Department of Radiation Oncology, CNRS UMR 6543, Cancer Center Antoine-Lacassagne, University Nice Sophia Antipolis, 33 Avenue Valombrose, 06189 Nice, France.
Nat Rev Urol. 2011 Nov 8;9(1):23-9. doi: 10.1038/nrurol.2011.173.
Organ preservation protocols that incorporate chemoradiotherapy have shown good efficacy in bladder cancer. Owing to changes in rectal filling, urinary inflow and subsequent bladder volume with bladder wall deformations, irradiation must take into account interfractional and intrafractional internal target motion. Growing evidence suggests that image guidance during irradiation is essential in order to appropriately treat bladder cancer in this way. We performed a literature search on the imaging techniques and margins used for radiation therapy planning in the context of whole-bladder and partial-bladder irradiation. The most common image-guided radiation therapy (IGRT) method was based on cone-beam CT using anisotropic margins. The role of cine-MRI for the prediction of intraindividual bladder changes, in association with cone-beam CT or ultrasonography, is promising. Drinking protocols, diet and laxatives were used in most cases to minimize large variations in bladder size and shape. IGRT is crucial for avoiding tumor undercoverage and undue toxicity during radiation therapy for bladder cancer. IGRT-based adaptive radiation therapy can be performed using cone-beam CT or ultrasonography: modeling of bladder changes with cine-MRI or other imaging techniques might also be useful for facilitating adaptive radiation therapy with personalized margins.
包含放化疗的器官保存方案在膀胱癌中显示出良好的疗效。由于直肠充盈、尿流和随后的膀胱体积随膀胱壁变形而改变，放疗必须考虑分次内和分次内的内部靶区运动。越来越多的证据表明，为了以这种方式适当治疗膀胱癌，在放疗过程中进行图像引导是必不可少的。我们对全膀胱和部分膀胱照射中用于放疗计划的成像技术和边缘进行了文献检索。最常见的图像引导放疗 (IGRT) 方法是基于使用各向异性边缘的锥形束 CT。电影 MRI 与锥形束 CT 或超声联合预测个体内膀胱变化的作用具有很大的前景。在大多数情况下，采用饮协议、饮食和泻药来尽量减少膀胱大小和形状的大幅变化。IGRT 对于避免膀胱癌放疗中肿瘤覆盖不足和毒性过大至关重要。可以使用锥形束 CT 或超声进行基于 IGRT 的自适应放疗：使用电影 MRI 或其他成像技术对膀胱变化进行建模，也可能有助于通过个性化边缘进行自适应放疗。
