Predictors of Rectal Tolerance Observed in a Dose-Escalated Phase 1-2 Trial of Stereotactic Body Radiation Therapy for Prostate Cancer
Predictors of Rectal Tolerance Observed in a Dose-Escalated Phase 1-2 Trial of Stereotactic Body Radiation Therapy for Prostate Cancer
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DOI：
10.1016/j.ijrobp.2014.03.012
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发表时间：
2014-07-01
影响因子：
7
通讯作者：
Timmerman, Robert D.
中科院分区：
文献类型：
--
作者：
Kim, D. W. Nathan;Cho, L. Chinsoo;Timmerman, Robert D.
目的：传达在局部前列腺癌的5分割立体定向体部放射治疗（SBRT）中测试的最高剂量水平下严重直肠毒性的孤立病例的发生;并合理地测试潜在的因果机制以指导未来的研究和实验，以帮助减轻或完全避免这种严重的肠损伤。分析了2006年至2011年入组的91例剂量递增患者的临床和治疗计划数据（45、47.5和50戈伊分5次）SBRT治疗局限性前列腺癌的1/2期临床研究。在最高剂量水平下，6.6%的治疗患者（91例中的6例）发生了高度直肠毒性，其中5例需要结肠造口术。3+级迟发性直肠毒性与接受50戈伊照射的直肠壁体积>3 cm（3）（P <0.05）和接受39戈伊照射的直肠壁周长的35%（P= 0.003）密切相关。2+级急性直肠毒性与>50%直肠壁周长至24戈伊的治疗显著相关（P=.010）。结论：在考虑高剂量SBRT治疗包括前列腺癌在内的肠结构附近肿瘤时，应谨慎。根据生理学原则定义了阈值剂量限制，如果遵守，可以最大限度地降低严重直肠毒性的风险。(C)2014 Elsevier Inc.
Purpose: To convey the occurrence of isolated cases of severe rectal toxicity at the highest dose level tested in 5-fraction stereotactic body radiation therapy (SBRT) for localized prostate cancer; and to rationally test potential causal mechanisms to guide future studies and experiments to aid in mitigating or altogether avoiding such severe bowel injury.Methods and Materials: Clinical and treatment planning data were analyzed from 91 patients enrolled from 2006 to 2011 on a dose-escalation (45, 47.5, and 50 Gy in 5 fractions) phase 1/2 clinical study of SBRT for localized prostate cancer.Results: At the highest dose level, 6.6% of patients treated (6 of 91) developed high-grade rectal toxicity, 5 of whom required colostomy. Grade 3+ delayed rectal toxicity was strongly correlated with volume of rectal wall receiving 50 Gy >3 cm(3) (P35% circumference of rectal wall to 39 Gy (P=.003). Grade 2+ acute rectal toxicity was significantly correlated with treatment of >50% circumference of rectal wall to 24 Gy (P=.010).Conclusion: Caution is advised when considering high-dose SBRT for treatment of tumors near bowel structures, including prostate cancer. Threshold dose constraints developed from physiologic principles are defined, and if respected can minimize risk of severe rectal toxicity. (C) 2014 Elsevier Inc.