Sood Sumit, Ju Andrew W, Wang Honkung, Lei Siyuan, Uhm Sunghae, Zhang Guowei, Suy Simeng, Carroll John, Lynch John, Dritschilo Anatoly, Collins Sean P
Radiat Oncol. 2013 Aug 9;8:197. doi: 10.1186/1748-717X-8-197.
Treating prostate cancer with SBRT could potentially minimize radiation proctitis by reducing high-dose rectal irradiation. In addition, it offers the potential radiobiologic benefits of hypofractionation. This study reports the endoscopic changes and the associated clinical rectal toxicity in these patients.
We reviewed the records of patients treated from 2008-2011 for localized prostate cancer who had rectal endoscopy following SBRT. SBRT was delivered either as primary treatment in 5 fractions of 7-7.25 Gy, or as an initial boost in 3 fractions of 6.5 Gy followed by conventionally fractionated radiotherapy to 45-50.4 Gy. Endoscopic changes were graded using the Vienna Rectoscopy Score (VRS). Rectal toxicity was graded via CTCAEv.4. Rectal quality of life (QOL) was assessed via the bowel domain of the EPIC-26 questionnaire.
Fifty-one patients with a median 23 months follow-up were analyzed. Thirty-five patients completed SBRT monotherapy and 16 patients received SBRT as a boost to conventionally fractionated IMRT. The median interval from SBRT to rectal endoscopy was 13 months. Endoscopy revealed VRS Grade 1-2 telangiectasias for 10 patients and VRS Grade 1-2 mucosal edema for 12 patients. No rectal ulcerations, strictures or necrosis were observed. Grade 1-2 late rectal bleeding occurred in 10 patients. There were no CTCAEv.4 Grade ≥3 toxicities. Mean EPIC bowel scores decreased from a baseline value of 96.9 to 82.3 at 1-month, but subsequently increased to 91.0 at 24 months.
In this cohort that is skewed towards patients with rectal complaints, the rate and severity of endoscopic changes following SBRT is low. Rectal toxicity and QOL were comparable to patients treated with other radiation modalities. Prospective trials examining the endoscopic outcomes following SBRT for prostate cancer are needed for confirmation of the findings of this study.
The Georgetown Institutional Review Board has approved this retrospective study (IRB 2009-510).
采用立体定向体部放疗（SBRT）治疗前列腺癌，可通过减少直肠高剂量照射，将放射性直肠炎的发生风险降至最低。此外，它还具有超分割放疗的潜在放射生物学优势。本研究报告了这些患者的内镜检查变化及相关的临床直肠毒性。
我们回顾了2008年至2011年接受治疗的局限性前列腺癌患者的记录，这些患者在接受SBRT后接受了直肠内镜检查。SBRT作为主要治疗方式时，采用5次分割，每次7 - 7.25 Gy；或作为初始强化治疗，采用3次分割，每次6.5 Gy，随后进行常规分割放疗至45 - 50.4 Gy。内镜检查变化采用维也纳直肠镜评分（VRS）进行分级。直肠毒性通过美国国立综合癌症网络（NCCN）肿瘤学临床实践指南（第4版）（CTCAEv.4）进行分级。直肠生活质量（QOL）通过EPIC - 26问卷的肠道领域进行评估。
对51例患者进行了分析，中位随访时间为23个月。35例患者完成了SBRT单一疗法，16例患者接受SBRT作为常规分割调强放疗（IMRT）的强化治疗。从SBRT到直肠内镜检查的中位间隔时间为13个月。内镜检查显示，10例患者出现VRS 1 - 2级毛细血管扩张，12例患者出现VRS 1 - 2级黏膜水肿。未观察到直肠溃疡、狭窄或坏死。10例患者出现1 - 2级晚期直肠出血。未出现CTCAEv.4≥3级毒性反应。EPIC肠道评分的平均值从基线值96.9降至1个月时的82.3，但随后在24个月时升至91.0。
在这个偏向有直肠症状患者的队列中，SBRT后内镜检查变化的发生率和严重程度较低。直肠毒性和生活质量与接受其他放疗方式的患者相当。需要进行前瞻性试验来证实本研究关于前列腺癌SBRT后内镜检查结果的发现。
乔治敦机构审查委员会已批准这项回顾性研究（IRB 2009 - 510）。
