个问题。为膀胱癌启动计划库选择而需要的额外资源、教育和技术可能会阻碍其常规临床实施，有 8 项研究表明治疗所需时间增加。
尽管有越来越多的证据支持膀胱癌 RT 的计划库，但许多研究在其实施方法上存在差异。MRI-直线加速器的临床应用将为 RT 部门提供机会，考虑将每日在线自适应作为替代计划库方法用于膀胱癌。
