Mangar S A, Foo K, Norman A, Khoo V, Shahidi M, Dearnaley D P, Horwich A, Huddart R A
Academic Radiotherapy, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK.
Clin Oncol (R Coll Radiol). 2006 Aug;18(6):466-73. doi: 10.1016/j.clon.2006.04.008.
The radiation dose used to treat bladder cancer is limited by the risk of inducing severe late bladder toxicity. Retrospective data suggest that radiation tolerance is greater for partial rather than whole bladder irradiation. Limiting the high-dose region to a section of the bladder may reduce toxicity, opening the way for dose escalation. The aims of this study were to establish the efficacy and compare the late toxicity between (1) a two-phase technique limiting the high-dose area and (2) a conventional single-phase radiotherapy to the whole bladder.
A cohort study was undertaken of 229 patients with invasive bladder cancer treated with computed tomography-planned radical radiotherapy at the Royal Marsden Hospital from 1984 to 1998. In total, 154 patients received a single-phase treatment to the whole bladder with a 2 cm margin. Seventy-five patients with solitary, well-localised tumours were selected for treatment using a two-phase technique. The first phase (12 Gy) aimed to treat the tumour with a 2 cm margin. A second phase treated the whole bladder with 52 Gy. One hundred and forty-one patients were planned to receive a dose of 60-64 Gy/30-32 fractions over 6-6.5 weeks, whereas 88 patients received an accelerated regime. Data on late bladder and bowel toxicity (using Radiation Therapy Oncology Group criteria) were collected prospectively at the annual review.
At the 5-year follow-up there was no difference in overall survival (hazard ratio = 0.91, 95% confidence interval 0.64-1.3) or failure-free survival (hazard ratio = 1.02, 95% confidence interval 0.73-1.43) between the two techniques. The two-phase reduced volume treatment was less toxic, with a 19% absolute reduction in overall grade 3-4 late toxicity (P = 0.02). These differences were more marked for bladder toxicity compared with bowel toxicity.
The two-phase reduced volume technique was associated with less bladder and bowel toxicity than conventional whole bladder radiotherapy without evidence of impaired survival.
用于治疗膀胱癌的放射剂量受到诱发严重晚期膀胱毒性风险的限制。回顾性数据表明，部分膀胱照射的放射耐受性高于全膀胱照射。将高剂量区域限制在膀胱的一部分可能会降低毒性，为剂量增加开辟道路。本研究的目的是确定（1）限制高剂量区域的两阶段技术与（2）全膀胱常规单阶段放射治疗之间的疗效并比较晚期毒性。
对1984年至1998年在皇家马斯登医院接受计算机断层扫描计划的根治性放射治疗的229例浸润性膀胱癌患者进行了队列研究。共有154例患者接受了全膀胱单阶段治疗，边缘为2厘米。75例孤立、定位良好的肿瘤患者被选择采用两阶段技术进行治疗。第一阶段（12 Gy）旨在治疗边缘为2厘米的肿瘤。第二阶段用52 Gy治疗全膀胱。141例患者计划在6 - 6.5周内接受60 - 64 Gy/30 - 32分次的剂量，而88例患者接受了加速方案。在年度复查时前瞻性收集晚期膀胱和肠道毒性数据（使用放射治疗肿瘤学组标准）。
在5年随访时，两种技术在总生存率（风险比 = 0.91，95%置信区间0.64 - 1.3）或无失败生存率（风险比 = 1.02，95%置信区间0.73 - 1.43）方面没有差异。两阶段减少体积治疗毒性较小，3 - 4级晚期总体毒性绝对降低19%（P = 0.02）。与肠道毒性相比，这些差异在膀胱毒性方面更为明显。
与传统的全膀胱放射治疗相比，两阶段减少体积技术导致的膀胱和肠道毒性较小，且没有生存受损的证据。
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