Abstract：
OBJECTIVE: Between 10 and 40% of patients with cancer will develop one or more brain metastases (BMs). Stereotactic radiotherapy (SRT) is part of the therapeutic arsenal for the treatment of de novo or recurrent BM. Its main interest is to delay whole brain radiation therapy (WBRT), which may cause cognitive toxicity. However, SRT is not exempt from long-term toxicity, and the most widely known SRT is radionecrosis (RN). The objective of this study was to analyze the occurrence of RN per BM and per patient.
METHODS: Between 2010 and 2020, data from 184 patients treated for 915 BMs by two to six SRT sessions for local or distant brain recurrence without previous or intercurrent WBRT were retrospectively reviewed. RN was examined on trimestral follow-up MRI and potentially confirmed by surgery or nuclear medicine. For each BM and SRT session plan, summation V12Gy, V14Gy, V21Gy and V23Gy isodoses were collected. Volumes of intersections were created between the 12Gy isodose at the first SRT and the 18Gy isodose of the following SRT (V18-12Gy).
RESULTS: At the end of follow-up, 23.0% of patients presented RN, and 6.3% of BM presented RN. Median follow-up of BM was 13.3 months (95%CI 18.3-20.8). The median interval between BM irradiation and RN was 8.7 months (95% CI 9.2-14.7). Six-, 12- and 24-month RN-free survival rates per BM were 75%, 54% and 29%, respectively. The median RN-free survival per patient was 15.3 months (95% CI 13.6-18.1). In multivariate analysis, the occurrence of RN per BM was statistically associated with local reirradiation (P<0.001) and the number of SRTs (P<0.001). In univariate analysis, the occurrence of RN per patient was statistically associated with the sum of all V18-12Gy (P=0.02). No statistical association was found in multivariate analysis. A sum of all V18-12Gy of less than 1.5ml was associated with a 14.6% risk of RN, compared with 35.6% when the sum of all V18-12Gy was superior to 1.5ml. The sum of all V18-12Gy larger than 1.5ml was associated with a 74% specificity and 53% sensitivity of RN (P<0.001).
CONCLUSIONS: Based on these results, a small number of BMs show RN during repeated SRT for local or distant recurrent BMs. Local reirradiation was the most predictive factor of brain RN. A V18-12Gy larger than 7.6ml in the case of local reirradiation or larger than 1.5ml in proximity reirradiation were prognostic factors of RN. The more BM patients need radiation therapy, and the longer they survive after irradiation, the higher their individual risk of developing RN.
METHODS: Between 2010 and 2020, data from 184 patients treated for 915 BMs by two to six SRT sessions for local or distant brain recurrence without previous or intercurrent WBRT were retrospectively reviewed. RN was examined on trimestral follow-up MRI and potentially confirmed by surgery or nuclear medicine. For each BM and SRT session plan, summation V12Gy, V14Gy, V21Gy and V23Gy isodoses were collected. Volumes of intersections were created between the 12Gy isodose at the first SRT and the 18Gy isodose of the following SRT (V18-12Gy).
RESULTS: At the end of follow-up, 23.0% of patients presented RN, and 6.3% of BM presented RN. Median follow-up of BM was 13.3 months (95%CI 18.3-20.8). The median interval between BM irradiation and RN was 8.7 months (95% CI 9.2-14.7). Six-, 12- and 24-month RN-free survival rates per BM were 75%, 54% and 29%, respectively. The median RN-free survival per patient was 15.3 months (95% CI 13.6-18.1). In multivariate analysis, the occurrence of RN per BM was statistically associated with local reirradiation (P<0.001) and the number of SRTs (P<0.001). In univariate analysis, the occurrence of RN per patient was statistically associated with the sum of all V18-12Gy (P=0.02). No statistical association was found in multivariate analysis. A sum of all V18-12Gy of less than 1.5ml was associated with a 14.6% risk of RN, compared with 35.6% when the sum of all V18-12Gy was superior to 1.5ml. The sum of all V18-12Gy larger than 1.5ml was associated with a 74% specificity and 53% sensitivity of RN (P<0.001).
CONCLUSIONS: Based on these results, a small number of BMs show RN during repeated SRT for local or distant recurrent BMs. Local reirradiation was the most predictive factor of brain RN. A V18-12Gy larger than 7.6ml in the case of local reirradiation or larger than 1.5ml in proximity reirradiation were prognostic factors of RN. The more BM patients need radiation therapy, and the longer they survive after irradiation, the higher their individual risk of developing RN.
