Although past studies have associated external-beam radiation therapy (EBRT) with higher incidences of secondary neoplasms (SNs), its effect on SN development from pediatric low-grade gliomas (LGGs), defined as WHO grade I and II gliomas of astrocytic or oligodendrocytic origin, is not well understood. Utilizing a national cancer registry, the authors sought to characterize the risk of SN development after EBRT treatment of pediatric LGG.

A total of 1245 pediatric patient (aged 0–17 years) records from 1973 to 2015 were assembled from the Surveillance, Epidemiology, and End Results (SEER) database. Univariable and multivariable subdistribution hazard regression models were used to evaluate the prognostic impact of demographic, tumor, and treatment-related covariates. Propensity score matching was used to balance baseline characteristics. Cumulative incidence analyses measured the time to, and rate of, SN development, stratified by receipt of EBRT and controlled for competing mortality risk. The Fine and Gray semiparametric model was used to estimate future SN risk in EBRT- and non–EBRT-treated pediatric patients.

In this study, 366 patients received EBRT and 879 did not. Forty-six patients developed SNs after an LGG diagnosis, and 27 of these patients received EBRT (OR 3.61, 95% CI 1.90–6.95; p < 0.001). For patients alive 30 years from the initial LGG diagnosis, the absolute risk of SN development in the EBRT-treated cohort was 12.61% (95% CI 8.31–13.00) compared with 4.99% (95% CI 4.38–12.23) in the non–EBRT-treated cohort (p = 0.013). Cumulative incidence curves that were adjusted for competing events still demonstrated higher rates of SN development in the EBRT-treated patients with LGGs. After matching across available covariates and again adjusting for the competing risk of mortality, a clear association between EBRT and SN development remained (subhazard ratio 2.26, 95% CI 1.21–4.20; p = 0.010).

Radiation therapy was associated with an increased risk of future SNs for pediatric patients surviving LGGs. These data suggest that the long-term implications of EBRT should be considered when making treatment decisions for this patient population

尽管过去的研究已经将外束放射治疗 (EBRT) 与继发性肿瘤 (SN) 的高发病率联系起来，但它对小儿低级别胶质瘤 (LGG) 的 SN 发展的影响，定义为星形细胞或少突胶质细胞的 WHO I 级和 II 级胶质瘤起源，不是很清楚。利用国家癌症登记处，作者试图描述小儿 LGG EBRT 治疗后 SN 发展的风险。

从监测、流行病学和最终结果 (SEER) 数据库收集了 1973 年至 2015 年的 1245 名儿科患者（0-17 岁）记录。使用单变量和多变量子分布风险回归模型来评估人口统计学、肿瘤和治疗相关协变量的预后影响。倾向得分匹配用于平衡基线特征。累积发生率分析测量了 SN 发展的时间和速度，通过接受 EBRT 进行分层并控制竞争性死亡风险。Fine 和 Gray 半参数模型用于估计 EBRT 和非 EBRT 治疗的儿科患者的未来 SN 风险。

在这项研究中，366 名患者接受了 EBRT，879 名未接受。46 名患者在诊断为 LGG 后出现 SN，其中 27 名患者接受了 EBRT（OR 3.61，95% CI 1.90–6.95；p < 0.001）。对于从初始 LGG 诊断开始存活 30 年的患者，接受 EBRT 治疗的队列中发生 SN 的绝对风险为 12.61%（95% CI 8.31-13.00），而非治疗组为 4.99%（95% CI 4.38-12.23）接受 EBRT 治疗的队列（p = 0.013）。针对竞争事件进行调整的累积发生率曲线仍然表明，在接受 EBRT 治疗的 LGG 患者中，SN 发生率较高。在匹配可用的协变量并再次调整死亡的竞争风险后，EBRT 和 SN 发展之间仍然存在明显的关联（亚风险比 2.26，95% CI 1.21–4.20；p = 0.010）。

放射治疗与 LGG 幸存的儿科患者未来 SN 的风险增加有关。这些数据表明，在为该患者群体制定治疗决策时应考虑 EBRT 的长期影响