Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana, Turkey.
Acta Oncol. 2011 Nov;50(8):1167-74. doi: 10.3109/0284186X.2011.584557. Epub 2011 Aug 24.
Radiotherapy (RT) for abdominal and pelvic malignancies often causes severe small bowel toxicity. Citrulline concentrations are known to decrease with intestinal failure. We thus evaluated the feasibility of plasma citrulline levels in predicting radiation-induced intestinal toxicity.
Fifty-three patients (36 prostate cancer, 17 endometrial cancer) who received 45 Gy pelvic RT using conventional fractionation were prospectively evaluated. Patients with prostate cancer received an additional 25-30.6 Gy conformal boost. Plasma citrulline levels were assessed on day 0, mid- (week 3) and post-RT (week 8), and four months post-RT. Dose-volume histogram, citrulline concentration changes, and weekly intestinal toxicity scores were analyzed.
Mean age was 63 years (range: 43-81 years) and mean baseline citrulline concentration was 38.0 ± 10.1 μmol/l. Citrulline concentrations were significantly reduced at week 3 (27.4 ± 5.9 μmol/l; p < 0.0001), treatment end (29.9 ± 8.8 μmol/l; p < 0.0001), and four months post-treatment (34.3 ± 12.1; p = 0.01). The following factor pairs were significantly positively correlated: Citrulline concentration/mean bowel dose during, end of treatment, and four months post-RT; dose-volume parameters/citrulline change groups; cumulative mean radiation dose/intestinal toxicity at end and four months post-RT; citrulline changes/intestinal toxicity during and end of RT. Citrulline concentration changes significantly differed during treatment according to RTOG intestinal toxicity grades (p < 0.0001). Although the citrulline changes differed significantly within RTOG intestinal toxicity grades (p = 0.003), the difference between Grade 0 and Grade 1 did not differ significantly at the end of the treatment. At four months after RT, no significant differences were apparent.
Citrulline-based assessment scores are objective and should be considered in measuring radiation-induced intestinal toxicity.
腹部和盆腔恶性肿瘤的放射治疗（RT）常导致严重的小肠毒性。已知肠衰竭时瓜氨酸浓度降低。因此，我们评估了血浆瓜氨酸水平预测放射性肠毒性的可行性。
前瞻性评估了 53 例接受常规分割 45 Gy 盆腔 RT 的患者（36 例前列腺癌，17 例子宫内膜癌）。前列腺癌患者接受了 25-30.6 Gy 的适形加量。在第 0 天、治疗中期（第 3 周）和治疗后（第 8 周）以及治疗后 4 个月评估血浆瓜氨酸水平。分析剂量-体积直方图、瓜氨酸浓度变化和每周肠道毒性评分。
平均年龄为 63 岁（范围：43-81 岁），基线瓜氨酸浓度为 38.0±10.1μmol/l。第 3 周（27.4±5.9μmol/l；p＜0.0001）、治疗结束时（29.9±8.8μmol/l；p＜0.0001）和治疗后 4 个月（34.3±12.1；p=0.01）时瓜氨酸浓度明显降低。以下因素对呈显著正相关：治疗期间、治疗结束时和治疗后 4 个月的瓜氨酸浓度/平均肠剂量；剂量-体积参数/瓜氨酸变化组；累积平均辐射剂量/治疗结束和治疗后 4 个月的肠道毒性；治疗期间和治疗结束时的瓜氨酸变化/肠道毒性。根据 RTOG 肠道毒性分级，治疗期间瓜氨酸浓度变化差异显著（p＜0.0001）。尽管 RTOG 肠道毒性分级内的瓜氨酸变化差异显著（p=0.003），但治疗结束时 0 级和 1 级之间的差异无统计学意义。在 RT 后 4 个月，无明显差异。
基于瓜氨酸的评估评分是客观的，应考虑用于测量放射性肠毒性。