摘要：
目的：10％至40％的癌症患者会发生一种或多种脑转移（BMs）。立体定向放射治疗（SRT）是用于治疗从头或复发性BM的治疗武器库的一部分。它的主要兴趣是延迟全脑放射治疗（WBRT），这可能会导致认知毒性。然而,SRT不能免除长期毒性，最广为人知的SRT是放射性坏死（RN）。这项研究的目的是分析每个BM和每个患者的RN发生率。
方法：在2010年至2020年之间，回顾性分析了184例接受915例BMs治疗的患者的数据，这些患者通过2至6次SRT治疗局部或远处脑复发，而没有先前或并发的WBRT。对RN进行了随访MRI检查，并可能通过手术或核医学证实。对于每个BM和SRT会话计划，求和V12Gy，V14Gy,收集V21Gy和V23Gy等剂量。在第一个SRT的12Gy等剂量和随后的SRT的18Gy等剂量(V18-12Gy)之间产生交叉点的体积。
结果：在随访结束时，23.0%的患者出现RN，6.3%的BM呈现RN。BM的中位随访时间为13.3个月（95CI18.3-20.8）。BM照射和RN之间的中位间隔为8.7个月（95％CI9.2-14.7）。Six-,每个BM的12个月和24个月无RN生存率为75％，54%和29%，分别。每位患者的中位无RN生存期为15.3个月(95%CI13.6-18.1)。在多变量分析中，每个BM的RN发生率与局部再照射(P<0.001)和SRT的数量(P<0.001)有统计学关联.在单变量分析中，每名患者的RN发生率与所有V18-12Gy的总和具有统计学相关性(P=0.02).在多变量分析中没有发现统计学关联。所有V18-12Gy的总和小于1.5ml与RN的14.6％风险相关，当所有V18-12Gy的总和优于1.5ml时，为35.6%。所有大于1.5ml的V18-12Gy的总和与RN的74%特异性和53%敏感性相关(P<0.001)。
结论：基于这些结果，在局部或远处复发的重复SRT中，少量BMS显示RN。局部再照射是脑RN的最预测因素。在局部再照射的情况下V18-12Gy大于7.6ml或在邻近再照射中大于1.5ml是RN的预后因素。需要放射治疗的BM患者越多，它们在照射后存活的时间越长，他们个体发展RN的风险越高。
方法：在2010年至2020年之间，回顾性分析了184例接受915例BMs治疗的患者的数据，这些患者通过2至6次SRT治疗局部或远处脑复发，而没有先前或并发的WBRT。对RN进行了随访MRI检查，并可能通过手术或核医学证实。对于每个BM和SRT会话计划，求和V12Gy，V14Gy,收集V21Gy和V23Gy等剂量。在第一个SRT的12Gy等剂量和随后的SRT的18Gy等剂量(V18-12Gy)之间产生交叉点的体积。
结果：在随访结束时，23.0%的患者出现RN，6.3%的BM呈现RN。BM的中位随访时间为13.3个月（95CI18.3-20.8）。BM照射和RN之间的中位间隔为8.7个月（95％CI9.2-14.7）。Six-,每个BM的12个月和24个月无RN生存率为75％，54%和29%，分别。每位患者的中位无RN生存期为15.3个月(95%CI13.6-18.1)。在多变量分析中，每个BM的RN发生率与局部再照射(P<0.001)和SRT的数量(P<0.001)有统计学关联.在单变量分析中，每名患者的RN发生率与所有V18-12Gy的总和具有统计学相关性(P=0.02).在多变量分析中没有发现统计学关联。所有V18-12Gy的总和小于1.5ml与RN的14.6％风险相关，当所有V18-12Gy的总和优于1.5ml时，为35.6%。所有大于1.5ml的V18-12Gy的总和与RN的74%特异性和53%敏感性相关(P<0.001)。
结论：基于这些结果，在局部或远处复发的重复SRT中，少量BMS显示RN。局部再照射是脑RN的最预测因素。在局部再照射的情况下V18-12Gy大于7.6ml或在邻近再照射中大于1.5ml是RN的预后因素。需要放射治疗的BM患者越多，它们在照射后存活的时间越长，他们个体发展RN的风险越高。
