SpaceOAR,聚乙二醇水凝胶,在前列腺癌放射治疗期间减少直肠辐射暴露。以前,我们小组报道了水凝胶插入的改良技术,在前列腺尖部实现更大的分离距离。本研究旨在探讨前列腺尖部分离距离和我们的修正技术的影响,在质子束治疗(PBT)期间减少辐射暴露。我们纳入了330例接受PBT的患者,其相对生物学有效性(RBE)为63Gray(Gy),并将它们分为0组(没有间隔,n=141),1(间隔器在前列腺尖部水平处的分离距离<7.5mm,n=81),和2(距离≥7.5mm,n=108)。接受30-60Gy(RBE)的直肠容积,估计并描述为直肠V30-60(ml),增量为10Gy。第2组的直肠V30-60(ml)明显低于第1组,第1组明显低于第0组。在倾向得分匹配后,多变量逻辑回归分析显示,减少辐射暴露的最重要因素是我们改进的水凝胶插入技术.因此,使用水凝胶垫片扩大前列腺-直肠距离不仅在前列腺-中到前列腺-基础水平,而且在前列腺-顶点水平可以减少前列腺癌PBT中的辐射暴露。
SpaceOAR, a polyethylene-glycol hydrogel, reduces rectal radiation exposure during radiation therapy for prostate cancer. Previously, our group reported the modified technique of hydrogel insertion, which achieves greater separated distance at prostate-apex. This study aimed to investigate the impact of separated distance at prostate-apex and our modifier technique, on radiation exposure reduction during proton beam therapy (PBT). We included 330 patients undergoing PBT with the relative biological effectiveness (RBE) of 63 Gray (Gy) for localized prostate cancer, and categorized them into groups 0 (no spacer, n = 141), 1 (separated distance of spacer at the prostate-apex level < 7.5 mm, n = 81), and 2 (distance ≥ 7.5 mm, n = 108). The rectal volumes to receive 30-60 Gy (RBE), was estimated and described as Rectal V30-60 (ml) in 10 Gy increments. The Rectal V30-60 (ml) was significantly lower in group 2 than in group 1, and in group 1 than in group 0. After propensity score matching, the multivariate logistic regression analysis revealed that the most significant factor to reduce radiation exposure was our modified technique of hydrogel insertion. Therefore, using a hydrogel spacer to expand the prostate-rectum distance not only at prostate-mid to prostate-base level but also at the prostate-apex level can reduce the radiation exposure in PBT for prostate cancer.